WO2016009450A2

WO2016009450A2 - Photonic devices by organo-metallic halides based perovskites material and its method of preparation

Info

Publication number: WO2016009450A2
Application number: PCT/IN2015/000288
Authority: WO
Inventors: Dinesh Kabra; Kumar Naresh Kumawat; Amrita Dey
Original assignee: Indian Institute of Technology Bombay
Current assignee: Indian Institute of Technology Bombay
Priority date: 2014-07-17
Filing date: 2015-07-16
Publication date: 2016-01-21
Anticipated expiration: 2017-01-17
Also published as: WO2016009450A3

Abstract

Disclosed is a photonic device for electroluminescence application and its method of preparation wherein device comprises a perovskite semiconductor film layer disposed between a n-type region and a p-type region, wherein the perovskite semiconductor film layer is made of an organo-metallic halide (ABX3) and is tuned to a band gap, wherein the band gap varies from NIR to visible range at room temperature and at least two inter layers, the at least two inter layers incorporated between the p-type region and perovskite semiconductor film layer and the n-type region and perovksite semiconductor film layer.

Description

PHOTONIC DEVICES BY ORGANO-METALLIC HALIDES BASED PEROVSKITES MATERIAL AND ITS METHOD OF PREPARATION

TECHNICAL FIELD

The present invention relates to photonic devices in the field of optoelectronics, more specifically photonic devices for electroluminescence application that are based on perovskite semiconductors. The invention also relates to the process of making photonic devices, which are based on perovskite semiconductors.

BACKGROUND

The field of optoelectronics has seen breakneck developments and improvements in the recent past although the research has been largely confined to solar cells and its optimization owning to the need of low carbon emission. Other photonic devices especially electroluminescence devices currently available have numerous issues and need to be addressed.

In a particular Chinese patent CN103700768, "One kind of perovskite structure solar cell and preparation method" which illustrates a solar cell and a particular kind of perovskite structure accommodated in it along with its preparation method. Here, the perovskite structure and preparation method is specific to a solar cell.

Therefore, there is a need for expansive research and venturing in to other photonic and electroluminescence devices with high efficiencies.

OBJECT OF THE INVENTION

1. It is an objective of the invention to provide a photonic device with electroluminescence as effect by virtue of organo-metallic halides based perovskites material. 2. It is another objective of the invention to provide a high performance, low cost and environment friendly electroluminescence device.

3. It is another objective to provide a method of preparation of perovskite film layer tunable to large range of wavelength of emission spectra from UV-Vis-NIR spectral range.

SUMMARY

The present invention describes a photonic device or more specifically an electroluminescence device, which comprises an organo-metallic halide based perovskite semiconductor layer and a method of preparation of the same.

In one aspect of the invention, a photonic or an electroluminescent device with perovskite layer as an active layer is described. The perovskite layer in the photonic device is a mixed halide represented by ABX3, wherein A = R-NH3 (R is an alkyl group or aromatic group), B is a divalent metal cation (Cu²⁺, Ni²⁺, Co²⁺, Fe²⁺, Mn²⁺, Pd²⁺, Cd²⁺, Ge²⁺, Sn²⁺, Pb²⁺, Eu²⁺) and X (CI, Br or I) is a single or hybrid halide. In another aspect of the invention, the active organo-metallic halide-based perovskite semiconductors with band gaps varying from NIR to visible at room temperature are achieved. The Band gap of a semiconductor is varied by either changing of halide ion or by using mixed halide ion compositions and therefore the halide ion composition has an essential role to play in these photonic devices in lieu of the perovskite semiconductor layer. A method of processing photonic devices with electroluminescence application, with incorporated perovskite material tunable to a range of band gap is also described in the invention. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of a photonic device representing the various layers including the organo-metallic halide based perovskite semiconductor layer as a light emitting/responsive layer. Figure 2a represents the X-Ray diffraction of an as deposited perovskite (ABI3- xClx) film using spin coating technique on glass substrate and Figure 2b represents X-Ray diffraction of perovskite film on glass substrate after annealing at 90°C for 45 minutes.

Figure 3 represents X-ray diffraction of ABbperovskite material on glass substrate after annealing at 100°C for 15 min.

Figure 4 represents X-ray diffraction of ABBr3perovskite material on glass substrate after annealing at 100°C for 10 min.

Figure 5 represents X-ray diffraction of ABChperovskite material on glass substrate after annealing at 100°C for 1 min. Figure 6 represents x-ray diffraction of AB(Bri-_xCl_x)3 perovskite series on glass substrate. Here ABCb mixed with ABB in different concentration XRD was measured.

Figure 7 represents x-ray diffraction of AB(Ii_-xBr_x)3 perovskite series on glass substrate. Here ABBn mixed with ABI3 in different concentration XRD was measured.

Figure 8 represents first order peak position vs CI composition of AB(Bn._xCl )3 . Here ABCb mixed with ABBr3 in different concentration and first order XRD peak shift towards higher angle with CI composition.

Figure 9 represents first order peak position vs Br composition of AB(Ii_-xBr_x)3 . The ABBr₃ is mixed with ABCb in different concentration and first order XRD peak shift towards higher angle with Br composition. Figure 10 represents FESEM image of (a) ABI₃ (b) ABBr₃ (c) ABC and (d) ABI3- xClx on glass/PEDOT:PSS substrate after annealing.

Figure 11 represents FESEM image of AB(Bn-_xCl_x) series at different concentrations of CI and respective halide composition in the image.

Figure 12 represents FESEM image of AB(Il-xBrx) series at different concentrations of Br and respective halide composition in the image. Figure 13 represents Absorbance spectra (absorbance vs energy) of ABI3 (□), ABBr3 (o) and ABCb (Δ) perovskites on glass substrate after annealing.

Figure 14 represents Photoluminescence (PL vs energy) of ABI3 (□), ABBr₃ (o) and ABCb (Δ) perovskites on glass substrate after annealing.

Figure 15 represents Absorbance spectra of AB(Bri_-xClx)3 series using different Br/CI ratio to tune the band gap from 2.2 eV (green) 3.1 eV.

Figure 16 represents the Photoluminescence of AB(Bn_-xClx)₃ series using different Br/CI ratio to tune the band gap from 2.2 eV (green) 3.1 eV (UV).

Figure 17 represents Band gap vs CI composition of AB(Bn_-xClx)3 series and fitted (Red solid line) using second order polynomial to determine bowing parameter. Inset shows PLQE vs CI composition.

