HYBRID TIN-BASED PEROVSKITE SOLAR CELLS ON PIEZOELECTRIC FLEXIBLE SUBSTRATES

Abstract

The present disclosure relates to a solar device (100) that includes a transparent substrate (102) on which a hybrid organic-inorganic metal halide perovskite is fabricated. A conductive layer (104) deposited onto the transparent substrate, serves as bottom electrode. A hole transport layer (106) is accommodated on top of the conductive layer to assist in movement of positive holes. A photoactive layer (108) is disposed of on top of the hole transport layer. An electron transport layer (110) is disposed between a top electrode and the photoactive layer to facilitate the transport of electrons generated in the photoactive layer to the electrode and an interfacial material (112) is disposed between the top electrode and the electron transport layer to enhance performance of the solar device

Specification

Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to photovoltaic devices, and more specifically, relates to a solar cell that incorporates lead-free perovskite materials and utilizes flexible substrates for enhanced performance and adaptability in energy conversion applications.

BACKGROUND
[0002] Solar cells have emerged as a technology to convert sunlight directly into electricity in response to the increasing need for sustainable and renewable sources of energy. Fossil fuels, including coal, oil, and natural gas, have long been the dominant sources of energy, but their use has raised environmental and health concerns such as air pollution, greenhouse gas emissions, and climate change. Solar cells offer a clean and renewable alternative to traditional energy sources, as they do not emit pollutants or greenhouse gases during operation. Furthermore, solar cells possess modularity, scalability, and portability, rendering them suitable for a wide range of applications, including small-scale consumer electronics and large-scale power plants.
[0003] Solar cells are categorized into three generations, with the first-generation solar cells comprising crystalline silicon and representing the most widely utilized type of solar cells. These crystalline silicon solar cells exhibit the highest efficiency among the various generations; however, they are also the most costly to manufacture due to the need for high-purity silicon and complex production processes. To address the limitations of crystalline silicon solar cells, second-generation solar cells, also known as thin-film solar cells, were developed. These thin-film solar cells are composed of materials such as cadmium telluride, copper indium gallium selenide (CIGS), and amorphous silicon, and are less expensive to produce compared to first-generation solar cells, though they exhibit lower efficiency. In response to the challenges of high production costs and low power conversion efficiency inherent in the first and second generations of solar cells, third-generation solar cells were introduced, incorporating a variety of innovative materials. The emerging third-generation solar cells include perovskite, organic, and quantum dot solar cells, offering advancements in performance and potential applications.
[0004] Several existing technologies have made advancements in the preparation and material composition of perovskite solar cells. For example, Chinese patent CN104134711A discloses a solution-based preparation method for perovskite solar cells, using low-temperature (below 200°C) processing for fabricating the electron transfer layer, the perovskite material light absorption layer, and the hole transfer layer. This approach simplifies the fabrication process and reduces manufacturing costs. However, the materials and techniques employed do not account for flexibility, which is increasingly in demand for solar cells used in curved or flexible environments.
[0005] In other technologies, such as those described in WO2015160838A1 and US11222924B2, hybrid organic-inorganic perovskite compounds and flexible substrates have been explored. However, these solutions typically rely on methylammonium lead halide perovskites, which pose toxicity concerns due to the use of lead. Additionally, the substrates used in these devices, such as glass and PETG, may lack sufficient flexibility or durability for certain applications. Furthermore, the perovskite materials often require additional complex processing steps for their preparation, which can increase manufacturing costs and reduce scalability.
[0006] Therefore, it is desired to overcome the drawbacks, shortcomings, and limitations associated with existing solutions, and develop a perovskite solar cell with an improved material composition and fabrication process. Specifically, the development of a lead-free perovskite material, combined with a flexible, piezoelectric polymer substrate can contribute to energy generation through nanogeneration. The present disclosure would not only enhance the photovoltaic efficiency of the cell but also increase its flexibility, durability, and potential for large-scale production.




