Halide-based Perovskite Research Articles

A 0D Ge(II)-Halide-Based Perovskite with Enhanced Semiconducting Behavior for Electronic Capacitors.

Perovskite materials have surged to the forefront of materials science, captivating researchers worldwide with their distinctive crystal lattice arrangement and remarkable optical, electric and dielectric attributes. The current study focuses on the development of a novel zero-dimensional (0D) Ge(II)-based hybrid perovskite, formulated as NH3(CH2)2NH3GeF6, and synthesized through a gradual evaporation process conducted at room temperature. The crystal structure is characterized by an arrangement of organic cations and isolated octahedral [GeF6]2- groups. This configuration is stabilized by relatively weak intermolecular bonds. A comprehensive analysis of the material's thermal properties using differential scanning calorimetry (DSC) revealed a distinct phase transition occurring at approximately 323 K, which was further confirmed through electrical measurements. The studied compound provided a broad absorption range across the visible spectrum and an optical band gap of 3.30 eV, indicating its potential for semiconducting applications in optoelectronic devices. Photoluminescence PL analysis displays a blueish broad-band emission with a high color rendering index CRI value of 91, when excited at 325 nm. This emission primarily originates from the self-trapped excitons (STEs) recombination in the inorganic [GeF6]2-. Herein, the temperature-dependent behavior of grain conductivity exhibited an Arrhenius-type pattern, with an activation energy (E a) of 0.46 eV, confirming the semiconductor nature of the investigated compound. In addition, a deep investigation of the alternating current conductivity, analyzed using Jonscher's law, demonstrates that the conduction mechanism is effectively described by the correlated barrier hopping (CBH) model. The dielectric performances show a significant dielectric constant (ε' ∼ 103). Thus, all these interesting physical properties of this hybrid perovskite have paved the way for advancements in various technological applications, particularly in the field of electronic capacitors.

Simulation of perovskite solar cell with transparent contacts for solar windows

In recent years, halide-based perovskite solar cells (PSC) have caught worldwide attention since their power conversion efficiency (PCE) has surpassed 25% with low fabrication cost and high scalability. The semi-transparent PSC (ST-PSC) is suitable for building-integrated photovoltaic (BIPV) applications, especially for solar windows. The ST-PSC must demonstrate a reasonable balance between PCE and transparency in the visible region for solar windows, which is inversely proportional to each other. This work studies ST-PSC based on methylammonium lead triiodide (MAPbI3) as solar windows using the General-Purpose Photovoltaic Device Model (GPVDM) and OPAL 2 as the simulation platforms. Parameters such as methylammonium lead triiodide (MAPbI3) thickness, silver (Ag) contact thickness and indium tin oxide (ITO) transparent contact thickness are investigated in relation to the PCE and average visible transmission (AVT). The results demonstrate that the ST-PSC with MAPbI3 thickness of 500 nm and ITO bottom transparent contact of 100 nm leads to PCE of 22.85% and AVT of 11.36%. These parameters represent the best results obtained in this work.

Transparent Luminescent down-conversion coating for improved performance and enhanced stability of carbon-based perovskite solar cells

Methylammonium lead halide-based perovskite solar cells (PSCs) perform superior photovoltaic performance, nevertheless, demonstrate limited light utilization and instability within the ultraviolet (UV) range. Lanthanide-based down-conversion (DC) materials can mitigate the photoinduced deterioration by resolving spectrum mismatched losses. Particularly, lanthanide complexes possess a broad UV absorbing region thus can convert absorbed UV light to visible or near-infrared light, exhibiting large pseudo-Stoke's shift while they could allow spectrum responsiveness of the PSCs in the UV.Therefore, the DC material may enhance the photovoltaic performance by converting high-energy photons to low-energy photons whilst may also perform as UV shielding material, and finally may both develop PSCs' efficiency and stability. Herein, a novel transparent luminescent down-converting layer (LDC) based on a highly emitting Europium complex in a siloxane matrix was used as an external coating to PSCs with the purpose of improving the solar cells' performance extending their response in the UV region while improving cells’ photostability. The conducted studies indicated that the LDC coating may additionally serve as an anti-reflective and UV-shielding layer simultaneously, resulting in better light-harvesting ability of the perovskite. As a result, short circuit current (Jsc) amplification by the presence of LDC re-emitting the absorbed UV light to the visible and the best carbon-based perovskite solar cell (C-PSC) revealed a 16.13 % overall performance in comparison to the 15.38 % obtained for the control device. Furthermore, photostability tests demonstrated that the unencapsulated LDC-modified devices prepared under ambient conditions retained 75 % of their initial PCE after 8 h under artificial solar light illumination whereas the control devices remained at 40 % at the same conditions. These findings suggest that the LDC layer decreases the UV degradation for PCEs, resulting in PCE and stability enhancement.