Figure 18represents Lattice parameter vs CI composition of AB(Bri-_xCl_x) series and fitted (red solid line) with straight line.

Figure 19 represents Absorbance spectra of AB(Ii_-xBrx)3 series using different- Br/1 ratio to tune the band gap from 2.2 eV (green) 1.6 eV (NIR). Figure 20 represents Photoluminescence of AB(Ii_-xBr_x)3 series using different Br/I ratio to tune the band gap from 2.2 eV (green) 3.1 eV (UV).

Figure 21 represents Band gap vs Br composition of AB(Ii_-xBr_x)3 series and fitted (Red solid line) using second order polynomial to determine bowing parameter.

Figure 22 represents Lattice parameter vs Br composition of AB(Bn_-xCl_x) series and fitted (red solid line) with straight line. Figure 23 represents Electroluminescence (EL) spectra of perovskite materials using ITO/HIL/Perovskite/EIL/metal electrode.

Figure 24 represents J-V-L characteristics of blue emitting perovskite ITO/PEDOT:PSS/ABBrl .08C11.92/PCBM/Ag and inset image of working blue PeLED inside the figure.

Figure 25 represents Cd/A vs Voltage (solid circle) and EQE vs Voltage (open circle) of ITO/PEDOT:PSS/ABBrl .08C11.92/PCBM/Ag PeLED. Figure 26 represents J-V-L characteristics of blue emitting perovskite ITO/PEDOT:PSS/ABBrl .08C11.92/PCBM/Ag and inset image of working blue PeLED inside the figure.

Figure 27 represents Cd/A vs Voltage (solid circle) and EQE vs Voltage (open circle) of ITO/PEDOT:PSS/ABBrl .08Cll .92/PCBM/Ag PeLED.

Figure 28 represents J-V-L characteristics of blue emitting perovskite ITO PEDOT:PSS/ABBrl .08C11.92/Ag and inset image of working blue PeLED inside the figure. Figure 29 represents J-V-L characteristics of blue emitting perovskite ITO/PEDOT:PSS/ABBr 1.08C11.92/Ag PeLED.

Figure 30 represents J-V-L of ITO/PEDOT: PSS/TPD/ABBr₃/Ag and inset image of working blue PeLED inside the figure.

Figure 31 represents Cd/A vs Voltage (empty circle) and EQE vs Voltage (solid circle) of ITO/PEDOT: PSS/TPD/ABBr₃/Ag PeLED. Figure 32 represents J-V-L of ITO/PEDOT:PSS/ABBrl.87C11.17/Ag PeLED.

Figure 33 represents Cd/A vs Voltage (empty circle) and EQE vs Voltage (solid circle) of ITO/PEDOT:PSS/TPD/ABBrl .87C11.17/Ag PeLED. Figure 34represents J-V-L characteristics of ITO/PEDOT:PSS/ABIi .25Bri.₇₅/Ag red PeLED.

Figure 35 represents Cd/A vs Voltage (empty circle) and EQE vs Voltage (solid circle) of ITO/PEDOT:PSS/TPD/ABIi ₂₅Br, ₇₅/Ag PeLED.

Figure 36 represents J-V (solid circle) and Radiance vs voltage for ITO/PEDOT: PSS/ABI3-xClx PCBM/Ag diode.

Figure 37a and 37b shows photo luminance spectra of perovskites film with various interfaces of charge transporting layers with respect to wavelength and energy, respectively.

Figure 38 represents absorbance, photoluminescence and electroluminescence measurements on energy and wavelength scales. Inset in forth quadrant of figure shows blue shifted EL with respect to higher injection current. Figure 39 represents (a) J-V-L characteristics, (b) luminance (solid) and power efficiency (open) vs applied bias, (c) luminance efficiency versus bias voltage and (d) external quantum efficiency vs. bias voltage for perovskite LED with structure of ITO/Ti0₂/Al₂03/CH3NH₃PbClBr/P3HT/Au, wherein the device area is 4.5 mm². Light emission peak wavelength is 680 nm.

Figure 40 wherein the four graphs represents J-V-L characteristics, luminance (solid) and power efficiency (open), luminance efficiency vs. bias voltage and external quantum efficiency vs. bias voltage for perovskite LED with device structure of ITO/ZnO/Ba(OH)2/CH₃NH3PbClBr/P₃HT/Au, wherein the Device area is 4.5 mm½nd the Light emission peak wavelength is 680 nm.

Figure 41 wherein the four graphs represents (a) I-V-L characteristics, (b) luminance (solid) and power efficiency (open)vs bias voltage, (c) luminance efficiency vs. bias voltage and (d) external quantum efficiency vs. bias voltage for perovskite LED(ITO/Ti0₂/ Al₂0₃/CH3NH₃PbClBr/Mo0₃/Au). Device area is 4.5 mm². Light emission peak wavelength is 680 nm.

Figure 42 represents J-V-L characteristics of mixed perovskite of different diodes fabricated on same substrate with device structure of ITO/PEDOT:PSS/CH3NH₃PbIxCli.x/PCBM/Ag. Light emission peak wavelength is 780 nm.

Figure 43 represents external quantum efficiency (EQE) for mixed perovskite LED in ITO/PEODT: PSS/Perovskite (CHsNFhPblxCbxVPCBM/Ag structure for different diodes on same substrate. Light emission peak wavelength is 780 nm.

Figure 44 represents external quantum efficiency (EQE) versus current density for mixed perovskite LEDs in ITO/PEODT: PSS/Perovskite (CH3NH₃PbI_xCl_3x)/PCBM/Ag structure for different diodes on same substrate. Figure 45 represents an overview of the synthesis of halide based perovskite materials.

Figure 46 represents an overview of the device fabrication of halide based perovskite materials.

DETAILED DESCRIPTION

The present invention is a photonic device especially for electroluminescence (EL) application. This electroluminescence device, which has a light emitting layer comprises a p-type region having a p-type layer for hole injection (hole injection/extraction layer). An n-type region having an n-type layer for electron injection (electron injection/extraction layer), an organo-metallic halide based perovskite semiconductor layer as an active layer (light emission), an interlayer incorporated between the p-type region and the perovskite layer and the n-type region and perovskite layer and two electrode for electrical contact.

Figure 1 is a schematic arrangement of the various layers along with the light emitting perovskite film. By perovskite, it is to be understood that the perovskite crystalline nature in various permutations and combinations is referred. The p-type region and n-type region can be an organic conducting polymer or inorganic or organic material.

