Inorganic Solar Cells Research Articles

Reducing Non-Radiative Energy Losses in Non-fullerene Organic Solar Cells.

With the rapid advancement of non-fullerene acceptors (NFAs), the power conversion efficiency (PCE) of organic solar cells (OSCs) has surpassed the 20% threshold, highlighting their considerable potential as next-generation energy conversion devices. In comparison to inorganic or perovskite solar cells, the open-circuit voltage (Voc) of OSCs is constrained by substantial non-radiative energy losses (ΔEnr), leading to values notably below those anticipated by the Shockley-Queisser limit. In OSCs, non-radiative energy losses are intimately associated with the electroluminescent quantum efficiency (EQEEL) of charge transfer states, which is in turn directly affected by the photoluminescence quantum yield (PLQY) of acceptor materials. Consequently, enhancing the PLQY of low-bandgap acceptor materials has emerged as a pivotal strategy to effectively mitigate ΔEnr. This review article delves into the intrinsic correlation between molecular structure and PLQY from the vantage point of acceptor material design. It further explores methodologies for designing acceptor materials exhibiting high PLQY, with the ultimate goal of realizing OSCs that combine high efficiency with minimal ΔEnr.

Defection-stripping and balanced carrier extraction strategy enables efficient and ultra-low hysteresis of inverted inorganic perovskite solar cells

Defection-stripping and balanced carrier extraction strategy enables efficient and ultra-low hysteresis of inverted inorganic perovskite solar cells

Ionic Liquid-Assisted Strategy for Morphology Engineering of Inorganic Cesium-Based Perovskite Thin Films Toward High-Performance Solar Cells.

The wide bandgap CsPbI2Br perovskite materials have attracted significant attention due to their high thermal stability and compatibility with narrow bandgap materials in tandem devices. The performance of perovskite solar cells (PSCs) is highly dependent on the quality of the perovskite layer, which is governed by the crystallization process during solution processing. However, the crystallization dynamics of CsPbI2Br thin films remain less explored compared to conventional organic-inorganic perovskites. Achieving high-quality CsPbI2Br films with uniform morphology and large perovskite grains remains challenging with standard solution techniques. This study applies the ionic liquid (IL) [EMIM]+[PF6]- as an additive within the bulk CsPbI2Br absorber layer. Within our experimental regime, [EMIM]+[PF6]- accelerates the crystallization process while promoting the formation of large perovskite grains, a feature not commonly observed in previous studies. Our experimental results suggest that the IL acts as heterogeneous nucleation sites, and varying IL incorporation amount significantly impacts the morphology of CsPbI2Br perovskite films. Consistent UV-vis and photoluminescence (PL) red-shifts are observed in the IL-incorporated CsPbI2Br films, with X-ray diffraction (XRD) data projecting an influence on the perovskite crystal structure. These findings provide new insights into the role of ILs in controlling crystallization and morphology that have been minimally discussed in the literature. The incorporation of an optimized amount of [EMIM]+[PF6]- promotes the formation of highly crystalline perovskite thin films with excellent morphology, reducing defect density, enhancing carrier transport, and yielding large grain sizes. As a result, PSCs fabricated with [EMIM]+[PF6]- achieved a power conversion efficiency (PCE) of 17.11% (stabilized at 15.87%) and an open-circuit voltage (VOC) of 1.39 V, along with improved stability compared to control devices. This work provides a straightforward approach for producing high-quality CsPbI2Br thin films with high reproducibility, contributing valuable advancements to Cs-based PSCs.

Design and performance exploration of Pb-free low-cost all-inorganic perovskite-inspired CuAgBi2I8 solar cells: theoretical approach