OBJECTS OF THE PRESENT DISCLOSURE
[0007] An object of the present disclosure is to provide a device that utilizes a lead-free perovskite material to enhance environmental safety and reduce toxicity concerns associated with conventional solar cells.
[0008] Another object of the present disclosure is to provide a device that features a flexible polyvinylidene fluoride (PVDF) substrate, facilitating lightweight and adaptable solar modules suitable for various applications, including curved surfaces.
[0009] Another object of the present disclosure is to provide a device wherein the PVDF substrate functions as a piezoelectric nanogenerator, allowing simultaneous solar energy conversion and mechanical energy harvesting.
[0010] Another object of the present disclosure is to provide a device that simplifies the manufacturing process by employing a hot injection method for synthesizing perovskite material and sputtering techniques for preparing transport layers, thereby enhancing production efficiency and reducing costs.
[0011] Another object of the present disclosure is to provide a device that achieves improved power conversion efficiency through the utilization of formamidinium tin iodide (FASnI3) as the photoactive material, surpassing the performance of traditional materials.
[0012] Yet another object of the present disclosure is to provide a device that incorporates silver as the top electrode, ensuring superior conductivity and durability compared to conventional transparent conductive materials.

SUMMARY
[0013] The present disclosure relates in general, to photovoltaic devices, and more specifically, relates to a solar cell that incorporates lead-free perovskite materials and utilizes flexible substrates for enhanced performance and adaptability in energy conversion applications. The main objective of the present disclosure is to overcome the drawbacks, limitations, and shortcomings of the existing device and solution, by providing photovoltaic materials that have been extensively explored over the past decade for clean and renewable solar energy conversion, with particular emphasis on perovskite solar cells that are of significant interest within the solar cell community due to their low processing costs, ease of fabrication, and superior power conversion efficiencies that surpass those of traditional silicon cells. However, perovskite materials are susceptible to degradation when exposed to moisture, heat, and ultraviolet (UV) radiation, leading to diminished power conversion efficiency and a reduction in the overall lifespan of the solar cells. To address these challenges, halide-based hybrid perovskites have demonstrated enhanced stability in comparison to other perovskite materials. Additionally, hybrid organic-inorganic halide perovskite solar cells have been introduced, offering improved stability and reduced toxicity relative to pure inorganic perovskites. Although lead-based hybrid perovskite solar cells have achieved higher efficiencies, their toxicity presents significant concerns. To mitigate this toxicity, inorganic metals have been substituted with tin. Furthermore, highly efficient organic-inorganic hybrid perovskite solar cells have been fabricated on a flexible substrate composed of polyvinylidene fluoride (PVDF), catering to the increasing demand for flexible and bendable power sources. Polyvinylidene fluoride, a polymer material exhibiting piezoelectric properties, can generate power at the nano-level, thus enabling the utilization of the PVDF substrate both as a foundation for photovoltaic devices and as a nanogenerator.
[0014] The solar device is disclosed comprising a transparent substrate on which a hybrid organic-inorganic metal halide perovskite is fabricated. A conductive layer is deposited onto the transparent substrate, serving as a bottom electrode and comprising a transparent conductive material to facilitate the transfer of electrons. A hole transport layer is accommodated on top of the conductive layer to assist in the movement of positive holes within the solar cell. A photoactive layer is disposed on top of the hole transport layer, wherein the hole transport layer is positioned between the bottom electrode and the photoactive layer to facilitate the transport of holes generated in the photoactive layer to the electrode. An electron transport layer is disposed between a top electrode and the photoactive layer to facilitate the transport of electrons generated in the photoactive layer to the electrode, with the top electrode being deposited on the electron transport layer to operate as a positive terminal. Additionally, an interfacial material is disposed of between the top electrode and the electron transport layer to enhance the performance of the solar device. The transparent substrate may be made of a polymer, such as poly(vinylidene fluoride) (PVDF), which can be flexible, enabling the solar device to operate as a nanogenerator. The transparent conductive material can be fluorine-doped tin oxide (FTO). The hole transport layer may comprise a conductive polymer blend made of poly(3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT). The photoactive layer can include a metal halide perovskite compound having the formula ABX3, where A is a monovalent organic cation (formamidinium cation (FA)), B is a tin metal cation (Sn), and X is an iodide anion (I). The electron transport layer can be made of Buckminsterfullerene (C60) or a derivative of fullerene. The top electrode may be made of gold or silver.
