Development Of Perovskite Solar Cells Research Articles

Side Chain Functional Molecule Additives for Efficient and Stable Perovskite Solar Cells

AbstractIn the commercial development of perovskite solar cells, the main challenge lies in achieving efficient devices with high stability. Additive engineering in polycrystalline perovskites is considered as an effective approach to address this challenge by passivating surface defects and reducing carrier losses associated with these defects. In this work, the passivation effect of molecules with different side chain groups on perovskites and the role of binding energy in mitigating carrier loss are studied. The findings reveal that the thiophene group is particularly effective in passivating defects and enhancing hole transport. Consequently, devices treated with 2‐thienylmethylamine hydrochloride (TMAC) demonstrate a champion power conversion efficiency (PCE) of 24.63%. Furthermore, these TMAC‐treated devices exhibit remarkable stability, maintaining over 93.13% of their initial efficiencies after 1200 h of continuous illumination under maximum power point tracking (MPPT). This research presents a pathway to enhance the optoelectronic performance and stability of perovskite solar cells.

Simultaneous Ultraviolet Conversion and Defect Passivation Stabilize Efficient and Operational Durable Perovskite Solar Cells

AbstractDespite the swift development in perovskite solar cells (PSCs), great concerns regarding environmental vulnerability propose a big challenge for their long‐term operational stability. Herein, a novel functionalized ultraviolet (UV) conversion small molecule, Coumarin 153 (C153), is judiciously introduced into perovskite precursor to effectively enhance device efficiency and operational stability against UV radiation. It is found that the uncoordinated Pb2+ and A‐site vacancies of perovskite can be successfully fixed through Lewis acid–base coordination and hydrogen bonding upon C153 treatment, resulting in a stabilized structure with remarkably reduced intrinsic defects. Concurrently, the incremental visible light absorption derived from the down‐conversion effect of C153 molecules together with the optimized energy level arrangement contribute to the substantially enhanced photocurrent of the device. As a result, the resultant device delivers a champion efficiency of 24.73%, accompanied by greatly improved operational stability against environments, with retaining over 90% of initial PCE for ≈380, ≈1400, and 1710 h aging under continuous UV radiation, heating stress, and illumination, respectively. This work provides an effective and feasible strategy toward high‐efficiency and environment‐stable PSCs.

Artificial Intelligence-Based, Wavelet-Aided Prediction of Long-Term Outdoor Performance of Perovskite Solar Cells.

The commercial development of perovskite solar cells (PSCs) has been significantly delayed by the constraint of performing time-consuming degradation studies under real outdoor conditions. These are necessary steps to determine the device lifetime, an area where PSCs traditionally suffer. In this work, we demonstrate that the outdoor degradation behavior of PSCs can be predicted by employing accelerated indoor stability analyses. The prediction was possible using a swift and accurate pipeline of machine learning algorithms and mathematical decompositions. By training the algorithms with different indoor stability data sets, we can determine the most relevant stress factors, thereby shedding light on the outdoor degradation pathways. Our methodology is not specific to PSCs and can be extended to other PV technologies where degradation and its mechanisms are crucial elements of their widespread adoption.

Phenyltrimethylammonium chloride additive for highly efficient and stable FAPbI3 perovskite solar cells

Formamidinium lead triiodide (FAPbI3)-rich perovskite absorbers have emerged as the frontrunners for the development of perovskite solar cells (PSCs), but pristine FAPbI3 absorber exhibits phase instability because of external stressors during device manufacture and operation. In this work, we systematically study the function of a trace amount of phenyltrimethylammonium chloride (PTAC) additive in FAPbI3-based perovskites. The introduced PTAC have a strong electrostatic interaction with perovskite because of the coordination of electron-rich benzene ring unit and under-coordinated Pb2+, which leads to the decrease of the trap density and the release of the lattice strain. Simultaneously, the increased work function of modulated film optimizes the band alignment, promoting carrier transport and reducing nonradiative recombination, thereby improving the open-circuit voltages and fill factors. Consequently, the modulated PSCs achieve a champion power conversion efficiency of 24.51%, and exhibit much better stability by retaining 90% of their initial efficiency after 1000 hours constant illumination under maximum power point tracking measurement.