Abstract Organic–inorganic halide perovskites have demonstrated great potential for photovoltaic applications owing to their unprecedented optoelectronic properties and low manufacturing costs. However, the commercialization of this technology is hindered by its thermal instability and inherent toxicity. In this study, SCAPS-1D simulation software was used to study the performance of solar cell based on CuAgBi2I8, which is a novel inorganic non-toxic lead-free perovskite-inspired material. Different electron transport layers (TiO2, In2S3, ZnO, Zn0.75Mg0.25O,SnO2 and SrTiO3) and hole transport layers (CuI, PEDOT:PSS, CuSCN and Cu2O) were studied, our research indicated that SnO2 and NiO formed the optimal combination. Further analysis revealed that the optimal absorption layer thickness was 900 nm, the absorption layer doping concentration should be less than 1 × 1013 cm−3 and the defect density should be less than 1 × 1014 cm−3. The optimal thickness of SnO2 and NiO was 30 nm, the optimal doping concentration of SnO2 and NiO was 1 × 1020 cm−3, the defect density of absorber layer/SnO2 and absorber layer/NiO interfaces should be less than 1 × 1012 cm−3, C was the optimal back electrode material. Consequently, the optimal device configuration was identified as FTO/SnO2/CuAgBi2I8/NiO/C, the efficiency was improved from original 2.76% to 19.10% after above optimization. These results indicate that solar cell with CuAgBi2I8 as the absorber layer is a potential alternative to organic–inorganic lead halide perovskite solar cells.

Surface Reaction Induced Compressive Strain for Stable Inorganic Perovskite Solar Cells

AbstractCesium‐based inorganic perovskites have emerged as promising light‐harvesting materials for perovskite solar cells (PSCs) due to their promising thermal‐ and photo‐stability. However, obstacles to commercialization remain regarding their phase instability. In this work, we report a facile and effective strategy to regulate the surface compressive strain via in situ surface reaction to stabilize CsPbI3 perovskite. The use of a chelating ligand with a molecular configuration closely matching the integer multiples of the unit cell lattice parameters of CsPbI3 induces compressive strain at the surface of CsPbI3. The chemical bonding and strain modulation synergistically not only passivate film defects, but also inhibit perovskite phase degradation, thus significantly improving the intrinsic stability of inorganic perovskite. Consequently, enhanced power conversion efficiency (PCE) of 21.0 % and 18.6 % were respectively achieved in 0.16‐cm2 lab‐scale devices and 25.3‐cm2 solar modules. Further, surface reaction enables PSCs with enhanced thermal and operational stability; these devices retain over 95 % of their initial PCE after damp‐heat tests (i.e., in 85 °C and 85 % R. H. air) for 2000 h, and remain 99 % of their initial PCE after operating for 2000 h, representing one of the most stable inorganic PSCs reported so far.

Customizing Aniline-Derived Molecular Structures to Attain beyond 22 % Efficient Inorganic Perovskite Solar Cells.

The characteristics of the soft component and the ionic-electronic nature in all-inorganic CsPbI3-xBrx perovskite typically lead to a significant number of halide vacancy defects and ions migration, resulting in a reduction in both photovoltaic efficiency and stability. Herein, we present a tailored approach in which both anion-fixation and undercoordinated-Pb passivation are achieved in situ during crystallization by employing a molecule derived from aniline, specifically 2-methoxy-5-trifluoromethylaniline (MFA), to address the above challenges. The incorporation of MFA into the perovskite film results in a pronounced inhibition of ion migration, a significant reduction in trap density, an enhancement in grain size, an extension of charge carrier lifetime, and a more favorable alignment of energy levels. These advantageous characteristics contribute to achieving a champion power conversion efficiency (PCE) of 22.14 % for the MFA-based CsPbI3-xBrx perovskite solar cells (PSCs), representing the highest efficiency reported thus far for this type of inorganic metal halide perovskite solar cells, to the best of our knowledge. Moreover, the resultant PSCs exhibits higher environmental stability and photostability. This strategy is anticipated to offer significant advantages for large-area fabrication, particularly in terms of simplicity.

A Scorpion−type Dopant‐Free Hole Transport Material for n‐i‐p Organic−Inorganic Hybrid Perovskite Solar Cells

It is significant to develop dopant‐free hole transport materials (HTMs) to improve the long‐term stability of n‐i‐p organic−inorganic hybrid perovskite solar cells (PSCs). In this work, two HTMs (DTTP‐T and DTTP‐D) based on dithienothiopyrrole (DTTP) core were synthesized to explore the effects of different substituents on the nitrogen atom on the properties of HTMs. Compared with anisole‐substituted DTTP‐D, triarylamine‐substituted scorpion‐type DTTP‐T shows better matching energy level, stronger charge transfer and defect passivation ability. Therefore, the power conversion efficiency (PCE) of dopant‐free DTTP‐T‐based n‐i‐p PSCs reaches 18.67%, which is comparable to that of doped Spiro‐OMeTAD (19.51%). More encouragingly, the efficiency of DTTP‐T‐based devices remains above 80% of its initial efficiency after 1728 h of storage in air, while the Spiro‐OMeTAD‐based devices could only maintain 600 h. This work provides a good reference for the development of dopant‐free small molecular HTMs for efficient and stable PSCs.