Pressure-driven semiconducting to metallic transition in francium tin trihalides perovskite with improved optoelectronic performance: A DFT study

The objective of our study was to analyze the mechanical, magnetic, elastic, electrical, and optical characteristics of the halide-based perovskite FrSnX3 (X = Cl, Br, and I) at hydrostatic pressures ranging from 0 to 6 GPa. We conducted this analysis using first-principles calculations based on density functional theory. The thermodynamic and mechanical stability of the complex FrSnX3 (X = Cl, Br, and I) were calculated based on its formation enthalpy and elastic constant characteristics. The compound was found to be ductile and stable. FrSnCl3, FrSnBr3, and FrSnI3 are all classified as semiconductors according to band calculations. Their respective bandgaps are 1.046, 0.675, and 0.485 eV, respectively. These values remain constant when hydrostatic pressure is not applied. The bandgap and density of states of the three halides were examined to observe their variations with increasing induced pressure. The bandgaps of FrSnCl3, FrSnBr3, and FrSnI3 were measured to be 0 eV at pressures of 6, 4, and 2 GPa, respectively. In addition, a comprehensive study was conducted on the optical properties of cubic perovskites FrSnX3 (X = Cl, Br, and I) under different hydrostatic pressures ranging from 0 to 6 GPa. The investigation focused on analyzing the optical absorption, reflectivity, and refractive index, as well as the imaginary and real components of the dielectric functions. Under high pressure, the compound exhibited higher absorption capabilities for all compounds within the 10–13 eV range, transforming into a conductor. This property makes it well-suited for utilization in the UV spectrum. Chlorine exhibits the greatest absorption among all chemicals, whereas iodine demonstrates the least absorption. The reflectance values of all compounds range from 12% to 16% and increase with increasing pressure. At the energy level of zero, the refractive index’s real component ranges from 1.25 to 1.7, and it increases with increasing pressure. Chlorine has a relatively low refractive index compared to iodine. Bromine has the most pronounced variance. The dielectric characteristics typically vary from 4.5 to 7.5 F/m. As pressure increases, the charge storage capacities of all compounds increase. However, among these compounds, iodine has the highest capacity, while chlorine (Cl) has the lowest. The hydrostatic pressure applied to the structure FrSnX3 (X = Cl, Br, and I) causes it to become harder and more ductile. This is evident from the increasing values of the bulk, Young’s, and shear modulus, as well as the elastic constants (C11 and C12). We optimized the band structure and density of states by aligning the electrons in a co-linear location and assessed the magnetic properties. The diamagnetic characteristic of the FrSnX3 compound (where X = Cl, Br, and I) remained unchanged when subjected to increasing pressure. The results indicate that the perovskite material has exceptional absorption properties, indicating a change in its behavior from a transistor to a metal. The numerical findings highlight the potential applications of this material in photovoltaic cells, ultraviolet light absorbers, and optoelectronic devices.

