Performance Of Perovskite Solar Cells Research Articles

MXene-Embedded PEDOT:PSS Hole-Transport Material for Lead-Free Perovskite Solar Cells.

Improving the energy alignment between charge-transport layers and the perovskite is crucial for further enhancing the photovoltaic performance of tin-based perovskite solar cells (PSCs). Herein, the role of Ti3C2T x MXene in a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer (HTL) on the photovoltaic properties of PSCs is investigated as a function of its concentration. An improved perovskite film formation with reduced pinhole density and a more uniform contact potential difference is noted when MXene is embedded in the PEDOT:PSS HTL. The work function of the HTL is increased according to photoelectronic measurements, leading to a favorable energy alignment with the HOMO of PEA0.2FA0.8SnI3 perovskite. PSCs fabricated using a MXene-embedded PEDOT:PSS HTL delivered a power conversion efficiency (PCE) of 8.35% compared to 7.35% from the pristine counterpart, while retaining ∼90% of its initial PCE after 450 h of storage in a N2 atmosphere.

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.

Making a benign buried bottom interface for high-performance perovskite photovoltaics with a chelating molecule

Interfacial modifications can significantly enhance the photovoltaic performance of perovskite solar cells (PSCs). We introduced an auxiliary chelating agent, 5,6-isopropyridine-L-ascorbic acid (ILAA), to modify the SnO2/perovskite buried interface. By a non-destructive peeling process using a UV epoxy glue, we exposed the buried bottom of the perovskite layer for direct examination. ILAA not only suppressed SnO2 defects and hydroxyl oxygen but also prevented deterioration of the buried bottom of the perovskite layer. Theoretical calculations also confirmed the greater competitiveness of ILAA in interacting with perovskite molecules than dimethyl sulfoxide. The introduction of ILAA optimized the energy band structure of the SnO2-perovskite interface, therefore enhanced the built-in electric field and facilitated efficient charge transfer. Consequently, ILAA-modified PSCs achieved power conversion efficiencies of 24.04 % and 19.10 % for microdevices (0.09 cm2) and modules (19.32 cm2), respectively. These unencapsulated devices exhibited excellent humidity and thermal stability, maintaining over 80 % of their initial performances after being aged in air for 1000 h or continuously heated for 500 h.

High performance and stability of perovskite solar cells achieved through anti-solvent modulation of multi-orientation PbI2 and stress relief

The morphology of the pre-deposited PbI2 layer plays a crucial role in determining the quality of perovskite films in sequentially deposited perovskite solar cells. The main reason is that the PbI2 film is too dense, which makes it difficult for organic salts to fully enter and react with them. This work presents a novel solvent extraction post-treatment method for the construction of bilayer PbI2 films. The PCE of the prepared champion device reaches 23.8 %, which is higher than 21.6 % of the control device. We observed that the perovskite solar cells treated with EA retained over 90 % of their initial efficiency after being stored for approximately 700 h in a nitrogen atmosphere, and over 80 % in air, demonstrating superior stability compared to the control group.

Stabilization of highly efficient perovskite solar cells with a tailored supramolecular interface

The presence of defects at the interface between the perovskite film and the carrier transport layer poses significant challenges to the performance and stability of perovskite solar cells (PSCs). Addressing this issue, we introduce a dual host-guest (DHG) complexation strategy to modulate both the bulk and interfacial properties of FAPbI3-rich PSCs. Through NMR spectroscopy, a synergistic effect of the dual treatment is observed. Additionally, electro-optical characterizations demonstrate that the DHG strategy not only passivates defects but also enhances carrier extraction and transport. Remarkably, employing the DHG strategy yields PSCs with power conversion efficiencies (PCE) of 25.89% (certified at 25.53%). Furthermore, these DHG-modified PSCs exhibit enhanced operational stability, retaining over 96.6% of their initial PCE of 25.55% after 1050 hours of continuous operation under one-sun illumination, which was the highest initial value in the recently reported articles. This work establishes a promising pathway for stabilizing high-efficiency perovskite photovoltaics through supramolecular engineering, marking a significant advancement in the field.