Atomistic insight into the device engineering of inorganic halide perovskite solar cells

Perovskites provide a promising pathway for fabricating efficient and lightweight solar cells, which could be game-changers in the renewable energy landscape. Yet, the phase stability and device design are still the key issues of perovskite-based photovoltaics. Herein, we evaluated the phase stability of CsPbX3 (X = I, Br, and Cl) upon analyzing the lattice dynamics from first-principles and then predicted fundamental properties including bandgap, carrier mobility, and optical absorption as input to optimize the device design of solar cell. A maximum power conversion efficiency (PCE) of 12.36 % was achieved for a CsPbBr3-based solar cell. Those findings highlight the potential of CsPbX3 perovskites for high-efficiency solar cells. The computational approach provides a comprehensive understanding of the material's structural stability, charge-carrier dynamics, and optoelectronic characteristics. The collective analysis enables a holistic understanding of CsPbX3 perovskites and provides a roadmap for future advancements in perovskite solar-cell technology.

Probing the Impact of Four BSF Layers on MASnI3‐Based Lead‐Free Perovskite Solar Cells for >33% Efficiency

AbstractThis study systematically investigates the impact of various layers of the back surface field (BSF) on the performance of CH₃NH₃SnI₃ (MASnI₃)‐based lead‐free mixed organic–inorganic halide perovskite solar cells. By employing SCAPS‐1D (Solar Cell Capacitance Simulator in One Dimension) simulation software, the behavior of solar cells is analyzed incorporating BSF layers of CuI, NiO, ZnTe, and CBTS. The findings indicate that the inclusion of these BSF materials significantly enhances power conversion efficiency (PCE), with CBTS showing the highest PCE of 33.57%. The energy band diagrams reveal that the BSF layers effectively reduce recombination losses at the rear interface and improve charge carrier collection. Detailed analysis of photovoltaic parameters, such as open‐circuit voltage (Voc), short‐circuit current density (Jsc), fill factor (FF), and overall PCE, underscores the superiority of CBTS as optimal BSF materials. Temperature variation studies demonstrate that CBTS maintains superior performance across a range of temperatures, highlighting its potential for high‐efficiency, thermally stable perovskite solar cells. This comprehensive investigation provides valuable insights for optimizing the design and performance of MASnI₃‐based perovskite solar cells, with the aim of efficiencies greater than 33%.

Self-Assembled Monolayer Suppresses Interfacial Reaction between NiOx and Perovskite for Efficient and Stable Inverted Inorganic Perovskite Solar Cells.

Inorganic NiOx has attracted tremendous attention in organic-inorganic hybrid perovskite solar cells (PSCs) in recent years but is relatively less used in all-inorganic PSCs. In this study, we have discovered and confirmed the detrimental interfacial reaction between NiOx and DMAI-containing CsPbI3 inorganic perovskites. Thus, a self-assembled monolayer, Br-2PACz, is employed to modify the NiOx surface to obstruct the adverse interfacial reaction and further improve the device performance. The results demonstrate that Br-2PACz modification on NiOx can also improve interface contact, perovskite film morphology, and energy level alignments. Consequently, a champion power conversion efficiency (PCE) of 19.34% with a high open-circuit voltage (VOC) of 1.15 V is obtained for inverted NiOx/Br-2PACz-based CsPbI3 PSCs compared to the reference NiOx-based PSC with a moderate PCE of 15.16% (VOC 1.05 V). Moreover, the stabilities of both CsPbI3 films and devices exhibited significant enhancement after Br-2PACz modification. The unpacked PSCs could maintain 80, 73, and 89% of the initial efficiency after aging in 30-35% RH for 960 h, heating at 60 °C for 48 h, and continuous illumination for 284 h, respectively, highly superior to the reference devices. Our work offers a facile and effective approach for developing high-performance inverted NiOx-based CsPbI3 PSCs.