Ideally, the perovskite semiconducting material is accountable for the photo generation and charge transportation and thereby enabling the device to be an electroluminescence device. This halide based perovskite can be a p-type or n-type or intrinsic semiconductor layer which is sandwiched in between p-type and n-type hole and electron injection layer respectively or in between one electrode and one p or n-type carrier injection layer and vice versa. The two electrodes mentioned above for electrical contact is such that one is a metallic reflective electrode and the other is a transparent material electrode. In one aspect of the invention, when the device is a general photonic/light emitting diode, the perovskite material can been deposited on top of the hole injection/extraction layer followed by a high electron affinity layer for electron injection/extraction and a contact electrode (low work function metal). In another aspect of the invention, for inverted light emitting diode/photonic devices, perovskites can be deposited on top of an electron injection/extraction layer followed up by high work-function conducting layer for holes injection/extraction from top contact electrode (high work-function metal).

The perovskite layer is a crystal structure, represented by the formula ABX3, where in "A" and "B" are first and second cations respectively and "X" is an anion. Now, A is represented by R-NH3. Again, R in this case is an alkyl group or aromatic group or a monovalent metal ion and B is a divalent metal cation. Preferably B is selected from the group of Cu²⁺, Ni²⁺, Co²⁺, Fe²⁺, Mn²⁺, Pd ⁺, Cd²⁺, Ge²⁺, Sn ⁺, Pb²⁺, Eu²⁺, etc. X is a single halide or a hybrid halide selected from the group of I, CI, Br and F and combinations thereof. For example, the perovskite structure combination used can be CFhNFbPbfli-xBrxK CH₃NH3Pb(Bri_-xClx)3, CH3NH3PbI₃-x_-yClxBr_y, or similar combinations (Ct NHsPbb-xClx) of perovskites materials where x varies from 0 to 1.

The morphology and crystallinity of the perovskite layer depends on the halide ion and substrate wetting conditions, where crystallite size varies from ~ 100s nm to few micrometers. Therefore, in lieu of the mentioned parameters that have a huge influence on the optical properties and performance of light emitting diodes (LEDs) using these perovskites as the active layer and photonic devices in general, a new avenue of materials for photonic devices and LEDs specifically is made available in the present invention.

The invention further describes a method of producing a photonic device with an organo-metallic halide based perovskite semiconductor film layer; the active layer in the photonic device. The low temperature solution processability and the completely tunable optical direct band gap over a wide range makes it a potential candidate for tandem solar cells, wavelength tune able light emitting diodes and electrical injection laser. Now, the band gap of semiconductor is varied by either changing of halide ion or by using mixed halide ion compositions. Furthermore, good wetting of the contact by the perovskite layer is very important for obtaining leakage free devices.

By way of example, the steps involved in the method of processing or producing a photonic device with perovskite semiconductor material have been described below:

The first step involves the synthesis of the precursor followed by the preparation of the perovskite precursor solution. Figure 45 represents an overview of steps in the synthesis of the perovskite materials to make the perovskite solution for the photonic devices and LED application.

Synthesis of CH₃NH₃I:

CH3NH3I was synthesized by reacting 33% by weight of methylamine (CH3NH2) in absolute ethanol (sigma Aldrich) solution with 57 % by weight of hydroiodic acid (HI) in aqueous (sigma Aldrich) solution in an equal (1 : 1) molar ratio. After which methylamine was poured into a round flask, kept at 0°C. Hydroiodic acid was added drop wise and stirred for two hours. The ensuing step is the usage of rotary evaporator to get crystalline methylammonium iodide, i.e., CH3NH3I, (MAI). The resulting precipitate is a white coloured precipitate and thereby serves as a confirmation of the crystallization of MAI. This white coloured precipitate of CH3NH3I was rinsed three times with diethyl ether for 30 minutes and dried using rotary evaporator at temperature and pressure conditions of 55°C and 500 mbar.

Synthesis of CE NftjBr:

CH₃NH3Br was synthesized by reacting 33% by weight of methylamine (CH3NH2) in absolute ethanol (sigma Aldrich) solution with 47 % by weight of hydrobromic acid (HBr) in aqueous solution (Merck) at equal (1 : 1 ) molar ratio. Following which, methylamine was poured in round flask, kept at 0°C. Hydrobromic acid was added drop wise in methylamine solution, and stirred for two hours. After that, rotary evaporator was used to get crystalline (MABr) methylammoniumbromide (CE NFhBr) which is a light orange colored precipitate thereby confirming the crystallization of MABr. The precipitate is then rinsed three times with diethyl ether for 30 minutes and dried using rotary evaporator, at 55°C and 500 mbar.

Synthesis of CHaNHaCl:

CH3NH3CI was synthesized using methylamine (CH3NH2) 33 wt% in absolute ethanol (Sigma Aldrich) solution and hydrochloric acid (HC1) 37wt% in aqueous (Merck) solution in equal (1 : 1) molar ratio. Methylamine was kept at 0 °C and Hydrochloric acid was added drop wise to it and stirred for two hours. After that, rotary evaporator was used to get crystalline methylammoniumchloride (CH3NH3CI). White colored precipitate confirmed the crystallization of CH3NH3CI. Further, it was rinsed three times with diethyl ether for 30 min and dried using a rotary evaporator at 50°C followed by vacuum drying for over night.

ClfcNHsPbb-xCh or (ABb-xCIx) solution precursor:

ABh xClx perovskite precursor is prepared by reacting methylammonium iodide (CH3NH3I) precipitate with lead chloride (PbC from Sigma-Aldrich) and later dissolved in (DMF) anhydrous dimethylformamide (C3H7NO from Sigma Aldrich) in 3: 1 molar ratio. In this precursor, 40% by weight was perovskite material and 60% by weight was DMF. The solution was stirred over night at room temperature in a nitrogen atmosphere inside a glove box (MBRUAN-MB200B).

In the above process lead(II)chloride PbCl₂ can be replaced by any divalent metal halide e.g. lead(II)bromide (PbBr ) lead(II)iodide (Pbl₂), tin(II)chloride (SnCb), tin(II)bromide (PbBr₂), tin(II)iodide (Snl₂), lead(II)iodide (Pbl₂) and copper halide (here halides are CI, Br and I) for tuning the perovskite band gap from UV to near IR, further varying the concentration of the perovskite. Synthesis of mixed perovskite methylammonium lead iodide chloride bromide (CH3NH3Pbl3-x_-yClxBr_y) solution precursor:

CHsNtbPbb-x-yCl Bry solution can be prepared by reacting methylammonium iodide (CH3NH3I) precipitate with lead(II)chloride (PbCb from Sigma-Aldrich) and lead bromide (PbBr₂ from sigma Aldrich) and the resulting mixture is dissolved in (C3H7NO) dimethylformamide (DMF) (Merck) in 3: 1 : 1 molar ratio. In this precursor, 40 % by weight was the perovskite material and 60 % by weight was DMF. This solution was stirred over night at room temperature in nitrogen atmosphere inside the glove box (MBRUAN-MB200B).