[0015] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0017] FIG. 1A to FIG. 1C illustrates an exemplary view of solar cell module, in accordance with an embodiment of the present disclosure.
[0018] FIG. 2 illustrates an exemplary fabrication of a solar cell module, in accordance with an embodiment of the present disclosure.




DETAILED DESCRIPTION
[0019] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature "may", "can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0020] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
[0021] The present invention provides a hybrid tin halide perovskite solar cell that emerges as a viable alternative to traditional silicon-based solar cells due to its high efficiency and low production costs. Tin-based perovskites offer several advantages over their lead-based counterparts, including reduced toxicity and enhanced environmental friendliness. Additionally, tin-based perovskites feature a wider bandgap, enabling them to absorb a broader spectrum of light wavelengths, thereby resulting in improved efficiency. Furthermore, the present invention discloses a flexible large-area perovskite solar cell module that incorporates nanogeneration capabilities. The solar cell module comprises a transparent substrate on which the solar cells are embedded, featuring a conductive layer that serves as a bottom electrode, onto which a hole transport layer, a perovskite material, and an electron transport layer are sequentially deposited. The conductive layer situated over the transparent substrate functions as the bottom electrode, while a metal layer positioned atop the solar cell acts as the top electrode. The remaining area of the flexible transparent substrate functions as a nanogenerator due to the piezoelectric properties of the substrate material, providing an additional power output that complements the energy generated by the solar cell.
[0022] The solar device is disclosed comprising a transparent substrate on which a hybrid organic-inorganic metal halide perovskite is fabricated. A conductive layer is deposited onto the transparent substrate, serving as a bottom electrode and comprising a transparent conductive material to facilitate the transfer of electrons. A hole transport layer is accommodated on top of the conductive layer to assist in the movement of positive holes within the solar cell. A photoactive layer is disposed on top of the hole transport layer, wherein the hole transport layer is positioned between the bottom electrode and the photoactive layer to facilitate the transport of holes generated in the photoactive layer to the electrode. An electron transport layer is disposed between a top electrode and the photoactive layer to facilitate the transport of electrons generated in the photoactive layer to the electrode, with the top electrode being deposited on the electron transport layer to operate as a positive terminal. Additionally, an interfacial material is disposed of between the top electrode and the electron transport layer to enhance the performance of the solar device. The transparent substrate may be made of a polymer, such as poly(vinylidene fluoride) (PVDF), which can be flexible, enabling the solar device to operate as a nanogenerator. The transparent conductive material can be fluorine-doped tin oxide (FTO). The hole transport layer may comprise a conductive polymer blend made of poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT). The photoactive layer can include a metal halide perovskite compound having the formula ABX3, where A is a monovalent organic cation (formamidinium cation (FA)), B is a tin metal cation (Sn), and X is an iodide anion (I). The electron transport layer can be made of Buckminsterfullerene (C60) or a derivative of fullerene and the interfacial material made of Bathocuproine (BCP). The top electrode may be made of gold or silver. The present disclosure can be described in enabling detail in the following examples, which may represent more than one embodiment of the present disclosure.
