Commercialization Of Perovskite Solar Cells Research Articles

Impact of hole-transport layer materials on the field-induced degradation of p-i-n perovskite solar cells

The choice of hole-transport materials (HTMs) has a strong impact on electric field-induced degradation of perovskite solar cells (PSCs). Rational design of HTMs is necessary to make PSCs sufficiently stable for the targeted practical applications.

Multifunctional additive enables lead-adsorbing carbon electrodes for perovskite solar cells

Phosphate, being a single-component multifunctional additive, serves as a viable material for the carbon electrode in perovskite solar cells. This utilization ensures the device's performance and mitigates the risk of potential lead pollution.

Fullerene-C60 and PCBM as interlayers in regular and inverted lead-free PSCs using CH3NH3SnI3: an analysis of device performance and defect density dependence by SCAPS-1D.

One of the challenges hindering the commercialization of perovskite solar cells (PSCs) is the presence of toxic metals such as lead in their composition. Simulation studies using SCAPS-1D have already been conducted on lead-free PSCs to find optimized solar cell parameters, having tin as the primary candidate for replacing lead in perovskites. Here, we used fullerene-C60 and its derivative PCBM as interlayers in a lead-free tin-based PSC between the ETL (ZnO) and the perovskite MASI in both regular and inverted configurations of PSCs using SCAPS-1D software. To the best of our knowledge, this is the first simulation study reporting the impact of using fullerene-C60 and PCBM as interlayers in lead-free PSCs. The defect density (Nt) of the perovskite material is varied, allowing us to observe its influence on the power conversion efficiency (PCE). Using an Nt value of 1017 cm-3 without the interlayer, the PCE was 6.90% and 3.72% for regular and inverted devices. Using PCBM as an interlayer improves the efficiency of both simulated PSCs, achieving a maximum PCE of 8.11% and 5.26% for the regular and inverted configurations, respectively. Decreasing the Nt from 1017 cm-3 to 1016 cm-3 caused a significant increase in efficiency, reaching 13.38% (n-i-p) and 10.00% (p-i-n). Finally, using the optimized parameters and an ideal Nt value (1013 cm-3), both PSCs achieved a PCE close to 30%.

The impact of moisture on the stability and degradation of perovskites in solar cells

Efficiency and stability are the two most important factors in commercially scalable solar cells.

Cross-linking strategies for efficient and highly stable perovskite solar cells

This review summarizes recent developments on cross-linking strategies which have shown great potential in enhancing all-round stability of perovskite solar cells (PSCs) and provides guidance for further design of cross-linking molecules or approaches to promote the commercialization of PSCs.

Charged Hole‐Transporting Materials Based on Imidazolium for Defect Passivation in Inverted Perovskite Solar Cells

The hole‐transporting material (HTM) in perovskite solar cells (PSCs) provides an ideal interface with the perovskite layer for hole collection while influencing the perovskite crystalline structure and morphology. This article presents SIM and DIM, two new dopant‐free imidazolium‐based HTMs with charged units accompanied by counter ions that show the potential to function as ionic HTMs and ionic liquid additives and help improve the efficiency and stability of inverted PSCs. DIM‐based PSCs demonstrates exceptional performance with a high‐power conversion efficiency of 19.15%, attributed to improved passivation of perovskite interface defects. Furthermore, these new imidazolium salt‐based HTMs can be manufactured economically, making them a viable option for mass production and PSC commercialization.

Green Solvent Accelerates Spiro‐OMeTAD Oxidation for Efficient Perovskite Solar Cells

As one of the most widely used hole transport materials (HTMs) in optoelectronics devices, 2,2’,7,7’‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9‐spirobifluorene (spiro‐OMeTAD) has endowed perovskite solar cells (PSCs) with record power conversion efficiencies (PCEs). However, the long oxidation time in the ambient atmosphere is time‐consuming. Furthermore, commonly used solvents for spiro‐OMeTAD film processing such as chlorobenzene (CB) are toxic, which severely hinders the commercialization of PSCs. Herein, ethyl acetate (EA) serves as a superior green solvent alternative to the typical processing solvent, which substantially reduces the oxidation time of spiro‐OMeTAD. Without postoxidation treatment and any other additional oxidizing agents, the resultant device delivers a high PCE of 23.3%, significantly outperforming the CB‐based device. It is also the highest efficiency obtained from nonhalogenated solvent‐processed spiro‐OMeTAD. The electrostatic potential mapping demonstrates that the electron density at nitrogen atoms of EA‐processed spiro‐OMeTAD is more delocalized, leading to a faster oxidation. Furthermore, the processing solvent EA is a green solvent with low toxicity, and the amount of HTMs used in the fabrication of solar cells can be dramatically reduced. This study provides a new solution for processing spiro‐OMeTAD, which is ideal for the mass production of PSCs.