Yet again, lead(II)halide (PbCb) and lead(II)bromide (PbBr₂) can be replaced by any divalent metal halide (here halide are CI, Br and I) e.g. tin(II)chloride (SnCb), tin(II) bromide (PbBr₂) tin(II)iodide (Snl₂), lead(II)iodide (Pbl₂) and copper halide (here halide are CI, Br and I) for tuning the perovskite band gap.

Synthesis of methylammonium bromide CH Nt PbBn:

CF NF PbBn solution is prepared by reacting methylammonium bromide (CFbNFbBr) precipitate with lead bromide (PbBr₂fromSigma-Aldrich), and dissolved in (DMF) dimethylformamide (C3H7NO from Merck) in 1 : 1 molar ratio. In this precursor, 40% by weight was perovskite material and 60 % by weight was DMF. The resulting solution was stirred over night at room temperature in nitrogen atmosphere inside the glove box (MBRUAN-MB200B).

Synthesis of methyl ammonium lead chloride (CHjNFbPbCb):

Methylammonium chloride (ABCb), precipitate and PbCb, dissolved in DMSO in 1 : 1 molar ratio (ABCb 40wt% in DMSO). . In this precursor, 40% by weight was perovskite material and 60 % by weight was DMF. The resulting solution was stirred over night at room temperature in nitrogen atmosphere inside the glove box (MBRUAN-MB200B).

Synthesis of methyl ammonium lead chloride (CH3NH3PD (Bn-xCh) 3 : ABBr3 solution was prepared using, Methylammonium Bromide precipitate and PbBr₂, are dissolved in DMSO (Dimethyl sulfoxide) in 1 : 1 molar ratio (ABBr₃ 10wt% perovskite in DMSO). Similarly for ABCI3, Methylammoniumchloride precipitate and PbCl₂, dissolved in DMSO in 1 : 1 molar ratio (ABCb 10wt% in DMSO). After that for AB(Bn_-xCl)3 solution, we mixed ABCb and ABBr3 in volumetric ratio (1 :9, 1 :4, 3:7,2:3, 1 : 1, 6:5, 7:3, 4:2, 9: 1) in vials. The solution was stirred overnight at room temperature in nitrogen atmosphere.

Synthesis of methyl ammonium lead chloride (CH3NH3Pb(Ii-xBrx)3 :

ABBr₃ solution was prepared using, Methylammonium Bromide precipitate and PbBr₂, are dissolved in DMF in 1 : 1 molar ratio (ABBn 10wt% perovskite in DMF). Similarly for ABI3, methylammoniumiodide precipitate and Pbl₂, dissolved in DMSO in 1 : 1 molar ratio (ABI3 10wt% in DMF). After that for AB(Bn_-xCl)₃ solution, we mixed ABBr3 and ABI3 in volumetric ratio (1 :9, 1 :4, 3:7,2:3, 1 : 1, 6:5, 7:3, 4:2, 9: 1) in vials. The solution was stirred overnight at room temperature in nitrogen atmosphere. The ensuing step after the synthesis of various perovskite precursor solutions as mentioned above is the cleaning of the substrate in the photonic devices. Again by way of example, the cleaning is done in the following way:

The 50 mm x 50 mm x 1.1 mm ITO coated glass substrates (Lintec sheet resistance 7ohm) have been patterned using an optical mask in a double-sided aligner (DSA). The optimum size in to which the substrates were cut by a diamond cutter is 12.5 mm xl2.5 mm. All the substrates were cleaned with soap water, distilled water (DI), 2-propenol (IPA) and acetone for lOminutes successively in an ultra sonicator. Following which, the cleaned substrates have been put for oxygen plasma ashing at 100 Wt for 10 minutes.

The fabrication of the Photonic device using the perovskite material, which is an essential step, is carried out after cleaning the substrate. The fabrication varies depending on whether it is a standard regular device or inverted device. By definition a standard regular device is one where in the schematic order of the device the metal electrode is followed by an n-type semiconductor and the p-type electrode is coupled with the transparent electrode. An inverted device is where a p-type electrode follows the metal electrode and the n-type is coupled with the transparent electrode. Figure 46 represents a systematic overview of the Photoic device fabrication steps involved in various perovskite light emitting diode, specifically the Blue, Red, Green and the NIR photonic device. The step-by-step process using ClbNHsPbb- Clji tunable to a NIR photonic device or a LED for instance in a standard regular device is as follows:

Hole injection/extraction layer for regular (standard) devices PEDOT:PSS (Sigma aldrich) was spin coated at 4000 rpm for 60 seconds and then annealed at 150°C for 30 min under constant nitrogen flow. After which, the samples were transferred in to a nitrogen filled glove box. Then CFbNHsPb -xClx layer was deposited on PEDOT: PSS by spin coating at 2000 rpm for 60 seconds using CHsNHsPbb-xClx precursor. The perovskite layer was annealed at 100°C for 90min to evaporate the solvent and make a dense film of the perovskite. The confirmation test of perovskite film in this case is the film color change from yellow to brown after annealing it. Electron injection layer/extraction layer (PCMB) was deposited on the perovskite film by spin coating at 2000 rpm for 30seconds and annealed at 50°C for 20minutes.The electrode deposition step involves depositing of 200 nm Ag (silver) using evaporation technique in l l O^ mbar vacuum at room temperature.

Figure 2a represents the X-Ray diffraction of an as deposited perovskite (ABb-xCL) film using spin coating technique on glass substrate and Figure 2b represents X- Ray diffraction of perovskite film on glass substrate after annealing at 90°C for 45 minutes.

Figure 3 represents X-ray diffraction of ABI3 perovskite material on glass substrate after annealing at 100°C for 15 min.

Figure 4 represents X-ray diffraction of ABBr3 perovskite material on glass substrate after annealing at 100°C for 10 min. Figure 5 represents X-ray diffraction of ABCb perovskite material on glass substrate after annealing at 100°C for 1 min.

Figure 6 represents x-ray diffraction of AB(Bri-_xCl_x)3 perovskite series on glass substrate. Here ABCI3 mixed with ABBr3 in different concentration.