[0023] The advantages achieved by the device of the present disclosure can be clear from the embodiments provided herein. The device incorporates a lead-free perovskite material, thereby eliminating the environmental and toxicity concerns associated with conventional lead-based perovskite solar cells. Additionally, the present disclosure provides a device that utilizes a flexible polyvinylidene fluoride (PVDF) substrate, enabling the fabrication of lightweight and flexible solar modules suitable for curved and portable applications. Furthermore, the present disclosure provides a device where the PVDF substrate serves as a piezoelectric nanogenerator, allowing for the dual function of solar energy conversion and mechanical energy harvesting. Moreover, the present disclosure provides a device with a simplified manufacturing process, utilizing a hot injection method for synthesizing perovskite material and sputtering techniques for preparing transport layers, thereby reducing manufacturing complexity and production costs. In addition, the present disclosure provides a device with enhanced power conversion efficiency through the use of formamidinium tin iodide (FASnI3) as the photoactive material, which offers improved energy conversion and stability compared to conventional materials. The present disclosure provides a device that employs silver as the top electrode, which offers superior conductivity and durability when compared to conventional transparent conductive materials.
[0024] The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0025] FIG. 1A to FIG. 1C illustrates an exemplary view of solar cell module, in accordance with an embodiment of the present disclosure.
[0026] Referring to FIG. 1A to FIG. 1C, a solar cell module 100 (also referred to as solar device 100, herein) for fabricating flexible, lead-free hybrid perovskite solar cells is disclosed. The device 100 includes a transparent substrate 102, a conductive layer 104, a hole transport layer 106, a lead-free hybrid perovskite material 108, an electron transport layer 110, an interfacial layer 112, and a top electrode 114. FIG. 1A is a top view of the solar cell module, FIG. 1B is an angular view of the solar cell module, and FIG. 1C depicts the flexibility of the solar cell.
[0027] The transparent substrate 102 is made of poly(vinylidene fluoride) (PVDF) polymer, known for its flexibility, high strength-to-weight ratio, and piezoelectric properties. The flexible substrate material on which the hybrid organic-inorganic metal halide perovskite is fabricated. The substrate 102 on which the photovoltaic cell is fabricated can include a polymer material. In one embodiment, the polymer substrate material is polyvinylidene fluoride (PVDF), a member of the class of materials known as fluoropolymers. The PVDF-based polymer substrate further functions as a nanogenerator, providing additional power generation capabilities. Additionally, the PVDF substrate imparts flexibility to the photovoltaic cell, enabling the solar module to be flexible and adaptable for various applications.
[0028] The conductive layer 104, deposited onto the PVDF substrate, serves as the bottom electrode and facilitates the transfer of electrons. The bottom electrode can include electrically conductive material. The bottom electrode can include a transparent conductive material, where the transparent conductive material of the conductive layer 104 is fluorine-doped tin oxide (FTO).
[0029] The hole transport layer 106 is applied on top of the conductive layer 104 to assist in the efficient movement of positive charges (holes) within the solar cell. The hole transporting material of the hole transport layer 106 is Poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT:PSS). The hole transporting material includes a conductive polymer blend. The hole transporting layer 106 disposed between the bottom conductive electrode and the photoactive material, configured to facilitate the transport of holes generated in the photoactive material to the electrode.
[0030] A photoactive layer 108 can include a metal halide perovskite compound having the formula FASnI3, wherein FA is a Formamidinium cation, Sn is a Tin metal cation and I3 is an Iodide anion. The photoactive material disposed between charge transporting materials, wherein the photoactive material comprises a metal halide perovskite compound of formula ABX3, wherein A represents a monovalent organic cation, B represents an inorganic metal cation, and X represents a halide. In one embodiment, the A cation in the metal halide perovskite compound is a formamidinium cation (FA). In another embodiment, the B cation in the metal halide perovskite compound is a tin metal cation (Sn). Further, the X anion in the metal halide perovskite compound represents an iodide anion (I).