Tailoring the SnO2 Ink for Roll‐to‐Roll Manufacturing of Flexible Perovskite Solar Cells

Roll‐to‐roll (R2R) fabrication of high‐performance perovskite solar cells (PSCs) remains challenging for PSC commercialization. Herein, the R2R‐suitable electron transfer layer (ETL) SnO2 ink system for flexible PSCs is investigated. Water‐dispersed SnO2 inks, commonly used for flexible PSCs, form dewetting pinholes during R2R slot‐die coating owing to slower evaporation compared to spin coating. To prevent the dewetting of the pinhole, a low surface tension solvent (isopropyl alcohol, IPA) is added to the SnO2 ink. The IPA addition reduced surface tension, enhancing wetting behavior, but increased SnO2 nanoparticles (NPs) aggregation. Interestingly, the fabricated ETL films with highly aggregated SnO2 NPs are smooth, in contrast to the rough layers obtained via the spin‐coating process, owing to the high shear rate. Herein, NP aggregation and surface morphology are explored using Brownian dynamics simulations under shear conditions. Consequently, when the particles are agglomerated, the PSCs with slot‐die coating exhibit higher power conversion efficiency compared to ETL spin‐coated PSCs. Therefore, IPA addition to SnO2 ink is preferred for the R2R slot‐die process by improving the wetting properties and forming smooth films. In this study, a framework is provided for obtaining high‐quality films using the slot‐die coating of ETL and promotes the commercialization of PSCs.

Polymer Poly (Ethylene Oxide) Additive for High-Stability All-Inorganic CsPbI3−xBrx Perovskite Solar Cells

All-inorganic CsPbI3−xBrx perovskite solar cells (PSCs) are becoming increasingly mature due to their excellent optoelectronic properties. However, because of the poor environmental stability of the perovskite material, the device is susceptibly decomposed when exposed to moisture, high temperature, and high illumination. Therefore, a critical task is to address the problem of poor long-term stability in the environment, which serves as a significant obstacle impeding the commercialization of perovskite solar cells. This article introduces the incorporation of PEO into all-inorganic CsPbI3−xBrx perovskites with an advantageous thermal stability. PEO acts as a passivating agent near the grain boundary, and its high viscosity characteristics effectively improve the film-forming properties, leading to a substantial reduction in defects and to improving the surface uniformity. In addition, the grain boundaries that serve as water and oxygen penetration channels are filled, resulting in a substantial improvement in device stability. With 7.5 mg/mL PEO doping into CsPbI3−xBrx, the unencapsulated device maintained its original power conversion efficiency of 98% after being placed in a dark environment of 40% humidity and 25 °C for 10 days. Using PEO effectively enhanced the performance of the devices, with the highest PCE reaching 10.95%, significantly improving environmental stability.

Uracil Induced Simultaneously Strengthening Grain Boundaries and Interfaces Enables High-Performance Perovskite Solar Cells with Superior Operational Stability.

The operational stability is a huge obstacle to further commercialization of perovskite solar cells. To address this critical issue, in this work, uracil is introduced as a "binder" into the perovskite film to simultaneously improve the power conversion efficiency (PCE) and operational stability. Uracil can efficiently passivate defects and strengthen grain boundaries to enhance the stability of perovskite films. Moreover, the uracil also strengthens the interface between the perovskite and the Tin oxide (SnO2 ) electron transport layer to increase the binding force. The uracil-modified devices deliver a champion PCE of 24.23% (certificated 23.19%) with negligible hysteresis at active area of 0.0625 cm2 . In particular, the optimal device exhibits over 90% of its initial PCE after tracking for ≈6000 h at its maximum power point under continuous light, indicating its superior operational stability. Moreover, the devices also show great reproducibility in both PCE and operational stability.