Figure 7 represents x-ray diffraction of AB(Ii- Br_x)3 perovskite series on glass substrate. Here ABBr3 mixed with ABI3 in different concentration.

The other methods, which can be employed in the deposition of perovskite material, can be by chemical vapor deposition (CVD), thermal evaporation or dip coating method or PLD (Plus Laser Deposition) or drop casting method or LPE (Liquid Phase epitaxy).

In the above process, the hole injection/extraction layer can be p-type organic or inorganic semiconducting or conducting materials preferably. Also, the PEDOT:PSS (hole injection/extraction) layer can be replaced by Spiro- MeOTAD(2,2',7,7'-tetrakis(N,Ndipmethoxyphenylamine)9,9spirobifluorene), P3HT(poly(3hexylthiophene-2,5-diyl)),DEH(4-(diethylamino)- benzaldehydediphenylhydrazone), PCPDTBT (Poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta [2, l -b;3,4-b']dithiophene)-alt-4,7(2, l,3-benzothiadiazole), ,PCDTBT(Poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl- 2\l',3'-benzothiadiazole), PTAA (Polybis(4-phenyl)(2,4,6- trimethylphenyl)amine),Nickel tri oxide (N1O3), and Molybdenum tri oxide(Mo03). And the electron injection layer can be replaced by any n-type semiconducting or conducting material e.g. Zinc oxide (ZnO), PC₆oBM, PCeiBM,

The electrode can be replaced by a high electron affinity material e.g. Gold (Au). In addition, the incorporation of a layer in between the n-type and perovskite or p- type and perovskite material would prevent the electroluminescence (EL) and photoluminescence (PL) quenching.

The step-by-step fabrication of LEDs/Photonic device using ClfcNHjPbls-x-y CIxBry (NIR) perovskite material by way of example in an inverted structure is as follows:

An electron injection layer/Extraction layer of Ti0₂ (500μ1 titanium di- isopropoxidebis (acetylacetonate) solution in 5ml anhydrous ethanol) was deposited on the ITO substrate by spray coating (wherein oxygen is used as a carriergas) at 450°C and annealed at 500°C for 30min.

In the case of ZnO deposition, (400 mg zinc acetate di-hydrate in 5ml methanol) it was carried out by spray coating at 370°C and annealed at same temperature for 15 minutes. Barium hydroxide (7mg/ml in 2-methoxy ethanol) was deposited on ZnO as a quenching layer by spin coating at 3000rpm for 60 seconds in N₂ (nitrogen) filled glove box. The ensuing deposition is of AI2O3 (<50 nm particle size (DLS), 20 Wt % in isopropanol Sigma Aldrich) on T1O2 by spin coating at 4000rpm for 60sec and annealed at 400°C forl 5minutes. After which, the samples were transferred in nitrogen filled glove box, and CH3NH3Pbl3-x-yClxBr_y layer was deposited on T1O2 and ZnO by spin coating at 2000rpm for 45 sec using

precursor. The films were annealed at 90°C for 90min to evaporate the solvent and make a dense film of perovskite. The change in film colour from yellow to brown after annealing it was a confirmation of it becoming a perovskite film.

P3HT solution (15mg/ml in chlorobenzene) was prepared and deposited by spin coating at 1500rpm for 30sec and annealed at 50°C for 15 min.

The deposition of a hole injection layer involves a 5 nm M0O3 layer deposited by thermal evaporation in lxl0^~6mbar vacuum.

A 100 nm Au (gold) was deposited using evaporation technique in lxl0^"6mbar vacuum. In an inverted device structure electron injection/extraction layer Ti0₂ or ZnO can be replaced by any n-type semiconducting organic or inorganic material e.g.

Similarly, the Ba(OH)2 layer can be replaced by a layer which prevents the EL and PL quenching across the interface e.g. TFB, TPD, PEI or Beta Alanine.

The step-by-step fabrication of Photonic device using CH3NibPbBr3 (Green) perovskite material by way of example in an inverted structure is as follows: Hole injection/extraction layer for regular (standard) devices PEDOT:PSS (Sigma aldrich) was spin coated at 4000 rpm for 60 seconds and then annealed at 150°C for 30 min under constant nitrogen flow. After which, the samples were transferred in to a nitrogen filled glove box. Then CH₃NH₃PbBr3 layer was deposited on PEDOT: PSS by spin coating, as spin coating gives a good crystalline film. Spin coating is carried out at 2000 rpm for 30 seconds using CH₃NH₃PbBr3 precursor. The film layer was annealed at 100°C for 15 min to evaporate the solvent and make a dense film of perovskite. The confirmation test of perovskite film in this case is the film color become orange after annealing it. Without and with Electron injection layer/extraction layer (PCMB) was deposited on the perovskite film by spin coating at 2000 rpm for 30seconds and annealed at 50°C for 20 minutes. The electrode deposition step involves depositing of 200 nm Ag (silver) using evaporation technique in lxl 0^"6mbar vacuum at room temperature.

In the above process, the hole injection/extraction layer can be p-type organic or inorganic semiconducting or conducting materials preferably. Also, the PEDOT.PSS (hole injection/extraction) layer can be replaced by Spiro- MeOTAD(2,2',7,7'-tetrakis(N,N-dipmethoxyphenylamine)9,9spirobifluorene), P3HT(poly(3hexylthiophene-2,5-diyl)),DEH(4-(diethylamino)- benzaldehydediphenylhydrazone), PCPDTBT (Poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta [2, 1 -b;3,4-b']dithiophene)-alt-4,7(2, 1 ,3-benzothiadiazole), ,PCDTBT(Poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4^,,7'-di-2-thienyl-

2',l',3^,-benzothiadiazole), PTAA (Polybis(4-phenyl)(2,4,6- trimethylphenyl)amine), Nickel tri oxide (Ni0₃), and Molybdenum tri oxide(Mo0₃). And the electron injection layer can be replaced by any n-type semiconducting or conducting material e.g. Zinc oxide (ZnO), PCBM, PC₆iBM, The electrode can be replaced by a high electron affinity material e.g. Gold (Au). In addition, the incorporation of a layer in between the n-type and perovskite or p- type and perovskite material would prevent the electroluminescence (EL) and photoluminescence (PL) quenching.