Calculations of the mechanical, optoelectronic, and magnetic properties of FrGeX3 (X = Cl, Br, I) under hydrostatic pressures based on first-principles theories

Using first-principles calculations based on density functional theory, this work investigated the mechanical, magnetic, elastic, electrical, and optical characteristics of the halide-based perovskite FrGeX3 (X = Cl, Br, I) at different hydrostatic pressures ranging from 0 to 9 GPa. It was determined that the compound FrGeX3 (X = Cl, Br, I) is stable and ductile in nature by calculating its thermodynamic and mechanical stability using the parameters of its formation enthalpy and elastic constant. When no hydrostatic pressure is applied, the band computations reveal that FrGeCl3, FrGeBr3, and FrGeI3 all remain in the semiconductor region with bandgaps of 1.14, 0.8, and 0.645 eV, respectively. The study examined how increasing induced pressure affects the bandgap and density of states of the structure for all three halides. The bandgap of FrGeCl3, FrGeBr3, and FrGeI3 fell to 0 eV at 9, 6, and 5 GPa, respectively. In addition, the optical absorption, reflectivity, refractive index, and imaginary and real components of dielectric functions were all studied in detail for cubic perovskites FrGeX3 (X = Cl, Br, I) under varying hydrostatic pressures, from 0 to 9 GPa. Due to increased pressure, the compound transitioned into a conductor and improved its absorption capabilities for all compounds within the 8–14 eV range, making it suitable for use in the UV spectrum. Cl has the largest absorption among all compounds, whereas I displays the lowest. Reflectivity ranges from around 14% to 18% for all compounds and increases w%ith pressure. The actual component of the refractive index ranges from around 2.25 to 2.7 at 0 eV and increases with pressure. Chlorine has a low refractive index, whereas iodine demonstrates the greatest. The highest fluctuation is shown for Br. The dielectric characteristics vary from around 5 to 7.5 F/m. Chlorine (Cl) has the least charge storage capacity, while iodine (I) demonstrates the most, of which both increase with pressure in all compounds. Structure FrGeX3 (X = Cl, Br, I) is hardened and made more ductile by applying hydrostatic pressure, as seen by the increasing bulk, Young’s, and shear modulus values, as well as the elastic constants (C11 and C12). While the electrons were in a co-linear position, the magnetic property was also studied by optimizing the band structure and density of states. The diamagnetic property of the combination FrGeX3 (where X = Cl, Br, I) remained unchanged even when subjected to increased pressure. According to the findings, this perovskite material has remarkable absorption properties, which point to a change in its behavior from semiconductor to metal. Their potential uses in solar cells, UV absorbers, and optoelectronic devices are highlighted by these computational results.

Polycrystalline Lead-Free Perovskite Direct X-Ray Detectors with High Durability and Low Limit of Detection via Low-Temperature Coating.

Direct X-ray detectors represent a transformative technology in the realm of radiography and imaging. The double halide-based perovskite cesium silver bismuth bromide (Cs2AgBiBr6) has emerged as a promising material for use in direct X-ray imaging, owing to its nontoxic composition, strong X-ray absorption, decent charge mobility lifetime product (μτ), and low-cost preparation. However, formidable issues related to scalability and ion migration, stemming from intrinsic factors such as halogen vacancies and grain boundaries, have presented significant impediments. These issues have been associated with substantial noise, baseline instability, and a curtailment of detection performance. In response to these multifaceted challenges, we propose a slurry-based in situ treatment technique for fabricating robust Cs2AgBiBr6 thick films. This novel approach adeptly mitigates halogen vacancies, actively passivates grain boundaries, and concurrently elevates the ion migration activation energy, thus effectively suppressing ion migration. Consequently, the obtained X-ray detector exhibits excellent operating stability with minimal signal drift of 8.5 × 10-9 nA cm-1 s-1 V-1 and achieves a remarkable 385% increase in sensitivity with a limit of detection as low as 7.8 nGyair s-1. These results mark a significant step toward the development of high-performance and long-lasting lead-free perovskite direct X-ray detectors.

Crystallization control of wide-bandgap perovskites for efficient solar cells via adding an anti-solvent into the perovskite precursor.