Molecule Anchoring Strategy Promotes Vertically Homogeneous Crystallization and Aligned Interfaces for Efficient Pb-Sn Perovskite Solar Cells and Tandem Device.

Narrow-bandgap (NBG) Pb-Sn perovskites are ideal candidates as rear subcell in all-perovskite tandem solar cells. Because Pb-Sn perovskites contain multiple components, the rational regulation of vertical structure and both interfaces of the film is primarily crucial to achieve high-performing NBG perovskite solar cells (PSCs). Herein, a molecule anchoring strategy is developed to in situ construct Cs0.1MA0.3FA0.6Pb0.5Sn0.5I3 perovskite film with vertically aligned crystals and optimized interfaces. Specifically, l-alanine methyl ester is developed as an anchoring additive to induce the vertical crystal growth, while PEA2PbI3SCN film is introduced to promote the homogeneous crystallization at the buried interface via SCN- anchoring with cations. Further ethylenediamine dihalides (EDA(I/Cl)2) post-treatment leads to the gradient energy level alignment on the film surface. Pb-Sn PSCs based on such film show efficient charge transport and extraction, producing a champion power conversion efficiency (PCE) of 22.3% with an impressive fill factor of 82.14%. Notably, combining with semitransparent 1.78 eV wide-bandgap PSCs, the four-terminal all-perovskite tandem device achieves a PCE of 27.1%. This work opens up a new pathway to boost the performance of Pb-Sn PSCs and their tandem devices.

Solar brilliance unleashed: Maximizing performance of novel carbon-based Rb-doped CsSnI3 perovskite solar cells by gradient doping

The commercialization of state-of-the-art perovskite solar cells (PSCs) is hindered by lead toxicity, high production costs, and stability issues. The current study addresses these challenges by exploring lead-free Rb-doped CsSnI3 perovskite with carbon-based materials. Herein, the impact of Rb-doping in CsSnI3 perovskite has been thoroughly investigated on its structural, electrical, and optical properties via DFT studies. The results show that the incorporation of Rb-cation into CsSnI3 significantly enhances the stability of the perovskite active layer (PAL), addressing the major challenge of degradation under environmental conditions. Further, DFT results are used to investigate the potential of Cs0.75Rb0.25SnI3 as a PAL in device architecture FTO/ETL/Cs0.75Rb0.25SnI3/CNTs/C via SCAPS-1D with different electron transport layer (ETL) and carbon-based hole transport layer and back contact. Simulation results show that among different ETLs, WO3 demonstrates the best performance. Further, we have employed a gradient doping (GD) strategy in PAL, dividing it into two sub-layers of thickness 200 nm each with different doping concentrations in the simulated device FTO/WO3/CsRbSnI3/CNTs/C. The aim of implementing GD is to strengthen the electric field and improve the energy band alignments which helps in reducing interfacial recombination. Besides, the impact of band-gap, interfacial defects, hysteresis effect, and C–V and C–F analysis are examined. The results reveal that at doping gradient G = 300, the device attains the best PCE of 19.05% with Eg of 1.32 eV (PAL-1) and 1.22 eV (PAL-2). This study can serve as a benchmark for developing high-performance and low-cost CsRbSnI3-based PSCs utilizing a gradient doping strategy.

Enhancing performance of low-temperature fabricated inverted planar perovskite solar cells through triple-cation perovskite optimization

Perovskite solar cells have garnered significant attention due to the rapidly advancing power conversion efficiency(PCE). Recently, there has been significant interest in enhancing the performance of perovskite solar cells through Cs+ doping. However, the optimal concentration of Cs+ varies between inverted and positive structures, influenced by factors such as cell design, fabrication processes, and performance optimization requirements. In this study, we designed and prepared a novel inverted structure triple cations FA/MA/Cs perovskite solar cell at a low temperature. We observed that the quality of perovskite films can be obviously improved by doping an appropriate amount of Cs+, but excessive Cs+ will destabilize the perovskite structure, leading to rapid film decomposition in ambient air. Our results indicate that employing higher concentrations of Cs+, specifically 10 % and 15 %, leads to superior performance and enhanced stability. Notably, the perovskite solar cell incorporating 10%-Cs exhibits larger grain sizes, uniform particle distribution, and its highest PCE achieves 16.41 %. Our research provides a straightforward and cost-effective strategy for improving the performance of inverted perovskite solar cells utilizing triple cations.