Customizing Aniline‐Derived Molecular Structures to Attain beyond 22 % Efficient Inorganic Perovskite Solar Cells

AbstractThe characteristics of the soft component and the ionic‐electronic nature in all‐inorganic CsPbI3‐xBrx perovskite typically lead to a significant number of halide vacancy defects and ions migration, resulting in a reduction in both photovoltaic efficiency and stability. Herein, we present a tailored approach in which both anion‐fixation and undercoordinated‐Pb passivation are achieved in situ during crystallization by employing a molecule derived from aniline, specifically 2‐methoxy‐5‐trifluoromethylaniline (MFA), to address the above challenges. The incorporation of MFA into the perovskite film results in a pronounced inhibition of ion migration, a significant reduction in trap density, an enhancement in grain size, an extension of charge carrier lifetime, and a more favorable alignment of energy levels. These advantageous characteristics contribute to achieving a champion power conversion efficiency (PCE) of 22.14 % for the MFA‐based CsPbI3‐xBrx perovskite solar cells (PSCs), representing the highest efficiency reported thus far for this type of inorganic metal halide perovskite solar cells, to the best of our knowledge. Moreover, the resultant PSCs exhibits higher environmental stability and photostability. This strategy is anticipated to offer significant advantages for large‐area fabrication, particularly in terms of simplicity.

To Maximize Luminescence for an Efficient Organic Solar Cell†

Comprehensive SummaryWith the continuous development of photovoltaic materials, organic solar cells (OSCs) have made remarkable advancements, surpassing a power conversion efficiency (PCE) of 20%. However, the PCEs of OSCs remain lower than that of inorganic solar cells due to significant energy losses, mainly stemming from the relatively large non‐radiative recombination losses (usually be expressed as ∆E3), resulting in low open‐circuit voltages. This can be achieved by reducing non‐radiative recombination, and hereby increasing the electroluminescence quantum efficiency (EQEEL) of the photo‐active layer. This review analyzes the significance of luminescence efficiency in achieving high‐performance OSCs by examining the reciprocal relationship between ∆E3 and EQEEL. High‐efficiency organic solar cells can also be used as effective organic light‐emitting diodes (OLEDs). The discussion provides insights into the influencing factors of EQEEL and the mechanisms for adjusting various parameters, which include enhancements in photoluminescence quantum yield and the proportion of radiative excitons. The objective is to offer insights into the crucial role of luminescence performance in OSC development, guiding researchers toward developing novel photovoltaic materials or optimization strategies to enhance the luminescence performance of the active layer in OSCs, fostering the simultaneous advancement of OSCs and OLEDs. Key Scientists

Columnar Macrocyclic Molecule Tailored Grain Cage to Stabilize Inorganic Perovskite Solar Cells with Suppressed Halide Segregation

AbstractSolidifying the soft lattice of all‐inorganic mixed‐halide perovskites is of great importance to restrain the notorious halide segregation under persistent light illumination. Herein, a multifunctional columnar macrocyclic molecule additive, namely cucurbituril into perovskite precursor to enhance the crystallization and reduce the defect density in the final perovskite film is introduced. Based on the theoretical calculation and simulation, the cucurbituril molecule with a strong double‐ended negatively‐charged cavity surrounded by terminated oxygen atoms not only coordinates with dangling Pb2+ ions to form host‐guest complexation but also induces an electric dipole field at perovskite grain boundary to effectively repel the iodide ion migration from the inside grain to the defective boundary, significantly suppressing the halide segregation and improving the device performance. As a result, the carbon‐based, all‐inorganic CsPbI2Br solar cell achieves an enhanced efficiency of 15.59% with great tolerance to environmental stresses. These findings provide new insights into the development of a novel passivation strategy with macrocyclic molecules for making high‐efficiency and stable perovskite solar cells.

Surface Reaction Induced Compressive Strain for Stable Inorganic Perovskite Solar Cells.