Organic-inorganic halide-based wide-bandgap perovskite solar cells (PSCs) have been researched extensively due to their potential application in tandem solar cells. In this study, we directly added an anti-solvent (diethyl ether, DE) into the perovskite precursor for controlling the crystallization process of perovskite layers with a wide bandgap (1.74 eV). The introduction of DE could facilitate the nucleation and accelerate the perovskite growth during the spin-coating process. Due to the improved crystallization of the perovskite, the wide-bandgap PSCs showed a high power-conversion efficiency (PCE) of 19.7% on average with improved current density and fill factor. In contrast, the control devices without using DE exhibited a low average PCE of 17.6%. Moreover, the ambient stability of the related PSCs was simultaneously enhanced with a remarkably decreased PCE degradation, from 31.3% to 16.8%, after 16 days of storage and measurement. The DE-assisted well-crystallized PSCs showed a highest PCE of 20.1%, with a stable current output and negligible hysteresis. Our research provides a simple and effective way for controlling the crystallization of wide-bandgap perovskite layers and hence improving the performance of wide-bandgap PSCs.

Molecule-bridged electron-selective contact for high-efficiency halide-based perovskite solar cells

This paper achieves efficient and stable PSCs by constructing molecular bridges between the buried interfaces. PSCs passivated by the H2Mi interface molecular bridge have been proven to have a high PCE of 24.34% and excellent light stability.

Numerical simulation and performance optimization of a lead-free inorganic perovskite solar cell using SCAPS-1D

The perovskite solar cells, founded on lead halides, have garnered significant attention from the photovoltaic industry owing to their superior efficiency, ease of production, lightweight characteristics, and affordability. However, due to the hazardous nature of lead-based compounds, these solar cells are currently unsuitable for commercial production. In this context, a lead-free perovskite, cesium-bismuth iodide (Cs3Bi2I9) is considered as a potential alternative to the lead halide-based cell due to their non-toxicity and stability, but this perovskite cannot be matched with random hole transport layer (HTL) and electron transport layer (ETL) materials compared to lead halide-based perovskite because of their crystal structure and band gap. Therefore, in this study, performance comparison of different ideal HTL and ETL materials for Cs3Bi2I9 perovskite layer were studied using SCAPS-1D device simulation on the basis of open circuit voltage, short circuit current, power conversion efficiency (PCE) and fill factor (FF) as well as several novel PSC configuration models were designed that can direct for further experimental research for PSC device commercialization. Results from this investigation reveals that the maximum efficiency of 20.96 % is obtained for the configuration ITO/WS2/Cs3Bi2I9/NiO/Au with optimized parameters such as thickness 400 nm, band gap 2.1eV, absorber layer defect density 1012 cm−3, donor density of ETL 1018 cm−3 and the acceptor density of HTL 1020 cm−3.

Numerical simulations, design and modeling of methylammonium tin iodide halide-based single-junction perovskite solar cell

Numerical simulations, design and modeling of methylammonium tin iodide halide-based single-junction perovskite solar cell

Physically realistic, parametric model for excitonic critical point parabolic band oscillators

Critical point parabolic band (CPPB) oscillators are often useful to model the optical response of semiconductor materials, such as hybrid organic–inorganic lead halide-based perovskites, to incident photons in the form of the complex dielectric function (ε=ε1+iε2) spectra. Some models of ε using CPPB oscillators are not guaranteed Kramers–Kronig (KK) consistent (and therefore not physically realistic), may have excess or arbitrary parameter values, or may require prohibitively long computational time when used to fit ellipsometric spectra. For excitonic CPPBs, commonly used to describe the optical response of hybrid organic–inorganic lead halide-based perovskite materials, a physically realistic, parametric model of ε is developed from the KK relationship between ε1 and ε2 for a number of CPPB oscillators with an Urbach tail below the lowest direct transition. This parametric model is shown to produce the same line shape reported from previous works accurately and more quickly than other available KK-consistent CPPB models.