Ceiling of Barium Substitution for B-Site Cation in Organometal Halide Perovskite Solar Cells

Significant advancements have been made in the development of perovskite solar cells (PSCs) in recent years, resulting in increased efficiency rates. Nonetheless, the presence of lead within these cells has become a pressing concern. Our study investigates the correlation between tolerance of barium substitution and A-site cation composition through systematic analysis of morphology, crystal structure, optical property, and carrier dynamics. The results show that a high barium substitution ratio of 15 mol.% can be achieved by inducing 60 mol.% of a large A-site cation, formamidinium, into the methylammonium-based perovskite. The induction of large A-site cations in barium-substituted perovskite overcomes the imbalance between hole and electron diffusion lengths, resulting in an electron and a hole diffusion length of 395 nm and 440 nm, respectively. The champion device for 15 mol.% barium-substituted perovskite, FA0.6MA0.4Pb0.85Ba0.15I3-yCly, achieves a PCE of 11.13%, which is the highest record for 15 mol.% of lead reduction. This study provides insights into the limitations of lead substitution in perovskite solar cells and highlights the ceiling for barium substitution ratio in mixed cation perovskite.

Lead‐Free All‐Inorganic Cesium Bismuth Iodide‐Based Perovskite Solar Cells: Recent Advances, Current Limitations, and Future Prospects

Remarkable achievements have been made in the development of perovskite solar cells (PSCs) with a rapidly boosting rate of power conversion efficiencies (PCEs) from 3.8% to 26.1%. Nevertheless, the toxicity of lead (Pb) elements and the hygroscopicity of organic cations in high‐efficiency PSCs severely hamper the commercialization of this technology. Consequently, Pb‐free all‐inorganic PSCs have received increasing attention recently to resolve the above‐mentioned toxicity and instability problems. Among various Pb‐free all‐inorganic halide perovskites, cesium bismuth iodide (CBI)‐based perovskites have gained particular attention as light absorbers in PSCs due to the tunable/small bandgaps, long carrier diffusion length/lifetime, and superb sunlight absorption coefficients. Nevertheless, the PCEs of CBI‐based PSCs are still far away from Pb‐based organic–inorganic counterparts because of the low structural dimensions and inferior perovskite film quality. Herein, the recent advances of CBI‐based perovskites as light‐absorbing materials in Pb‐free all‐inorganic PSCs are reviewed by emphasizing the distinct structural/optical/electronic properties and currently existing limitations. Additionally, several distinct strategies to boost the PCEs and robusticity of CBI‐based PSCs are presented. Finally, the unsolved key problems and future directions of CBI‐based PSCs are proposed, aiming to provide important insights for the further development of CBI‐based PSCs to realize sustainable, nontoxic, high‐performance perovskite photovoltaics.

High Open‐Circuit Voltage (1.197 V) in Large‐Area (1 cm2) Inverted Perovskite Solar Cell via Interface Planarization and Highly Polar Self‐Assembled Monolayer

AbstractThe efficiency loss caused by area scaling is one of the key factors hindering the industrial development of perovskite solar cells. The energy loss and contact issues in the buried interface are the main reasons. Here, a new self‐assembled monolayer (SAM), Ph‐4PACz, with a large dipole moment (2.32 D) is obtained . It is found that Ph‐4PACz with high polarity can improve the band alignment and minimize the energy loss , resulting in an open‐circuit voltage (Voc) as high as 1.2 V for 1.55 eV perovskite. However, when applied to large‐area devices, the fill factor (FF) still suffered from significant attenuation. Therefore, alumina nanoparticles (Al2O3‐NPs) are introduced to the interface between Ph‐4PACz and rough FTO substrate to further improve the flatness , resulting in a conformal perovskite film with almost no voids in the buried interface, thus promoting low exciton binding energy, fast hot‐carrier extraction and low non‐radiative recombination. The final devices achieved a small‐area power conversion efficiency (PCE) of 25.60% and a large‐area (1 cm2) PCE of 24.61% (certified at 24.48%), which represents one of the highest PCE for single device ≥ 1 cm2 area. Additionally, mini‐modules and stability testing are also carried out to demonstrate the feasibility of commercialization.