Theory of piezotronic and piezo-phototronic effects on high performance perovskite solar cells

Piezotronic and piezo-phototronic effects can effectively modulate the Schottky barrier height (SBH) of the metal-semiconductor contact and the built-in electric field. Most models focus on the built-in electric field of perovskite solar cells, and polarization-modulated SBH is missing. We investigated piezotronic and piezo-phototronic effects on the Schottky barrier and built-in electric field of perovskite solar cells. A model of the surface potential induced by polarization was developed. The analytical and numerical results are calculated for perovskite solar cells. We found that the piezo-phototronic effect can significantly increase the performance of perovskite solar cells by reducing the height of the Schottky barrier. This model not only provides a fundamental physical picture of the piezotronic and piezo-phototronic effect on perovskite solar cells, but also paves a new path to develop high-efficiency perovskite solar cells.

Efficient and stable perovskite solar cells via oxalic acid doped SnO2 nanocrystals with surface-defect passivation

The electron extraction and transfer play a crucial role in high performance of perovskite solar cells (PSCs). Tin dioxide (SnO2), with the high electrical conductivity and low photocatalytic activity, has been reported to be one of the most advantageous electron-transporting layers (ETL) in PSCs. However, a large number of non-radiative recombination defects have been reported in SnO2, which are attributed to the low tunability and lower dispersibility. Here, we propose a ligand-assisted tuning strategy based on the oxalic acid (OA) modification to control the SnO2 film and interfacial structure. This strategy can effectively inhibit the particle aggregation of SnO2 film. In addition, the bonding interaction between CO in the ligand and Sn in SnO2 and Pb atoms in the perovskite reduces the interfacial contact impedance and enhances the electron extraction. As a result, an impressive PCE of 22.68 %, a fill factor exceeding 0.82 and a Voc of 1.15 V were successfully obtained. In addition, the unencapsulated PSCs can maintain an initial efficiency of 93 % upon exposure to ambient air for 500 h.

Enhancing efficiency and stability of perovskite solar cells with Bi2Te3 interlayer: insights from SCAPS simulation

Perovskite solar cells (PSCs) have gained much interest due to their high power conversion efficiencies (PCE). Affordable, accessible, and efficient solar energy is crucial for a sustainable and clean future. In this article, we optimized PSC efficiency and performance with an interlayer (IL) of Bi2Te3 (BT). Cell performance and efficiency were improved by incorporating BT IL with varied thicknesses. BT IL promotes electron transport while protecting the underlying structure from chemical instability, improving device performance. This simple and low-cost technology for producing efficient and stable all-inorganic PSC holds considerable potential as a next-generation renewable energy source. The main focus is optimizing all-inorganic PSC using Solar Cell Simulator Capacitance software (SCAPS). We systematically explore the influence of BT thickness and defect densities on the device performance. The impact of charge carrier transport and overall photovoltaic performance is studied. Our findings reveal that introducing the BT IL leads to improved charge extraction, reduced recombination losses, and enhanced stability in the PSC. The optimized device configuration significantly enhances PCE compared to reference devices without BT IL. This study provides valuable insights into the potential use of BT ILs as a strategy to boost the efficiency and stability of PSCs.