Investigation of highly efficient self-powered photo-detector performance of all inorganic lead-free halide perovskites (CsSnCl3) nanocrystals (NCs) decorated Er: ZnO nanowires (NWs)/Si heterojunctions

In this study, a zero-biased or self-powered heterojunction photodetector is fabricated by using the combination of lead-free halide-based inorganic perovskite (CsSnCl3) and erbium (Er)-doped ZnO nanowires (NWs) on Si platform. The main advantages of such types of heterojunctions are cost-effective fabrication procedure, highly stable and responsive photoresponse, and, such devices exhibit low dark current and high photo-to-dark current ratio of >102. The HRTEM images confirm that CsSnCl3 perovskites nanocrystals (NCs) are randomly decorated over the ZnO NWs. The UV–visible spectroscopy shows the absorption edges and bandgaps of perovskites NCs, ZnO NWs, and combined heterojunctions. The structural, chemical compositional, and defect-related optical transitions are studied in detail by employing XRD, XPS, and PL results. The highest zero-biased photo-response at 374 nm is achieved for the 1%Er: ZnO–CsSnCl3 NWs/Si heterojunction and corresponding calculated responsivity and detectivity values are obtained to be 0.196 A/W and 2.48 × 1011 Jones, respectively. Along with it, such selective Er-doped NWs perovskites heterojunction exhibits relatively superior linear dynamic range (LDR) (51.76 dB) and rapid response speed (rise time: fall time = 83 ms:63 ms) as compared to reported values. Hence, current work demonstrates that Er-doped oxide-perovskite heterojunctions can be a promising candidate for developing high-performance UV/Visible photodetector under self-powered mode.

Experimental and Theoretical Investigations of MAPbX3 -Based Perovskites (X=Cl, Br, I) for Photovoltaic Applications.

This work mainly focuses on synthesizing and evaluating the efficiency of methylammonium lead halide-based perovskite (MAPbX3 ; X=Cl, Br, I) solar cells. We used the colloidal Hot-injection method (HIM) to synthesize MAPbX3 (X=Cl, Br, I) perovskites using the specific precursors and organic solvents under ambient conditions. We studied the structural, morphological and optical properties of MAPbX3 perovskites using XRD, FESEM, TEM, UV-Vis, PL and TRPL (time-resolved photoluminescence) characterization techniques. The particle size and morphology of these perovskites vary with respect to the halide variation. The MAPbI3 perovskite possesses a low band gap and low carrier lifetime but delivers the highest PCE among other halide perovskite samples, making it a promising candidate for solar cell technology. To further enrich the investigations, the conversion efficiency of the MAPbX3 perovskites has been evaluated through extensive device simulations. Here, the optical constants, band gap energy and carrier lifetime of MAPbX3 were used for simulating three different perovskite solar cells, namely I, Cl or Br halide-based perovskite solar cells. MAPbI3 , MAPbBr3 and MAPbCl3 absorber layer-based devices showed ~13.7 %, 6.9 % and 5.0 % conversion efficiency. The correlation between the experimental and SCAPS simulation data for HIM-synthesized MAPBX3 -based perovskites has been reported for the first time.

Numerical investigation of lead free Cs2TiBr6 based perovskite solar cell with optimal selection of electron and hole transport layer through SCAPS-1D simulation

Halide-based perovskite has several advantages, including high efficiency, ease of manufacture, and low cost. In general, hazardous lead (Pb) is used in perovskite solar cells as an absorber layer, while polymer, which is unstable in nature used as the electron/hole transport layer. Despite its appealing characteristics, the device uses of lead and degradable components must be addressed. Lead-free titanium-based inorganic perovskite solar cells (PSCs) have drawn strong scientific interest in recent years in order to reduce the possibly detrimental effects of lead on the environment. Titanium is non-toxic, robust, inexpensive, and widely available when compared to other elements. The performance of PSCs is simulated and optimized using the SCAPS-1D software. The effects of various parameters of ZnO and CuSbS2 as charge transport materials on the Cesium Titanium (IV) Bromide (Cs2TiBr6) perovskite solar cell were examined in this study. Results indicate that a highly efficient PSC with a power conversion efficiency (PCE) of 26.96 %, a Voc of 1.0476 V, and an FF of 81.36 % is achieved after numerically optimized the perovskite layer thickness, doping concentration,defect density,and other device input parameters. The observed results are very encouraging and show the potential of Cs2TiBr6 for efficient and environmentally friendly solar applications. The outcomes of this study are likely to not only improve understanding but also motivate further research into the lead-free perovskite solar cell.