The step-by,-step fabrication of LEDs/Photonic device using CHsNibPbili- xBi^*x)3 (Red LED) perovskite material by way of example in regular structure is as follows: Hole injection/extraction layer for regular (standard) devices PEDOT:PSS (Sigma aldrich) was spin coated at 4000 rpm for 60 seconds and then annealed at 150°C for 30 min under constant nitrogen flow. After which, the samples were transferred in to a nitrogen filled glove box. Then CthNK PbOi-xBrx);? layer was deposited on PEDOT: PSS by spin coating at 2000 rpm for 30 seconds using CH₃NH3Pb(Ii-xBr_x) precursor. The film layer was annealed at 100°C for 15 min to evaporate the solvent and make a dense film of perovskite. The confirmation test of perovskite film in this case is the film colour becomes light orange after annealing it. Without and with electron injection layer/extraction layer (PCMB) was deposited on the perovskite film by spin coating at 2000 rpm for 30seconds and annealed at 50°C for 20 minutes. The electrode deposition step involves depositing of 200 nm Ag (silver) using evaporation technique in lxlO^mbar vacuum at room temperature.

The other methods, which can be employed in the deposition of perovskite material, can be by chemical vapour deposition (CVD), thermal evaporation or dip coating method or PLD (Plus Laser Deposition) or drop casting method or LPE (Liquid Phase epitaxy).

In the above process, the hole injection/extraction layer can be p-type organic or inorganic semiconducting or conducting materials preferably. Also, the PEDOT:PSS (hole injection/extraction) layer can be replaced by Spiro- MeOTAD(2,2',7,7'-tetrakis(N,N-dipmethoxyphenylamine)9,9spirobifluorene), P3HT(poly(3hexylthiophene-2,5-diyl)),DEH(4-(diethylamino)- benzaldehydediphenylhydrazone), PCPDTBT (Poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta [2, 1 -b;3,4-b']dithiophene)-alt-4,7(2, 1 ,3-benzothiadiazole), ,PCDTBT(Poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl- 2',l',3'-benzothiadiazole), PTAA (Polybis(4-phenyl)(2,4,6- trimethylphenyl)amine), Nickel tri oxide (N1O3), and Molybdenum tri oxide(Mo03). And the electron injection layer can be replaced by any n-type semiconducting or conducting material e.g. Zinc oxide (ZnO), PCBM, PCeiBM,

The step-by-step fabrication of LEDs/Photonic device using CH3NH3Pb(Ii- xBrx)3 (Blue LED) perovskite material by way of example in regular structure is as follows:

Hole injection/extraction layer for regular (standard) devices PEDOT:PSS (Sigma aldrich) was spin coated at 4000 rpm for 60 seconds and then annealed at 150°C for 30 min under constant nitrogen flow. After which, the samples were transferred in to a nitrogen filled glove box. Then CH3NH3Pb(Bri-_xCl_x)3 layer was deposited on PEDOT: PSS by spin coating at 2000 rpm for 30 seconds using CH3NH₃Pb(Bri._x Clx)3 precursor. The film layer was annealed at 100°C for 15 min to evaporate the solvent and make a dense film of perovskite. The confirmation test of perovskite film in this case is the film colour becomes light orange after annealing it. Without and with electron injection layer/extraction layer (PCMB) was deposited on the perovskite film by spin coating at 2000 rpm for 30seconds and annealed at 50°C for 20 minutes. The electrode deposition step involves depositing of 200 nm Ag (silver) using evaporation technique in lxl 0^"½ibar vacuum at room temperature. The other methods, which can be employed in the deposition of perovskite material, can be by chemical vapour deposition (CVD), thermal evaporation or dip coating method or PLD (Plus Laser Deposition) or drop casting method or LPE (Liquid Phase epitaxy).

In the above process, the hole injection/extraction layer can be p-type organic or inorganic semiconducting or conducting materials preferably. Also, the PEDOT:PSS (hole injection/extraction) layer can be replaced by Spiro- MeOTAD(2,2',7,7'-tetrakis(N,N-dipmethoxyphenylamine)9,9spirobifluorene), P₃HT(poly(3hexylthiophene-2,5-diyl)),DEH(4-(diethylamino)- benzaldehydediphenylhydrazone), PCPDTBT (Poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta [2, 1 -b;3,4-b']dithiophene)-alt-4,7(2, 1 ,3-benzothiadiazole), ,PCDTBT(Poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4^,,7^*-di-2-thienyl- 2', l',3'-benzothiadiazole), PTAA (Polybis(4-phenyl)(2,4,6- trimethylphenyl)amine), Nickel tri oxide (NiC ), and Molybdenum tri oxide(Mo03). And the electron injection layer can be replaced by any n-type semiconducting or conducting material e.g. Zinc oxide (ZnO), PCBM, PCeiBM, PC71BM. The electrode can be replaced by a high electron affinity material e.g. Gold (Au). In addition, the incorporation of a layer in between the n-type and perovskite or p- type and perovskite material would prevent the electroluminescence (EL) and photoluminescence (PL) quenching. The results in terms of the J-V-L characteristics, EL & PL studies under the purview of the examples of the PeLEDS described above are denoted in the form of the figures described below:

Figure 9 represents first order peak position vs Br composition of AB(Ii-_xBr_x)3 . Here ABBr3 mixed with ABCb in different concentration and first order XRD peak shift towards higher angle with Br composition. Figure 10 represents FESEM image of (a) ABI₃ (b) ABBr₃ (c)ABCband (d) ABI_3- xClx on glass/PEDOT:PSS substrate after annealing.

Figure 1 1 represents FESEM image of AB(Bri-xCl_x) series at different concentration of CI and respective halide composition in image. FESEM image of (a) ABBr2.49C10.51 (b) ABBrl .86C11.14 (c) ABBrl .5C11.5 (d)

ABBrl .08C11.92 (e) ABBr0.87C12.13 (f) ABBr0.21C12.79 perovskite films on ITO/PEDOT:PSSsubstarte after annealing has been illustrated. It is observed that perovskites filmcoverage is good and with chlorine content domain size of AB(Bn. xCl_x)₃ perovskite changed.

Figure 12 represents FESEM image of AB(Ii_-xBr_x) series at different concentration of Br and respective halide composition in image. Figure 13 represents Absorbance spectra (absorbance vs energy) of ABI3 (□), ABBr₃ (o) and ABC1₃ (Δ) perovskites on glass substrate after annealing.

Figure 14 represents Photoluminescence (PL vs energy) of ABI₃ (□), ABBr₃ (o) and ABCI3 (Δ) perovskites on glass substrate after annealing.