On the dynamics of improved perovskite solar cells: Introducing SVM-DNN-GA algorithm to predict dynamical information

This study presents an innovative approach to enhancing the performance of perovskite solar cells through the integration of a functionally graded triply periodic minimal surface (FG-TPMS) layer. The research focuses on the mechanical and vibrational characteristics of doubly curved panels embedded with three distinct iterations of the FG-TPMS model: the primitive, gyroid, and wrapped package graph (IWP). By employing higher-order shear deformation theory (HSDT), the analysis accounts for the complex geometrical and material gradations within the FG-TPMS structures. An advanced analytical method utilizing trigonometric functions is developed to accurately predict the natural frequencies and mode shapes of these novel composite structures. In order to assess the vibrations of TPMS-reinforced perovskite solar cells surrounded by an elastic foundation, this work proposes the implementation of a novel Support Vector Machine (SVM)-deep neural network (DNN)-Genetic Algorithm (GA) employing mathematical modeling datasets. Using the SVM-DNN-GA algorithm, predicted accuracy is improved. In order to simulate and forecast the vibrational behavior of the reinforced solar cells, the integrated methodology makes use of the advantages of each technique. The results indicate that the integration of FG-TPMS layers significantly enhances the mechanical stability of the perovskite solar cells. The application of HSDT reveals detailed insights into the dynamic responses of the doubly curved panels, highlighting the potential for fine-tuning their vibrational characteristics to further improve solar cell performance. This research underscores the potential of FG-TPMS structures in advancing solar cell technology, providing a foundation for future studies to explore the integration of complex geometries and material gradations in photovoltaic applications.

From Wide-Bandgap to Narrow-Bandgap Perovskite: Applications from Single-Junction to Tandem Optoelectronics.

As perovskite solar device is burgeoning photoelectronic device, numerous studies to optimize perovskite solar device have been demonstrated. Amongst various advantages from perovskite light absorbing layer, attractive property of tunable bandgap allowed perovskite to be adopted in many different fields. Easily tunable bandgap property of perovskite opened the wide application and to get the most out of its potential, many researchers contributed as well. By precursor composition engineering, narrow bandgap with bandgap of less than 1.4 eV and wide bandgap with bandgap of more than 1.7 eV were achieved. Optimization of both narrow and wide bandgap perovskite solar cell could pave the way to all-perovskite tandem solar cell which is combination of top cell with wide bandgap and bottom cell with narrow bandgap. This review highlights numerous efforts to advance device performance of both narrow and wide bandgap perovskite solar cell and how they challenged the issues. And finally, efforts to operate and utilize all-tandem perovskite device in real world will be discussed.

DFT and SCAPS-1D based optimization study of double perovskite Cs2AuBiCl6 solar cells utilizing different charge transport layers

In this work, halide double perovskite (HDP) Cs2AuBiCl6 is investigated as potential absorber material in the perovskite solar cell (PSC) using the SCAPS-1D tool. WIEN2K code is utilized for computation to study the structural, and optoelectronic properties of Cs2AuBiCl6. The calculated bandgap of the Cs2AuBiCl6 is found to be ∼1.09 eV using TB-mBJ (Tran-Blaha modified Becke-Johnson) potential. Performance of the Cs2AuBiCl6-based PSC is enhanced by improving the properties of charge transport layers and the perovskite (PVSK) absorber layer. Combination of Electron Transport Layers (ETLs) such as WS2, PCBM, ZnO, TiO2, and C60 and Hole Transport Layers (HTLs) such as Cu2O, P3HT, CuSCN, PEDOT: PSS, Spiro-OMeTAD, CuSbS2 are evaluated to find the best ETLs and HTLs among the above-mentioned materials. Also, further study is performed on the five best devices with five different ETLs using CuSbS2 as the HTL. Apart from that, the energy band diagrams of the best five devices are investigated. Further, a performance study is done on those best five devices through the impact of the variations in thickness of ETL, defect density, thickness of Cs2AuBiCl6 layer, shunt, and series resistances of device. After all the optimizations, the best PCEs of these five optimized devices are found to be 21.16 %, 21.14 %, 20.84 %, 20.79 %, and 14.75 % with CuSbS2 as HTL, and C60, WS2, TiO2, PCBM, and ZnO as ETLs, respectively. Furthermore, current density-voltage (J-V) and quantum efficiency (QE) characteristics of the five devices are analyzed to determine the potential of Cs2AuBiCl6 as a viable material for non-leaded PSCs.