Titanium Carbide (Ti3C2Tx) MXene as Efficient Electron/Hole Transport Material for Perovskite Solar Cells and Electrode Material for Electrochemical Biosensors/Non-Biosensors Applications.

Recently, two-dimensional (2D) MXenes materials have received enormous attention because of their excellent physiochemical properties such as high carrier mobility, metallic electrical conductivity, mechanical properties, transparency, and tunable work function. MXenes play a significant role as additives, charge transfer layers, and conductive electrodes for optoelectronic applications. Particularly, titanium carbide (Ti3C2Tx) MXene demonstrates excellent optoelectronic features, tunable work function, good electron affinity, and high conductivity. The Ti3C2Tx has been widely used as electron transport (ETL) or hole transport layers (HTL) in the development of perovskite solar cells (PSCs). Additionally, Ti3C2Tx has excellent electrochemical properties and has been widely explored as sensing material for the development of electrochemical biosensors. In this review article, we have summarized the recent advances in the development of the PSCs using Ti3C2Tx MXene as ETL and HTL. We have also compiled the recent progress in the fabrication of biosensors using Ti3C2Tx-based electrode materials. We believed that the present mini review article would be useful to provide a deep understanding, and comprehensive insight into the research status.

A Review of the Technological Advances in the Design of Highly Efficient Perovskite Solar Cells

The search for renewable and sustainable energy for energy security and better environmental protection against hazardous emissions from petro-based fuels has gained significant momentum in the last decade. Towards this end, energy from the sun has proven to be reliable and inexhaustible. Therefore, better light harvesting technologies have to be sought. Herein, the current trends in the development of perovskite solar cells with a focus on device engineering, band alignment, device fabrication with superior light harvesting properties, and numerical simulation of solar cell architectures are critically reviewed. This work will form the basis for future scientist to have a better scientific background on the design of highly efficient solar cell devices, which are cost-effective to fabricate, highly stable, and eco-friendly. This review presents thorough essential information on perovskite solar cell technology and tracks methodically their technological performance overtime. The photovoltaic (PV) technology can help to reduce pollution related to greenhouse gas emissions, criterion pollutant emissions, and emissions from heavy metals and radioactive species by nearly 90%. Following the introduction of highly efficient perovskite solar cell (PSC) technologies, the problems associated with stability, short life-time and lead-based perovskite solar cell configurations have significantly been minimized. The fabrication and simulation of perovskite solar cells has been made possible with advanced technologies and state-of-the-art computational codes. Furthermore, device simulation strategies have lately been used to understand, select appropriate materials, and gain insights into solar cell devices’ physical behavior in order to improve their performances. Numerical simulation softwares such as the 1-dimenional solar cell capacitance simulator (SCAPS-1D), Silvaco ATLAS, and wx-analysis of microelectronic and photonic structures (wxAMPS) used to understand the device engineering of solar cells are critically discussed. Because of the need to produce charge collection selectivity, hole transport materials (HTMs) as well as electron transport materials (ETMs) constitute essential PSC components. In this work, the synthesis of inorganic HTMs, as well as their characteristics and uses in various PSCs comprising mesoporous and planar designs, are explored in detail. It is anticipated that the performance of inorganic HTLs on PSCs would encourage further research which will have a significant influence on the future designs and fabrication of highly efficient solar cells.

Organolead halide perovskites: Synthetic routes, structural features, and their potential in the development of photovoltaic

Abstract About 13 TW of energy is needed to sustain the lifestyle of people worldwide but an additional 10 TW clean energy will be required by 2050. The increase in the world population and the demand for energy that rely on fossil fuels has resulted in global warming that necessitates the need for alternative energy such as solar. Solar energy is abundant and readily available, and its use will contribute to sustainable development. Metal halide perovskites are promising materials for the development of next-generation solar cells. The power conversion efficiency (PCE) of 25.8% obtained for organolead halide perovskite is close to the polycrystalline solar cell’s efficiency at 26.3% and these materials offer great prospects for future photovoltaic development. To approach the theoretical efficiency limit, it is very important to study the development of perovskite solar cells in terms of material composition, fabrication techniques, and device architectures with emphasis on charge transport layers and electrodes. Limitations to PCE and stability of perovskites, optoelectronic properties, lifetime and stability, wide-scale applications, components of the perovskites solar cell, the standard for testing conditions for good stability and its evolution into the lower layered perovskite solar cells were examined in the current review.