Synthesis, structural and optical properties of lead free Cs2CuBiCl6: A potential & promising eco-friendly double perovskite for solar cell applications

Lead-free halide-based double perovskite (DP) compounds have grasped the interest of the research community as a potential alternative to the toxicity-degradability problems associated with lead-halide single perovskites. In this study, we have synthesized a potential & promising nontoxic halide DP Cs2CuBiCl6 for the very first time by adopting a new chemical synthesis route. Herein, we have examined the optical, surface, and structural characteristics of synthesized DP. X-ray diffraction (XRD) has been done to inspect its structural behavior and the obtained peaks are in good agreement with reference data. Moreover, the morphology of synthesized material has been confirmed by scanning electron microscopy (SEM). Further, the optical study done by measuring photoluminescence (PL) spectra provides a broad peak at 500 nm due to intraband transition. The electronic property of DP Cs2CuBiCl6 has been studied by calculating the direct bandgap of 1.57 eV. The synthesized DP material is a small bandgap material in comparison with the bulky materials and its property is similar to the lead perovskites. In additionally, we built a photovoltaic effect based solar cell device, and we have measured the illuminated and dark I–V characteristics, and estimated the power conversion efficiency of the fabricated device. The acquired power conversion efficiency (PCE) of solar cells device is 1.87%, which is comparable with the previous studies of double perovskites and it can be lead halide single perovskite counterpart. This investigation opens a new and realistic approach for the synthesis and study of lead-free DP for remarkable photovoltaic applications in green technology domain.

Metal oxide nanoparticles as an electron-transport layer in perovskite solar cell

The research on the application of lead-free perovskite materials as an active layer in solar cells has been positively carried out for the last few years. Although the efficiency of lead-contained metal halide-based Perovskite has reached above 25%, but lead is a highly toxic substance that is hazardous to the environment, and this is one of the obstacles to their commercialization. In this article, a Sn-based Perovskite (CH3NH3SnI3) solar cell with two distinct electron transport layers was simulated using GPVDM (General Purpose Photovoltaic Device Model) and fabricated with a simple sol-gel method. Along with the absorber layer, the charge transport materials also play an essential role in extracting electrical power. The comparison of ZnO and TiO2 as electron collectors has been investigated and characterized, the hole-carrying layer has been eliminated for better findings. Remarkably, we achieve an efficiency of 7.33% and 6.75% in simulation and 6.90% and 5.81% from fabricated devices using ZnO and TiO2, respectively.

Performance of Cs-Doped Carbon-Based Perovskite Solar Cells in Ambient Environment

The development of organometal halide-based perovskite solar cells (PSCs) has made remarkable progress in photovoltaics. The commercialization of PSCs is still significantly limited, owing to their poor stability and the high material cost of a hole transport layer (HTL) and metal electrodes. To counter these issues, a carbon-based HTL and noble metal-free PSCs are being used. In this work, the effect of Cs-doping on perovskite film morphology and device performance has been systematically studied because the Cs+ and Br− ions-doping has proved to be a good choice to improve the stability of PSCs in combination with a carbon electrode. The results showed that when the Cs-doping concentration in perovskite film, MA1−xCsxPb(I1−yBry)3, was equal to x = 0.09, there was a substantial change in the morphological and optoelectronic properties of perovskite films. The grain size of perovskite films was improved from 70 nm (x = 0.00 control) to 170 nm (x = 0.09 Cs-doped), reducing grain boundaries. Moreover, the trap states were additionally passivated resulting in improved radiative recombinations in the perovskite film. The device fabrication was carried out in a controlled dry glovebox, with relative humidity < 40% using carbon as a counter electrode. As a result, Cs-doped PSCs showed a significant increase in efficiency (5.27%) compared to control PSCs (1.55%).