Figure 15 represents UV-Vis Absorbance spectra of AB(Bri_-xClx)₃ series using differentBr/Cl ratio to tune the band gap from 2.2 eV (green) 3.1 eV and where x varies from 0 to 1. Figure 16 represents Photoluminescence of AB(Bri-_xCl_x)₃ series using differentBr/Cl ratio to tune the band gap from 2.2 eV (green) 3.1 eV (UV). This photoluminescence spectra of AB(Bn_-xCl_x)₃ perovskite semiconductor film prepared on quartz substrates with excitation wavelength is indicative of their UV- Vis spectra. Figure 17 represents the quadratic behavior of the bandgap of AB(Br i- _xClx)3perovskite seriesvstheCl composition and fitted (Red solid line) using second order polynomial to determine the bowing parameter. The inset shows PLQE vsCl composition.

Figure 18 represents Lattice parameter as a function of CI composition of AB(Bri- xClx) series and fitted (red solid line) with straight line.

Figure 19 represents Absorbance spectra of AB(Ii_-xBr_x)3 series using different-Br/I ratio to tune the band gap from 2.2 eV (green) 1.6 eV (NIR).

Figure 20represents Photoluminescence of AB(li_-xBr_x)3 series using differentBr/I ratio to tune the band gap from 2.2 eV (green) 3.1 eV (UV).

Figure 21 represents Bandgapvs Br composition of AB(Ii-xBr_x)3 series and fitted (Red solid line) using second order polynomial to determine bowing parameter.

Figure 22 represents Lattice parameter vs Br composition of AB(Bri_-xCl_x) series and fitted (red solid line) with straight line. Figure 23 represents Electroluminescence (EL) spectra of perovskite materials using ITO/HIL/Perovskite/EIL/metal electrode.

Figure 24 represents J-V-L characteristics of blue emitting perovskite ITO/PEDOT:PSS/ABBrl .08C11.92/PCBM/Ag and inset image of working blue PeLED.

Figure 25 represents Cd/A vs Voltage (solid circle) and EQE vs Voltage (open circle) of ITO/PEDOT:PSS/ABBrl .08C11.92/PCBM/Ag PeLED. Figure 26 represents J-V-Lcharacteristicsof blue emitting perovskite ITO/PEDOT:PSS/ABBrl.08C11.92/PCBM/Ag and inset image of working blue PeLED inside the figure.

Figure 27 represents Cd/A vs Voltage (solid circle) and EQE vs Voltage (open circle) of ITO/PEDOT:PSS/ABBr 1.08C11.92/PCBM/Ag PeLED.

Figure 28 represents J-V-L characteristics of blue emitting perovskite ITO/PEDOT:PSS/ABBrl .08C11.92/Ag and inset image of working blue PeLED inside the figure.

Figure 29 represents J-V-L of blue emitting perovskite ITO/PEDOT:PSS/ABBr 1.08C11.92/Ag PeLED. Figure 30 represents J-V-L characteristics of ITO/PEDOT:PSS/TPD/ABBr₃/Ag and inset image of a working green PeLED inside the figure.

Figure 31 represents Cd/A vs Voltage (empty circle) and EQE vs Voltage (solid circle) of ITO/PEDOT:PSS/TPD/ABBr3/Ag PeLED.

Figure 32 represents J-V-L of ITO/PEDOT:PSS/ABBrl.87C11.17/Ag PeLED .

Figure 33 represents Cd/A vs Voltage (empty circle) and EQE vs Voltage (solid circle) of ITO/PEDOT:PSS/TPD/ABBrl .87C11.17/Ag PeLED.

Figure 34 represents J-V-L of ITO/PEDOT:PSS/ABI1.25Brl .75/Ag and the inset image of a working red PeLED inside the figure.

Figure 35 represents Cd/A vs Voltage (empty circle) and EQE vs Voltage (solid circle) of ITO/PEDOT:PSS/TPD/ABIl .25Brl .75/Ag PeLED. Figure 36. represents J-V (solid circle) and Radiance vs voltage for ITO/PEDOT:PSS/ABI3-xClx/PCBM/Ag diode.

Figure 37a and 37b shows photoluminance spectra of perovskites film with various interfaces of charge transporting layers with respect to wavelength and energy, respectively.

Figure 38 represents absorbance, photoluminescence and electroluminescence measurements on energy and wavelength scales. The inset in forth quadrant of figure shows blue shifted EL with respect to higher injection current.

Figure 39 represents (a) J-V-L characteristics, (b) luminance (solid) and power efficiency (open) vs applied bias, (c) luminance efficiency versus bias voltage and (d) external quantum efficiency vs. bias voltage for perovskite LED with structure of ITQ/Ti02/Al203/CH₃NH3PbClBr/P₃HT/Au.Device area is 4.5 mm². Light emission peak wavelength is 680 nm.

Figure 40 wherein the four graphs represents J-V-L characteristics, luminance (solid) and power efficiency (open), luminance efficiency vs, bias voltage and external quantum efficiency vs. bias voltage for perovskite LED with device structure of ITO/ZnO/Ba(OH)₂/CH3NH3PbClBr/P₃HT/Au. The device area in the contention is 4.5 mm². Thelight emission peak wavelength is 680 nm.

Figure 41 represents wherein the four graphs represents (a) I-V-L characteristics, (b) luminance (solid) and power efficiency (open) vs bias voltage, (c) luminance efficiency vs. bias voltage and (d) external quantum efficiency vs. bias voltage for perovskite LED (ITO/Ti0₂/ Al₂0₃/CH₃NH3PbClBr/Mo03/Au). Device area is 4.5 mm². Light emission peak wavelength is 680 nm.

Figure 42 represents J-V-L characteristics of mixed perovskite of different diodes fabricated on same substrate with device structure of ITO/PEDOT:PSS/CH3NH₃PbI_xCli-x/PCBM/Ag. Light emission peak wavelength is 780 nm.

Figure 43 represents external quantum efficiency (EQE) for mixed perovskite LED in ITO/PEODT: PSS/Perovskite (CH₃NH₃PbIxCl3x)/PCBM/Ag structure for different diodes on same substrate. Light emission peak wavelength is 780 nm.

Figure 44 represents external quantum efficiency (EQE) versus current density for mixed perovskite LEDs in ITO/PEODT: PSS/Perovskite (CH₃NH₃PbI_xCl₃x)/PCBM/Ag structure^' for different diodes on same substrate.

It has been therefore established that four different 3D organo-metallic halide-based perovskite semiconductors with band gaps varying from NIR to visible at room temperature that has been described in the above invention is highly advantageous as they are in their 3D crystalline forms. Furthermore, the PeLEDs of the varied band gap described above have great potential in display devices and solid state lighting applications.