[0031] The electron transport layer 110 is then applied on top of the perovskite material, facilitating the flow of electrons to the top electrode. The electron transporting layer 108 disposed between the top electrode and the photoactive material, configured to facilitate the transport of electrons generated in the photoactive material to the electrode. The electron transporting material is Buckminsterfullerene (C60). The electron-transporting material of the electron transport layer 108 comprises a derivative of fullerene. An interfacial layer 112 made of material (Bathocuproine - BCP) to further improve the performance
[0032] The top electrode 114, typically made of a metal like gold or silver, is deposited on the electron transport layer 108 and functions as the positive terminal of the solar cell. The leftover areas of the flexible PVDF substrate, not occupied by the solar cell structure, act as a nanogenerator, utilizing the piezoelectric properties of PVDF. This allows the device to generate additional electric power through mechanical stress or movement, thereby enhancing the overall energy output of the solar cell.
[0033] The formamidinium tin halide-based perovskite solar cell is a non-toxic photovoltaic device characterized by enhanced stability and a temperature tolerance of up to 120 degrees Celsius, achieving a power conversion efficiency of approximately 15%. Furthermore, when these solar cells are fabricated on a piezoelectric polyvinylidene fluoride (PVDF) substrate with dimensions of 2 cm x 2 cm x 200 μm to form solar cell modules, the vacant space between the cells functions as a nanogenerator, generating an open circuit peak-to-peak voltage of around 15V.
[0034] The flexible hybrid perovskite solar cell is highly efficient, stable, and non-toxic. The combination of the PVDF substrate's flexibility and its nanogenerator functionality makes the device particularly suitable for applications in portable and wearable devices. The use of poly(vinylidene fluoride) enables the fabrication of a flexible solar cell that not only converts sunlight into electrical energy but also generates power from mechanical movements, broadening its potential for sustainable energy solutions.
[0035] Perovskites are materials represented by the formula ABX3, where X is an anion and A and B are cations of differing sizes, with A being larger than B. The larger A cation occupies a cuboctahedral site shared with twelve X anions, while the smaller B cation is positioned in an octahedral site shared with six X anions. The most extensively studied perovskites are oxides due to their electrical properties, including ferroelectricity and superconductivity. Halide perovskites initially garnered limited attention until layered organometal halide perovskites demonstrated a semiconductor-to-metal transition with increased dimensionality. Notably, with the increase in dimensionality from two-dimensional (2D) to three-dimensional (3D), electrical properties changed, and the band gap decreased, making the material more suitable for solar cell applications. The foundational technology for perovskite solar cells stems from solid-state-sensitized solar cells, which in turn are based on dye-sensitized solar cell designs. Over recent years, perovskite solar cells have demonstrated rapid advancements, achieving power conversion efficiencies approaching 26%, which is comparable to the best silicon-based solar cells.
[0036] Despite this promising performance, perovskite solar cells encounter challenges such as long-term durability, which limits their competitiveness with established technologies. To address these challenges, hybrid perovskite materials have enabled significant improvements in both material and device stability. Among these hybrid perovskite solar cells, the combination of organic and inorganic perovskite materials has exhibited a high-power conversion efficiency that surpasses that of traditional silicon solar cells. Organic-inorganic hybrid perovskite solar cells have shown remarkable improvement in power conversion efficiency over the past eight years, earning them recognition as a "miracle photovoltaic material.
[0037] Methylammonium lead halides (MAPbX3, where X = I, Cl, Br) are the most thoroughly studied perovskite materials due to their high energy conversion efficiency and low fabrication cost, with MAPbI3 possessing an optical direct band gap of 1.55 eV and light absorption across the visible spectrum. The inorganic metal in hybrid organic-inorganic perovskites is typically lead (Pb), which offers favorable efficiency and stability. However, the toxic and environmentally hazardous nature of lead has necessitated the development of lead-free perovskite solar cell materials, which exhibit similar crystal structures to lead-based hybrids and offer comparable efficiency and stability.