Effect of Interfacial Ionic Defects in Perovskite Solar Cells and their Mitigation Mechanism: A Comprehensive Theoretical Analysis with Experimental Validation

AbstractInterfacial ionic defects in perovskite solar cells (PSCs) significantly influence the efficiency and long‐term stability. In this study, primarily simulation‐assisted analyses are conducted to explore the capacitive effect of these defects on the performance of PSCs through impedance analysis. Simulated data indicate a decrease in capacitance with increasing frequency, leading to a higher built‐in potential (ΔVbi = 150 mV). Moreover, an increase in capacitance with increasing light intensity is observed. Additionally, reducing the ionic defect concentration at the interfaces (from 1019 to 1016 cm−3) results in more significant band bending and a higher Vbi. Potential solutions to mitigate interfacial ionic defects, including doping at transport layer interfaces are proposed. Doping at both interfaces introduces an energy spike (valence band offset) of 0.21 eV and a cliff (conduction band offset) of 0.16 eV, respectively, for holes and electrons, leading to an improvement in the open circuit voltage (VOC). Finally, experimental results demonstrate a notable enhancement in VOC of 0.04 V with the introduction of Li+ doping at the electron transport layer/perovskite interface. These findings provide essential perceptions for effectively mitigating the effect of interfacial ionic defects on the performance of PSCs and enhance their overall performance.

Unraveling Differences in the Effects of Ammonium/Amine-Based Additives on the Performance and Stability of Inverted Perovskite Solar Cells.

Additive engineering, with its excellent ability to passivate bulk or surface perovskite defects, has become a common strategy to improve the performance and stability of perovskite solar cells (PVSCs). Among the various additives reported so far, ammonium salts are considered an important branch. It is worth noting that although both ammonium-based additives (R-NH3 +) and amine-based additives (R-NH2) are derivatives of ammonia (NH3), the functions of the two can be easily confused due to their structural similarities. Moreover, there is no comprehensive comparative analysis of them in the literature. Here, the differences between phenethylammonium iodide (PEA+) and phenethylamine (PEA) additives are revealed experimentally and theoretically. The results clearly show that PEA outperforms PEA+ in terms of device performance and stability based on the following three factors: i) PEA's defect passivation capability is superior to that of PEA+; ii) PEA has better hydrophobicity to hinder water ingress; and iii) PEA completely improves the stability of PVSCs by enhancing thermal stability and inhibiting iodide migration in perovskite more effectively than PEA+. As a result, the power conversion efficiency (PCE) of the inverted methylammonium triiodide (MAPbI3) device using PEA increases by ≈15% to over 21%. More importantly, this device exhibits greater ability to prevent water invasion, thermal-induce degradation, and inhibit iodide ion migration, resulting in better long-term stability.

(Invited) Ion Migration Influencing Perovskite Solar Cell Performance and Stability

The thermodynamic and redox properties of halide perovskites provide a strong driving force for hole trapping and oxidation of iodide species. When in contact with a non-polar solvent, the migration of iodine species is further extended to expulsion of iodine from the perovskite film. Thus, the mobility of halides and their susceptibility to hole-induced oxidation play a crucial role in determining the long-term stability of metal halide perovskite solar cells. When Ruddlesden-Popper 2D mixed-halide perovskite films with spacer cations such as butylammonium are introduced into three-dimensional (3D) perovskite films, they can stabilize them against moisture-induced degradation at room temperature. While such passivation of 3D perovskites using 2D perovskites has been reported widely, the instability of the 2D/3D interface during long term solar cell operation can be problematic, especially at higher temperatures. The cation migration under light and heat can significantly alter the 2D/3D interface, thus affecting the solar cell performance. We have now probed the cation migration between 2D and 3D perovskites by physically pairing X PbI (X=butylammonium BA, oleylammonium OA, or phenethylammonium PEA) 2D film and (CH3)PbI3 3D film at different temperatures by recording changes in the absorption and emission spectra. Thus, suppression of halide ion migration as well as cation migration remains a key factor in achieving long term stability and improving efficiency of perovskite solar cells and light emitting devices.