Performance prediction and optimization of perovskite solar cells based on the Bayesian approach

The development of perovskite solar cells (PSCs) has received much attention in recent years, but material selection schemes based on trial-and-error methods have made the enhancement of perovskite solar cell performance a huge challenge. Here, we propose a machine learning framework to predict the Photoelectric conversion efficiency (PCE) of PSCs with high speed and accuracy and use a Bayesian algorithm to inverse predict the optimal values of the underlying parameters (band gap, thickness of each layer, defect density, etc.) of PSC devices. Four different machine learning models, including the Extremely Randomized Trees (ExtRa Trees), k-nearest neighbor (KNN), light gradient boosting machine (LGBM), and random forest regression (RF) were adopted for training, with the ExtRa Trees model giving the best prediction performance (R2 = 0.71). In addition interpretable machine learning was applied to extract the performance-structure relationship for the PSCs. A Bayesian approach was used to rapidly derive optimal values for the cell device parameters at a PCE of 23%, which greatly accelerated the PSC manufacturing process. This work demonstrates the great potential of machine learning to accelerate the development of PSCs.

Interpretable machine learning assisted multi-objective optimization design for small molecule hole transport materials

Small molecule hole transport materials (SM-HTMs) play an important role in the development of perovskite solar cells (PSCs) due to the simple structure and excellent photoelectric performance. Herein, we established interpretable models for designing materials with high hole mobility (μ) and absolute hardness (η). The μ and η models were constructed by Gradient Boosting Regression (GBR) due to the better performances. The coefficient of determination (R2) for leave-one-out cross validation (LOOCV) and the test set are 0.86 and 0.86 in μ model, 0.84 and 0.89 in η model, respectively. SHapley Additive exPlanations (SHAP) analysis reveals that higher μ are more likely to be obtained with fewer C–O and N-O pairs at topological distance 9, and molecules with high degree of cyclization and less polar fragments might have higher η. New groups were designed based on the strategies and used to generate 785 virtual samples. Finally, 35 promising candidates (μ > 10−1.54 cm2 V−1 s−1 and η > 2.71 eV) with high synthesizability were screened out using high-throughput screening and pattern recognition. Our work provides an effective way to accelerate the design of prominent SM-HTMs.

Modification of Hydrophobic Self‐Assembled Monolayers with Nanoparticles for Improved Wettability and Enhanced Carrier Lifetimes Over Large Areas in Perovskite Solar Cells

The development of perovskite solar cells (PSCs) with low recombination losses at low processing temperatures is an area of growing research interest as it enables compatibility with roll‐to‐roll processing on flexible substrates as well as with tandem solar cells. The inverted or p–i–n device architecture has emerged as the most promising PSC configuration due to the possibility of using low‐temperature processable organic hole‐transport layers and more recently, self‐assembled monolayers such as [4‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl)butyl]phosphonic acid (Me‐4PACz). However, devices incorporating these interlayers suffer from poor wettability of the precursor leading to pin hole formation and poor device yield. Herein, the use of alumina nanoparticles (Al2O3 nanoparticles (NPs)) for pinning the perovskite precursor on Me‐4PACz is demonstrated, thereby improving the device yield. While similar wettability enhancements can also be achieved by using poly[(9,9‐bis(3′‐((N,N‐dimethyl)‐N‐ethylammonium)‐propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)]dibromide (PFN‐Br), a widely employed surface modifier, the incorporation of Al2O3 NPs results in significantly enhanced Shockley–Read–Hall recombination lifetimes exceeding 3 μs, which is higher than those on films coated directly on Me‐4PACz and on PFN‐Br‐modified Me‐4PACz. This translates to a champion power conversion efficiency of 19.9% for PSCs fabricated on Me‐4PACz modified with Al2O3, which is a ≈20% improvement compared to the champion device fabricated on PFN‐Br‐modified Me‐4PACz.