Hole and electron transport materials: A review on recent progress in organic charge transport materials for efficient, stable, and scalable perovskite solar cells

Charge transporting materials are essential for fabricating stable and efficient perovskite solar cells. The high-temperature processing, surface defects, and low mobility are common issues in inorganic charge transport materials which can hinder the fabrication of low-cost, efficient, and stable perovskite solar cells. Dopants increase the processing cost of the hole transport materials. Surface defects are observed in the high-temperature processed inorganic electron transport materials. There is a need to develop organic compounds for charge transportation in perovskite solar cells. Herein, the advancements in the organic materials for charge transport in the perovskite solar cells are reviewed. The low-cost processing, better solubility, efficient charge mobility, tunable molecular orbitals, and better stability of organic compounds are some properties for their utilization as charge transport materials in perovskite solar cells. Organic small molecules, polymers, and phthalocyanine compounds can be utilized as dopant-free hole transport materials. Fullerene and non-fullerene derivatives like C60, C70, azaacenes, indacenodithiophene, polymers, and rylene diimides are promising electron transport materials. The functionality, engineering, charge transport properties, and device characteristics of different organic materials are discussed. The review will offer a forecast for improving device stability and efficiency in terms of architecture, engineering, and materials to realize the commercialization of perovskite solar cells soon.

Anion-π interactions suppress phase impurities in FAPbI3 solar cells.

Achieving both high efficiency and long-term stability is the key to the commercialization of perovskite solar cells (PSCs)1,2. However, the diversity of perovskite (ABX3) compositions and phases makes it challenging to fabricate high-quality films3-5. Perovskite formation relies on the reaction between AX and BX2, whereas most conventional methods for film-growth regulation are based solely on the interaction with the BX2 component. Herein, we demonstrate an alternative approach to modulate reaction kinetics by anion-π interaction between AX and hexafluorobenzene (HFB). Notably, these two approaches are independent but work together to establish 'dual-site regulation', which achieves a delicate control over the reaction between AX and BX2 without unwanted intermediates. The resultant formamidinium lead halides (FAPbI3) films exhibit fewer defects, redshifted absorption and high phase purity without detectable nanoscale δ phase. Consequently, we achieved PSCs with power conversion efficiency (PCE) up to 26.07% for a 0.08-cm2 device (25.8% certified) and 24.63% for a 1-cm2 device. The device also kept 94% of its initial PCE after maximum power point (MPP) tracking for 1,258 h under full-spectrum AM 1.5 G sunlight at 50 ± 5 °C. This method expands the range of chemical interactions that occur in perovskite precursors by exploring anion-π interactions and highlights the importance of the AX component as a new and effective working site to improved photovoltaic devices with high quality and phase purity.

Unleaded all-inorganic KSnI3 perovskite solar cell: A computational study

The implementation and commercialization of perovskite solar cells (PSCs) is hindered due to lead, which has a toxic nature. Although the PSCs based on the organic charge transport layers (CTLs) have achieved tremendous improvement in efficiency, they are not stable due to the structure of organic materials. In the present work, a theoretical study of the effect of inorganic CTLs on a KSnI3-based PSC is carried out using SCAPS software. The defect concentration of the layers and the interfaces, doping density and thickness of the layers, shunt, and series resistance of the device is optimized. Carbon is suggested as an affordable alternative to the state of art back contact material (BCM), gold. The stability of device performance with temperature is also established. The optimized solar cell (SC) showed a power conversion efficiency (PCE) of 9.28% and an excellent quantum efficiency(QE) in the visible region(99.59% at 400 nm to 78.58% at 650 nm). This study demonstrates the potential of KSnI3 as a perovskite material to achieve toxicity-free renewable energy using inorganic charge transport layers.

Multifunctional Self-Assembled Ionic Liquid Modified Rigid and Flexible Substrates for Efficient Simple-Structured Perovskite Solar Cells.

The advancement of electron transport layer (ETL)-free perovskite solar cells (PSCs) is crucial for the commercialization of PSCs. At present, the slow electron extraction and significant carrier recombination, related to the energy-level alignment at the FTO/perovskite interface, restrict the performance of ETL-free PSCs. The facile modification of bottom electrodes is pivotal for tackling these issues and stimulating the photovoltaic potential of perovskite. Herein, a cost-competitive and neoteric 1-hydroxyethyl-3-methylimidazolium chloride, [HOEtMIM]Cl, ionic liquid is employed to modify the surface of rigid and flexible electrodes, and thus enable an energetically well-aligned interface with perovskite layer via the electric dipole effects. The resulting barrier-free FTO/perovskite contact can tremendously ameliorate the electron extraction and collection, with mitigated nonradiative interfacial carrier recombination loss. Additionally, the lone pair on the nitrogen of the imidazole group passivates the surface defects of perovskite layers, and the chloride anion plays a role in the crystallinity improvement of perovskite. Leveraged by the [HOEtMIM]Cl modification, the resulting ETL-free rigid and flexible devices deliver an outstanding power conversion efficiency of 19.60 % and 15.57 %, along with the ameliorated hysteresis and long-term tenability. This finding highlights the drastic potential of the engineered [HOEtMIM]Cl in manufacturing stable and high-performance ETL-free PSCs for their scaled-up production.