Nitrogen-rich carbon dots as the antisolvent additive for perovskite-based photovoltaic devices

Solution-processed perovskite solar cells (PSCs) have demonstrated a tremendous growth in power conversion efficiency (PCE). A high-quality, defect-free perovskite-based active layer is a key point to enhance PSC performance. Introduction of additives and interlayers have proved to be an effective tool to passivate surface defects, control crystal growth, and improve PSC stability. Antisolvent engineering has emerged recently as a new approach, which aims to adjust perovskite layer properties and enhance the PCE and stability of PSC devices. Here, we demonstrate that carbon dots (CDs) may serve as a prospective additive for antisolvent engineering. Nitrogen-rich amphiphilic CDs were synthesized from amines by a solvothermal method and used as an additive to chlorobenzene for a perovskite layer fabrication. The interaction between perovskite and functional groups in CDs promotes improved crystallization of an active perovskite layer and defects passivation, bringing higher PSCs efficiency, stability, and suppressed hysteresis. Under optimized CD concentration, the maximum PCE increased by 34% due to the improved short-circuit current and fill factor, and the device maintains 87% of its initial efficiency after 6 d of storage under ambient conditions.

Enhancing efficiency and performance of Cs2TiI6-based perovskite solar cells through extensive optimization: A numerical approach

The commercial production of lead-based perovskite solar cells (PSCs) is hindered due to toxicity difficulty and all Ti-based all-inorganic PSCs may give a practical solution to these problems. This work optimizes the different layers of a PSC based on the Cs2TiI6 absorber layer. In order to produce four unique structures, ten distinct HTLs are considered to identify the best HTL, and after that four ETLs are utilized. These structures are then optimized using SCAPS 1D simulation software. The thickness of the absorber and electron transport layer (ETL), as well as the acceptor and defect density of the absorber, and the acceptor density of the hole transport layer (HTL), were optimized sequentially. After the optimization, the best PCE of 28.03 % along with VOC, JSC, and FF of 1.11 V, 28.39 mA/cm2, and 89.01 % were found, correspondingly for the structure of FTO/SnS2/Cs2TiI6/MoTe2/Au. Additionally, the effects of temperature, series resistance, and shunt resistance were investigated with regard to the four most promising devices. The generation and recombination rates, together with the reported properties of current-voltage density (J-V) and quantum efficiency (QE), are also relevant to the first and last optimized devices in the four-device investigation.

Phase‐Pure Iron Pyrite Nanocrystals as Air‐Stable Hole‐Transport Materials for Low‐Cost Perovskite Solar Cells

Spiro‐OMeTAD is a commonly used organic hole‐transport material (HTM) in MAPbI3‐based perovskite solar cells (PSCs) for achieving high efficiency. However, its hydrophilic nature compromises device stability and performance reproducibility, especially under ambient conditions. In this study, PSCs are fabricated under ambient conditions, and phase‐pure iron pyrite nanocrystals (FeS2 NCs) are synthesized and utilized as HTM. Using iron pyrite as the HTM leads to a 22% increase in device short‐circuit current density (JSC) compared to Spiro‐OMeTAD, resulting in enhanced PSC performance. This confirms FeS2 NCs as a promising HTM for PSCs. Iron pyrite improves the extraction of photogenerated charge carriers compared to Spiro‐OMeTAD, indicating a superior extraction layer. Furthermore, the longer stability of the iron pyrite layer under humid conditions is compared to the Spiro‐OMeTAD layer, as demonstrated by contact angle measurements. This improvement helps prevent humidity‐induced degradation of the perovskite layer. Transient photocurrent studies under reverse bias conditions reveal fewer defects at the perovskite/iron pyrite interface, suggesting a defect passivation effect of FeS2 NCs. This study demonstrates that iron pyrite can serve as an effective HTM to enhance the performance and stability of low‐cost PSCs fabricated under ambient conditions.