Cesium-based inorganic perovskites have emerged as promising light-harvesting materials for perovskite solar cells (PSCs) due to their promising thermal- and photo-stability. However, obstacles to commercialization remain regarding their phase instability. In this work, we report a facile and effective strategy to regulate the surface compressive strain via in-situ surface reaction to stabilize CsPbI3 perovskite. The use of a chelating ligand with a molecular configuration closely matching the integer multiples of the unit cell lattice parameters of CsPbI3 induces compressive strain at the surface of CsPbI3. The chemical bonding and strain modulation synergistically not only passivate film defects, but also inhibit perovskite phase degradation, thus significantly improving the intrinsic stability of inorganic perovskite. Consequently, enhanced power conversion efficiency (PCE) of 21.0% and 18.6% were respectively achieved in 0.16-cm2 lab-scale devices and 25.3-cm2 solar modules. Further, surface reaction enables PSCs with enhanced thermal and operational stability; these devices retain over 95% of their initial PCE after damp-heat tests (i.e., in 85 ℃ and 85% R.H. air) for 2000 h, and remain 99% of their initial PCE after operating for 2000 h, representing one of the most stable inorganic PSCs reported so far.

Surface sulfidation constructing gradient heterojunctions for high‐efficiency (approaching 18%) HTL‐free carbon‐based inorganic perovskite solar cells

Surface sulfidation constructing gradient heterojunctions for high‐efficiency (approaching 18%) HTL‐free carbon‐based inorganic perovskite solar cells

Quantifying the multifaceted influence of HTLs on the photovoltaic performance of inorganic Cs2TiBr6 solar cells: an OghmaNano numerical investigation

In this study, an environmentally friendly, stable Cs2TiBr6 perovskite solar cell (PSC) with two device configurations FTO/TiO2/Cs2TiBr6/Cu2O/Au and FTO/TiO2/Cs2TiBr6/MoO3/Au have been simulated using OghmaNano software. Two-hole transport layers (HTLs) have been used to do a comparative study. Cuprous Oxide (Cu2O) and Molybdenum Oxide (MoO3) are inorganic HTLs with bandgaps of 2.17 eV and 3 eV, respectively that are plentiful, non-toxic, and ideal for band matching. The study aims to optimize the PSCs performance by using inorganic MoO3 and Cu2O as HTL to replace the traditionally organic HTL. Key parameters like thickness, electron mobility, and recombination rate constant have been optimized to yield maximum efficiency. The outcomes show that Cu2O-HTL demonstrated superior performance with an optimal structure, resulting in a high efficiency of 21% and an improved fill factor (FF) of up to 86.52%. These findings suggest that Cs2TiBr6-based PSCs could significantly impact future photovoltaic research.

Efficiency enhancement and optimization of lead-free Cs2PtI6 perovskite solar cell

Perovskite solar cells (PSCs) are famous for their potential to produce efficient, flexible, and low-cost solar energy. This study explores the possibility of eco-friendly, lead-free, inorganic solar cells using Cs2PtI6 as the light-absorbing layer and NiO as the hole transport layer (HTL). It carefully optimizes various factors, including the thickness, doping concentration, defect density, and the effects of radiative recombination of the absorber layer, along with different hole and electron transport layers. The study also examines interfacial defects and resistances within the device. The density of defects at the interface between the HTL and the absorber layer is a crucial factor influencing the device’s performance. Additionally, the study evaluates different metal back contacts, changes in temperature, light intensity, and the spectrum of light. The optimized structure (FTO/ZnO/Cs2PtI6/NiO/Au) achieves an open circuit voltage (VOC) of 1.34 V, a short-circuit current (JSC) of 32.34 mAcm−2, a fill factor (FF) of 75.70%, and an excellent power conversion efficiency (PCE) of 32.70%, showing great promise in solar cell technology.

Inorganic-Derived 0D Perovskite Induced Surface Lattice Arrangement for Efficient and Stable All-Inorganic Perovskite Solar Cells.