A2BB’X6/ABX3-type High-performance perovskites screening based on ensemble learning and high throughput screening

In this work, we have built a complete set of the ensemble learning model through data cleaning, feature engineering, model training, and evaluation. The model has predicted the formation energy (E_form), energy above hull (E_hull), and band gap of perovskites with an accuracy close to that of the first-principles calculation of a Mean Absolute Error of 0.146 eV, 0.041 eV, and 0.396 eV, respectively. Through the model, we successfully screened 614 candidates with stable structures and suitable band gaps (1.34 eV ∼ 1.5 eV) from 1,569,248 perovskites. To verify the robustness and generalizability of our ensemble learning model and facilitate future researchers' exploration of high-performance perovskites. we selected the most widely used bromide perovskite and two new perovskites (sulfides and oxides) with excellent optoelectronic properties for further DFT validation. They all exhibit excellent structural stability, thermodynamic stability, and suitable band gaps, among which Cs2TlPBr6 and Pb2RhPaS6 also have direct band gaps, low surface work function, and low effective masses, which are expected to be candidates for high-performance perovskite solar cells. Our proposed ensemble learning model enables high-precision prediction of perovskite performance in an “inexpensive” way, greatly reducing the design cycle of perovskite solar cells and promoting the application and development of perovskite solar cells.

SCAPS simulation and DFT study of lead-free perovskite solar cells based on CsGeI3

With the rapid development of perovskite solar cells (PSCs), environmentally friendly germanium-based PSCs have begun to appear in people's vision. We have designed a perovskite solar cell structure consisting of FTO/Cd0.5Zn0.5S/CsGeI3/MoO3/Au. Our study focused on analyzing the impact of various factors such as the absorption layer, electron transport layer (ETL), hole transport layer (HTL), interfacial defect layer (IDL), and temperature, on device performance. We optimized various parameters of the device, and as a result, the final PCE reached an impressive 35.91%. In addition, we conducted an analysis of the perovskite absorber layer using density functional theory (DFT) and investigated the function of Ge atoms in the perovskite absorber layer. The results show that, for HTL, altering the doping concentration of the ETL has a more significant impact on PSCs. When the operating temperature exceeds 300K, only the short-circuit current (Jsc) increases. When the defect density exceeds 1013cm−3, the rate of carrier recombination begins to increase significantly, along with the interface defect layer. We also analyzed the energy band, density of states, charge density difference, charge population, and elastic constants of the absorption layer using density functional theory (DFT). The results indicate that Ge atoms play a crucial role in photon absorption and photocurrent generation, which is a significant factor contributing to the high power conversion efficiency of germanium-based PSCs. Due to the transfer of electric charge from the Ge atom to the periphery of the I atom and the hybridization between the Ge-4p and I-5p orbitals, the Ge–I bond is formed and stabilized. Finally, the calculation of elastic constants shows that CsGeI3 is a stable mechanical structure.

Nickel-Doped Graphite and Fusible Alloy Bilayer Back Electrode for Vacuum-Free Perovskite Solar Cells.

With the rapid development of perovskite solar cells (PSCs), lowering fabrication costs for PSCs has become a prominent challenge for commercialization. At present, gold is commonly used as the back metal electrode in state-of-the-art n-i-p structured PSCs due to its compatible work function, chemical inertness, and high conductivity. However, the high cost of gold and the expensive and time-consuming vacuum-based thin-film coating facilities may impede large-scale industrialization of PSCs. Here, we report a bilayer back electrode configuration consisting of an Ni-doped natural graphite layer with a fusible Bi-In alloy. This back electrode can be deposited in a vacuum-free approach and enables PSCs with a power conversion efficiency of 21.0%. These inexpensive materials and facile ambient fabrication techniques provide an appealing disruptive solution to low-cost PSC industrialization.