A 0D lead-free Nickel halide-based perovskite exhibiting greenish light emission and high color rendering index

In this paper, a novel low-dimensional Ni(II)-based hybrid perovskite compound [(C3H7)4N]Ni2Cl6 endowed with interesting solid-state light-emission properties has been investigated using thermal (TGA-DSC), Hirshfeld surfaces, FT-Infrared spectroscopy, optical and photoluminescence measurements. The structure packing consists of 0D framework ascribed as a layered arrangement of organic and dimeric [Ni2Cl6]1− groups perpendicular to the crystallographic c axis and stabilized by means of weak intermolecular bonds yielding a 3D framework. The UV-visible investigation reveals a direct optical gap energy of value 3.72 eV, confirming the semi-conducting nature of the elaborated material. The photoluminescence properties reveals a greenish broad-band emission caused by self-trapped excitonic states (STESs) as well as the remarquable the inorganic tetrahedron distortion in the 0D crystal dimensionality. Such bright light emission yields to good luminescence properties with a very high CRI value of 96, CIE color coordinates of (0.32; 0.35), and a CCT value of 5722 K and. The Stokes shift between excitation wavelengths (325, 345, 375, 395 nm) and their corresponding emission bands (450, 460, 472, 480 nm) are discussed. The current findings could be used for the development of environment-friendly hybrid perovskites for UV and solar cell applications.

Recent Progress of Film Fabrication Process for Carbon-Based All-Inorganic Perovskite Solar Cells

Although the certified power conversion efficiency of organic-inorganic perovskite solar cells (PSCs) has reached 25.7%, their thermal and long-term stability is a major challenge due to volatile organic components. This problem has been a major obstacle to their large-scale commercialization. In the last few years, carbon-based all-inorganic perovskite solar cells (C−IPSCs) have exhibited high stability and low-cost advantages by adopting the all-inorganic component with cesium lead halide (CsPbI3−xBrx, x = 0 ~ 3) and eliminating the hole-transporting layer by using cheap carbon paste as the back electrode. So far, many astonishing developments have been achieved in the field of C−IPSCs. In particular, the unencapsulated CsPbBr3 C-IPSCs exhibit excellent stability over thousands of hours in an ambient environment. In addition, the power conversion efficiencies of CsPbI3 and CsPbI2Br C-IPSCs have exceeded 15%, which is close to that of commercial multicrystalline solar cells. Obtaining high-quality cesium lead halide-based perovskite films is the most important aspect in the preparation of high-performance C-IPSCs. In this review, the main challenges in the high-quality film fabrication process for high performance C-IPSCs are summarized and the film fabrication process strategies for CsPbBr3, CsPbIBr2, CsPbI2Br, and CsPbI3 are systematically discussed, respectively. In addition, the prospects for future film fabrication processes for C-IPSCs are proposed.

Numerical Simulation and Optimization of Inorganic Lead-Free Cs3Bi2I9-Based Perovskite Photovoltaic Cell: Impact of Various Design Parameters

The lead halide-based perovskite solar cells have attracted much attention in the photovoltaic industry due to their high efficiency, easy manufacturing, lightweight, and low cost. However, these lead halide-based perovskite solar cells are not manufactured commercially due to lead-based toxicity. To investigate lead-free inorganic perovskite solar cells (PSCs), we investigated a novel Cs3Bi2I9-based perovskite configuration in SCAPS-1D software using different hole transport layers (HTLs). At the same time, WS2 is applied as an electron transport layer (ETL). Comparative analysis of the various design configurations reveals that ITO/WS2/Cs3Bi2I9/PEDOT:PSS/Au offers the best performance with 20.12% of power conversion efficiency (PCE). After optimizing the thickness, bandgap, defect density, and carrier density, the efficiency of the configuration is increased from 20.12 to 24.91%. Improvement in other performance parameters such as short circuit current (17.325 mA/cm2), open circuit voltage (1.5683 V), and fill factor (91.66%) are also observed after tuning different attributes. This investigation indicates the potential application of Cs3Bi2I9 as a lead-free and stable perovskite material that can contribute to improving the renewable energy sector.