The inverted inorganic CsPbI3 perovskite solar cells (PSCs) are prospective candidates for next-generation photovoltaics owing to inherent robust thermal/photo-stability and compatibility for tandems. However, the performance and stability of the inverted CsPbI3 PSCs fall behind the n-i-p counterparts due to poor energetic alignment and abundant interfacial defect states. Here, an inorganic 0D Cs4PbBr6 with a good lattice strain arrangement is implemented as the surface anchoring capping layer on CsPbI3. The Cs4PbBr6 perovskite induces enhanced electron-selective junction and thus facilitates efficient charge extraction and effectively inhibits non-radiative recombination. Consequently, the CsPbI3 PSCs with Cs4PbBr6 demonstrate the highest power conversion efficiency (PCE) of CsPbI3-based inverted PSCs, reaching 21.03% PCE from a unit cell and 17.39% PCE from a module with a 64 cm2 aperture area. Furthermore, the resulting devices retain 92.48% after 1000h under simultaneous 1-sun and damp heat (85°C / 85% relative humidity) environment.

Numerical simulation of all inorganic CsPbIBr2 perovskite solar cells with diverse charge transport layers using DFT and SCAPS-1D frameworks

All inorganic CsPbX3 perovskites (X = Br and I) are excellent candidates for stable and efficient perovskite solar cells (PSCs). Among them, CsPbIBr2 demonstrated the most balanced characteristics in terms of band gap and stability. Nevertheless, the power conversion efficiency (PCE) of CsPbIBr2-based solar cells is still far from that of Hybrid PSCs, and more research is required in this aspect. Herein, DFT and SCAPS-1D frameworks are employed to explore the optimized device configurations of CsPbIBr2 PSCs. DFT is used to explore the structural and optoelectronic characteristics of CsPbIBr2, while SCAPS-1D is employed to examine various device structures of CsPbIBr2-based PSCs. The band structure demonstrated the direct band gap nature of CsPbIBr2 with a band gap of 2.12 eV. Moreover, we have used TiO2, SnO2, ZnO, WS2, IGZO, CeO2, In2S3, and CdS as ETLs, and Cu2O, CuI, MoO3, NiO, CuSCN, CuSbS2, CBTS, CFTS, and CuO as HTLs for identifying the best ETL/CsPbIBr2/HTL configurations. Among 72 device combinations, eight sets of PSCs are identified as the most efficient configurations. In addition, the influence of various parameters like the thickness of various layers, doping concentration, perovskite defect density, ETLs and interfaces, series resistances, shunt resistances, and temperature on device performance have been comprehensively studied. The results demonstrate Cu2O as the best HTL for CsPbIBr2 with each ETL, and PSC with device structure ITO/WS2/CsPbIBr2/Cu2O/C exhibited the highest PCE of 16.53%. This comprehensive investigation will provide new path for the development of highly efficient all-inorganic CsPbIBr2 solar cells.

Inorganic salts released from polypyrrole nanocapsules on compact TiO2 layer for highly efficient inorganic CsPbI3-type perovskite solar cells

The compact TiO2 serves as a crucial electron transport layer (ETL) for fabricating high-efficiency CsPbI3 solar cells. Modifying TiO2 with inorganic ions is regarded as a simple and effective method to optimize the band energy level, eliminate interface defects, and enhance the crystallinity of the CsPbI3 film. However, inorganic ions risk being washed away by perovskite solvents such as DMF and DMSO. In this work, core–shell inorganic salt (LiCl, NaCl, ZnCl2)@polypyrrole nanocapsules (PPy NCPs) were fabricated as a buffer layer at the interface of TiO2/CsPbI3 layer. The inorganic salts are released from PPy NCPs during the annealing process of the CsPbI3 precursor film, thereby preventing them from being washed away by the DMF/DMSO solvents. Compared to NaCl@PPy NCPs-TiO2, ZnCl2@PPy NCPs-TiO2, and pristine TiO2 films, the LiCl@PPy NCPs-TiO2 exhibited the best electron conductivity and highest Fermi level. The released LiCl not only passivates point defects in TiO2 by forming Li-O-Ti bonds, optimizing the energy level at the TiO2/perovskite interface, but also incorporates into the CsPbI3 lattice, improving its crystallinity. As a result, solar cells based on LiCl@PPy NCPs-TiO2 layer demonstrated a higher PCE of 19.78 %, along with increased open-circuit voltage (VOC) and fill factor (FF) values of 1.161 V and 83.1 %, respectively. Furthermore, the LiCl@PPy NCPs-TiO2 layer also enhanced the stability of CsPbI3 solar cells under humidity conditions.