[0038] Furthermore, replacing the A-site cation with formamidinium (FA+) has emerged as a preferred choice, resulting in a more closely packed structure and a lower band gap of 1.48 eV, with an absorption edge at 840 nm, compared to MAPbI3. FAPbI3 exists in two distinct phases, α-FAPbI3 (black) and δ-FAPbI3 (yellow), with the α-phase exhibiting a perovskite structure and the δ-phase representing a non-perovskite structure. The non-perovskite δ-phase is more thermodynamically stable in ambient atmospheres with high moisture content, whereas the transition to the α-FAPbI3 perovskite phase occurs only at temperatures above 140°C.
[0039] FIG. 2 illustrates an exemplary fabrication of a solar cell module, in accordance with an embodiment of the present disclosure. The method for device fabrication, characterization, and testing, which comprises the following steps:
[0040] Substrate Preparation: This involves preparing 202 a suitable substrate, such as a piezoelectric or flexible polymer substrate, for the device. The substrate is processed through compression molding, a technique where high pressure and heat are applied to shape the material into the required form. Compression molding ensures that the substrate is uniform and durable for the subsequent layers of material to be deposited.
[0041] Synthesis of Chemicals: In this step, the chemicals 204 required for device fabrication are synthesized using techniques such as the hydrothermal method and hot injection method.
• Hydrothermal Method: A technique that involves crystallizing substances from high-temperature aqueous solutions at high vapor pressures. This method is particularly useful for producing nanomaterials.
• Hot Injection Method: This involves injecting a hot solution of reactants into a cold solvent, initiating rapid nucleation and growth of particles. This method is often used for synthesizing nanoparticles or quantum dots with controlled size and shape.
[0042] Fabrication of the Device: The synthesized chemicals are then used to fabricate 206 the device using one or more of the following deposition techniques:
• Spin Coating: A technique where a solution of the active material is deposited onto the substrate by rotating it at high speed, which spreads the solution evenly across the surface. Spin coating is typically used for creating thin films.
• Sputtering: A physical vapor deposition process where a target material is bombarded with high-energy particles, causing atoms from the target to be ejected and deposited onto the substrate, forming a thin film.
• Electron Beam (E-beam) Evaporation: A vacuum deposition method where an electron beam is used to heat a material until it evaporates and is then deposited onto the substrate in a controlled manner, forming a uniform layer.
[0043] Characterization of the Device: Once the device is fabricated, it is subjected to various characterization techniques 208 to ensure its structural, morphological, optical, and thermal properties meet the desired specifications:
• Structural Analysis: This includes techniques such as:
• X-ray Diffraction (XRD) to examine the crystallographic structure.
• X-ray Photoelectron Spectroscopy (XPS) to study the elemental composition and chemical state of the materials.
• Raman Spectroscopy to analyze vibrational modes of the molecules, providing insights into the molecular structure.
• Morphology Analysis: Using Field Emission Scanning Electron Microscopy (FESEM), the surface and microstructure of the material are examined at very high resolutions to ensure the device's surface morphology is uniform.
• Optical Analysis: This step includes the use of UV-Vis spectroscopy to study the optical absorption properties, photoluminescence to assess light emission, and Time-Correlated Single Photon Counting (TCSPC) or Time-Resolved Photoluminescence (TRPL) to measure the lifetimes of excited states in materials.
• Thermal Analysis: The device is analyzed using Thermogravimetric Analysis (TGA) or Thermogravimetric-Differential Thermal Analysis (TGDTA) to study its thermal stability, measuring changes in weight as the material is heated and cooled.
[0044] Testing of the Device: After characterization, the device undergoes performance testing 210:
• Solar Cell Characteristics: A solar simulator is used to simulate sunlight under controlled conditions, allowing for the measurement of the solar cell's power conversion efficiency, short-circuit current, and open-circuit voltage.
• I-V Measurements: A source meter is used to perform current-voltage (I-V) measurements, which are critical for determining the electrical properties of the device, such as its resistance, efficiency, and other performance metrics.
[0045] Demonstration of the Device: Finally, the fabricated and tested device is demonstrated 212 to verify its operational capabilities in a practical setting, ensuring that the device meets the necessary performance criteria and can be utilized in real-world applications.