Volatile Dual‐Solvent Assisted Intermediate Phase Regulation for Anti‐Solvent‐Free Perovskite Photovoltaics

AbstractThe unprecedented development of perovskite solar cells (PSCs) makes them one of the most promising candidates for terawatt‐scale green energy production with low cost. However, the high boiling point solvents during the solution‐processed film deposition cause anisotropic crystal growth and toxic solvent vapor during high‐throughput manufacturing. Here, a dual‐component green solvent consisting of isopropyl acetate and acetonitrile is proposed to form a volatile perovskite precursor, which can realize the high‐quality perovskite thin film deposition by intermediate phase regulation. A room‐temperature stable perovskite intermediate phase is constructed with the engagement of isopropyl acetate as co‐solvent, which suppresses the exploding nucleation rate in volatile perovskite precursor, providing a fine grain growth rate and wide processing window in scalable film deposition. The corresponding PSCs fabricated by blade coating without anti‐solvents or gas quenching achieve power conversion efficiency (PCE) of 16.37 % and 15.29 % for the areas of 14.08 cm2 and 37.83 cm2, respectively.

Volatile Dual-Solvent Assisted Intermediate Phase Regulation for Anti-Solvent-Free Perovskite Photovoltaics.

The unprecedented development of perovskite solar cells (PSCs) makes them one of the most promising candidates for terawatt-scale green energy production with low cost. However, the high boiling point solvents during the solution-processed film deposition cause anisotropic crystal growth and toxic solvent vapor during high-throughput manufacturing. Here, a dual-component green solvent consisting of isopropyl acetate and acetonitrile is proposed to form a volatile perovskite precursor, which can realize the high-quality perovskite thin film deposition by intermediate phase regulation. A room-temperature stable perovskite intermediate phase is constructed with the engagement of isopropyl acetate as co-solvent, which suppresses the exploding nucleation rate in volatile perovskite precursor, providing a fine grain growth rate and wide processing window in scalable film deposition. The corresponding PSCs fabricated by blade coating without anti-solvents or gas quenching achieve power conversion efficiency (PCE) of 16.37% and 15.29% for the areas of 14.08 cm2 and 37.83 cm2, respectively.

Advances on the Application of Wide Band-Gap Insulating Materials in Perovskite Solar Cells.

In recent years, the development of perovskite solar cells (PSCs) is advancing rapidly with their recorded photoelectric conversion efficiency reaching 25.8%. However, for the commercialization of PSCs, it is also necessary to solve their stability issue. In order to improve the device performance, various additives and interface modification strategies have been proposed. While, in many cases, they can guarantee a significant increase in efficiency, but not ensure improved stability. Therefore, materials that improve the device efficiency and stability simultaneously are urgently needed. Some wide band-gap insulating materials with stable physical and chemical properties are promising alternative materials. In this review, the application of wide band-gap insulating materials in PSCs, including their preparation methods, working roles, and mechanisms are described, which will promote the commercial application of PSCs.

Development of High Efficiency, Spray-Coated Perovskite Solar Cells and Modules Using Additive-Engineered Porous PbI2 Films.

The development of anti-solvent free, scalable, and printable perovskite film is crucial to realizing the low-cost roll-to-roll development of perovskite solar cells (PSCs). Herein, large-area perovskite film fabrication is explored using a spray-assisted sequential deposition technique. How propylene carbonate (PC) solvent additive affects the transformation of lead halide (PbI2 ) into perovskite at room temperature is investigated. The result shows that PC-modified perovskite films exhibit a uniform, pinhole-free morphology with oriented grains compared with pristine perovskite films. The PC-modified perovskite film also has a prolonged fluorescence lifetime that indicates lower carrier recombination. The champion PSC devices based on PC-modified perovskite film realize a power conversion efficiency (PCE) of 20.5% and 19.3% at an active area (A) of 0.09 cm2 and 1 cm2 , respectively. The fabricated PSCs are stable and demonstrate ≥85% PCE retention following 60 days of exposure to ambient conditions. Furthermore, perovskite solar modules (A ≈ 13 cm2 ) that yield a PCE of 15.8% are fabricated. These results are among the best reported for the state-of-art spray-coated PSCs. Spray deposition coupled with a PC additive is highly promising for economical and high-output preparation of PSCs.