Claims

WE CLAIM:

1. A photonic device for electroluminescence application, comprising: a n-type region, wherein the n-type comprises at least one n-type layer for electron injection; a p-type region wherein the p-type comprises at least one p-type layer for hole injection; a perovskite semiconductor film layer disposed between the n-type region and the p-type region, wherein the perovskite semiconductor film layer is made of an organo-metallic halide and is tuned to a band gap, wherein the band gap varies from NIR to visible range at room temperature; and at least two inter layers, the at least two inter layers incorporated between the p- type region and perovskite semiconductor film layer and the n-type region and perovksite semiconductor film layer.

2. The photonic device as claimed in claim 1 , wherein the perovskite semiconductor film layer is a mixed halide represented by a formula ABX3, wherein A is a first cation, B is a second cation and X is an anion.

3. The photonic device as claimed in claim 2, wherein the first cation is represented by a formula R-NH3, wherein R is an alkyl group or aromatic group or a monovalent metal cation..

4. The photonic device as claimed in claim 2, wherein the perovskite semiconductor film layer comprises at least one anion selected from the group of I, CI, Br and F.

5. The photonic device as claimed in claim 2, wherein the perovskite is a mixed- anion perovskite comprising two or more different anions selected from the group of I, CI, Br and F.

6. The photonic device as claimed in claim 2, wherein the second cation is a divalent metal cation selected from the group of Cu²⁺, Ni²⁺, Co²⁺, Fe²⁺, Mn²⁺,

Pd²⁺, Cd²⁺, Ge²⁺, Sn²⁺, Pb²⁺ and Eu²⁺ .

7. The photonic device as claimed in claim 1, wherein the p-type layer is selected from a group of organic conducting polymer, inorganic semiconductor and organic semiconducting material.

8. The photonic device as claimed in claim 1, wherein the n-type layer is selected from a group of organic conducting polymer, inorganic semiconductor and organic semiconducting material.

9. The photonic device as claimed in claim 1, further comprises a first electrode in contact with the n-type region and a second electrode in contact with the p-type region.

10. The photonic device as claimed in claim 1, wherein the first electrode is a metallic reflective electrode.

1 1. The photonic device as claimed in claim 1, wherein the second electrode is a transparent material electrode.

12. The photonic device as claimed in claim 1, wherein the perovskite semiconductor has a band gap varying between the ranges of 1.6 eV to 2.2 eV.

13. The photonic device as claimed in claim 1, wherein the perovskite semiconductor has a band gap varying between the ranges of 2.2 eV to 3.1 eV.

14. The photonic device as claimed in claim 1, wherein the photonic device is applied in an electrical injection laser.

15. The photonic device as claimed in claim 1, wherein the photonic device is a light emitting diode.

16. A method of preparing a photonic device for electroluminescence application, comprising the steps of: synthesizing a precursor followed by preparing of a perovskite solution using the precursors; preparing a substrate including cleaning of the substrate; and fabricating the photonic device using a perovskite semiconductor layer formed from the perovskite solution.

17. The method of preparing the photonic device as claimed in claim 16, wherein the fabricating step further comprises the steps: depositing a hole injection/p-type layer on the substrate by spin coating followed by annealing the hole injection layer/p-type layer under constant nitrogen flow, to form a sample; transferring the sample in to a nitrogen filled glove box; disposing the perovskite precursor solution by spin coating, using the precursor to form a dense film of the perovskite semiconductor layer; depositing an electron injection layer/n-type layer on the perovskite semiconductor layer by spin coating; and depositing an electrode on the electron injection layer/n-type layer by evaporation technique.

18. The method as claimed in claim 16, wherein the method of disposing of the perovskite semiconductor layer can be selected from a group of chemical vapor deposition (CVD), thermal evaporation, dip coating method, PLD (Plus Laser Deposition), drop casting method and LPE (Liquid Phase epitaxy).

19. The method as claimed in claim 16, wherein the perovskite semiconductor layer is tunable to band gap varying from NIR to visible range at room temperature.

20. The method as claimed in claim 16, where the photonic device comprises: a n-type region, wherein the n-type comprises at least one n-type layer for electron injection; a p-type region wherein the p-type comprises at least one p-type layer for hole injection;

a perovskite semiconductor film layer disposed between the n-type region and the p-type region, wherein the perovskite semiconductor film layer is made of an organo-metallic halide and is tuned to a band gap, wherein the band gap varies from NIR to visible range at room temperature; and

at least two inter layers, the at least two inter layers incorporated between the p- type region and perovskite semiconductor film layer and the n-type region and perovksite semiconductor film layer.

21. The method as claimed in claim 17, wherein the perovskite is selected from a group of CHsNHsPbla-xClx, CH₃NH3Pbl3-x-yCl_xBr_y, CH₃NH₃PbBr3, CHsNtbPbCb, CH3NH3Pb(I_{1 -x}Br_x)₃ and CH₃NH3Pb(Bri-_xCl_x)₃

22. The method as claimed in claim 20, wherein the n-type layer is selected from a group of Zinc oxide (ZnO), PCBM, PC₆iBM and PC71BM.

23. The method as claimed in claim 20, wherein the p-type layer is selected from a group of PEDOT:PSS, Spiro-MeOTAD(2,2',7,7'-tetrakis(N,N- dipmethoxyphenylamine)9,9spirobifluorene), P3HT(poly(3hexylthiophene-2,5- diyl)),DEH(4-(diethylamino)-benzaldehydediphenylhydrazone), PCPDTBT (Poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2, 1 -b;3,4-b']dithiophene)-alt- 4,7(2, 1,3-benzothiadiazole), PCDTBT(Poly[N-9'-heptadecanyl-2,7-carbazole-alt- 5,5-(4',7'-di-2-thienyl-2^*, 1 ',3'-benzothiadiazole), PTAA (Polybis(4-phenyl)(2,4,6- trimethylphenyl)amine), Nickel tri oxide (N1O3) and Molybdenum tri oxide(MoC>3).

24. The method as claimed in claim 17, wherein annealing of the p-type layer is carried out at a temperature of 150 ⁰ C for a duration of 30 minutes.

25. The method as claimed in claim 17, wherein the disposing of the precursor solution is followed by annealing at a temperature of 100 ⁰ C for a duration of 15 minutes.

26. The method as claimed in claim 17, wherein the depositing of the electrode by evaporation technique is carried out in lxlO^mbar vacuum at room temperature.

27. The method as claimed in claim 17, wherein the electrode can be selected from a group of Au, Ag and Al.