[0046] The present disclosure provides a non-toxic formamidinium tin halide-based perovskite solar cell, exhibiting enhanced stability and capable of withstanding temperatures up to approximately 120 degrees Celsius. The power conversion efficiency of the solar cell is approximately 15%. Further, when fabricated on a piezoelectric PVDF substrate of dimensions 2cm x 2cm x 200μm, the solar cells are arranged to form solar cell modules, wherein the vacant space between the cells operates as a nanogenerator, generating an open circuit peak-to-peak voltage of approximately 15V.
[0047] It will be apparent to those skilled in the art that the device 100 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT INVENTION
[0048] The present disclosure provides a device that incorporates a lead-free perovskite material, thereby eliminating the environmental and toxicity concerns associated with conventional lead-based perovskite solar cells.
[0049] The present disclosure provides a device that utilizes a flexible polyvinylidene fluoride (PVDF) substrate, enabling the fabrication of lightweight and flexible solar modules suitable for curved and portable applications.
[0050] The present disclosure provides a device where the PVDF substrate serves as a piezoelectric nanogenerator, allowing for the dual function of solar energy conversion and mechanical energy harvesting.
[0051] The present disclosure provides a device with a simplified manufacturing process, using a hot injection method for synthesizing perovskite material and sputtering techniques for transport layers, reducing complexity and production costs.
[0052] The present disclosure provides a device with enhanced power conversion efficiency through the use of formamidinium tin iodide (FASnI3) as the photoactive material, which offers improved energy conversion and stability over conventional materials.
[0053] The present disclosure provides a device that employs silver as the top electrode, offering superior conductivity and durability compared to conventional transparent conductive materials.
, Claims:1. A solar device (100) with hybrid tin-based perovskite solar cells on piezoelectric flexible substrates, the device comprising:
a transparent substrate (102) on which a hybrid organic-inorganic metal halide perovskite is fabricated;
a conductive layer (104) deposited onto the transparent substrate, serves as bottom electrode comprising transparent conductive material to facilitate transfer of electrons;
a hole transport layer (106) accommodated on top of the conductive layer to assist in movement of positive holes within solar cell;
a photoactive layer (108) disposed on top of the hole transport layer, wherein the hole transport layer disposed between the bottom electrode and the photoactive layer to facilitate the transport of holes generated in the photoactive layer to the electrodes;
an electron transport layer (110) disposed between a top electrode and the photoactive layer to facilitate the transport of electrons generated in the photoactive layer to the electrode, wherein the top electrode (114) is deposited on the electron transport layer to operate as a positive terminal; and
an interfacial material (112) disposed between the top electrode and the electron transport layer to enhance performance of the solar device.
2. The device as claimed in claim 1, wherein the transparent substrate (102) is made of a polymer.
3. The device as claimed in claim 2, wherein the polymer is poly(vinylidene fluoride) (PVDF) polymer.
4. The device as claimed in claim 1, wherein the transparent substrate (102) is flexible, enabling the solar device to operate as a nanogenerator.
5. The device as claimed in claim 1, wherein the transparent conductive material is Fluorine-doped Tin Oxide (FTO).
6. The device as claimed in claim 1, wherein the hole transport layer (106) comprises a conductive polymer blend made of Poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT:PSS).
7. The device as claimed in claim 1, wherein the photoactive layer (108) comprising a metal halide perovskite compound having formula ABX3, wherein A is a monovalent organic cation, B is an inorganic metal, and X represents the halide, with A being formamidinium cation (FA), B being a tin metal cation (Sn) and X representing iodide anion (I).
8. The device as claimed in claim 1, wherein the electron transport layer (110) is made of Buckminsterfullerene (C60) and the interfacial material is made of Bathocuproine (BCP)
9. The device as claimed in claim 1, wherein the electron transport layer comprises a derivative of fullerene.
10. The device as claimed in claim 1, wherein the top electrode (114) is made of gold or silver.

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