Machine Learning in Perovskite Solar Cells: Recent Developments and Future Perspectives

Within a short period of time, perovskite solar cells (PSC) have attracted paramount research interests among the photovoltaic (PV) community. Usage of machine learning (ML) into PSC research is significantly accelerated their holistic understanding of device requisite properties. ML techniques are increasingly employed to discover stable perovskite materials, optimize device architecture and processing, and analyze PSC characterization data. This review provides an in‐depth exploration of ML applications in PSC advancement through an analysis of existing literature. The review commences with an introduction to the ML workflow, detailing each step, followed by concise overviews of perovskite materials and PSC operation. Later sections explore the diverse ways ML contributes to PSC development, which ranges from the optoelectronic property prediction of perovskites, discovery of novel perovskites, PSC device structure optimization, and comprehensive PSC analyses. The challenges impeding PSC commercialization are discussed, along with ML's potential to mitigate them. The review concludes by highlighting current limitations in employing ML for PSC research and suggests potential solutions. It also outlines prospective research directions for ML applications in PSC research, aiming to develop highly efficient and stable PSCs.

Mitigation of Potential‐Induced Degradation in Glass‐Encapsulated Perovskite Solar Cells Using a NiOx Barrier Layer

While the efficiency of perovskite solar cells has been increasing rapidly in recent years, studies on potential‐induced degradation (PID) in these devices have so far been very limited. Herein, the first successful mitigation of PID in glass‐encapsulated perovskite solar cells is reported. A thin NiOx blocking layer between the indium tin oxide and the self‐assembled monolayer is proposed to suppress the PID in these solar cells. Two groups of devices are fabricated, with and without the presence of the NiOx layer. When −1000 V is applied between the short‐circuited solar cell and the front glass pane, the original devices without NiOx only retain about 27% of the initial efficiency, and the modified devices with NiOx retained ≈65% after an extended stress duration of 96 h. The Na+ ions from the glass pane occupy NiOx vacancies under high voltage stress and, as a result, the Nax ion migration toward the perovskite layer is heavily suppressed due to the introduction of NiOx. The modified devices also demonstrate good long‐term stability, retaining more than 80% of initial efficiency after the PID stress test. The results of this work are helpful on the journey toward successful commercialization of perovskite solar cells.

Evaluation of the underwater stability of encapsulated perovskite solar cells

Metal halide perovskites have emerged as promising candidates for next-generation of photovoltaics, thanks to the excellent optoelectronic properties, low cost and facile fabrication. However, perovskite solar cells are still suffering from the poor stability, mainly, limited by the severe degradation after contact with water and oxygen. Hence, the encapsulation techniques are critical for the commercialization of perovskite solar cells for real-world applications. In this work, we systematically compared three encapsulation materials and fully evaluated the impact of encapsulation on the materials and device stability. We intentionally tested the encapsulated samples in accelerated aging conditions, such as immersing them in boiling water. These accelerated stressing can effectively distinguish the encapsulation quality in a short period. The resulted hero devices encapsulated with optimized techniques showed significantly improved stability, suggesting great potential for real applications.

Dimethyl Ferrocene-Induced Ambient-Processed High-Quality Films toward Efficient Perovskite Solar Cells for Industrial Application.

Metal halide perovskite solar cells (PSCs) have recently made significant progress with power conversion efficiencies (PCEs) boosted from 3.8% to a certified one over 26.1%, partially benefiting from the high-quality perovskite film enabled by the effective one-step spin-coating route. However, an extra antisolvent step with poor controllability and producibility is often involved in such a process, and some intrinsic defects are generated inevitably, especially in ambient atmospheric conditions, thus fundamentally limiting the commercialization of PSCs. Here, we introduce 1,1'dimethyl ferrocene into methylammonium lead halide precursor, which could not only recover the defects within perovskite film but also simplify the process without the extra antisolvent step. Accordingly, a dense and uniform perovskite film with large grains has been obtained under ambient conditions, which has much lower defect density, better stability against moisture penetration, and enhanced thermal tolerance than the control one, delivering a champion PCE of 16.92%. Current work sheds light on the simplified air-processed strategy for high-quality perovskite films, which might pave the way for exploring efficient and stable PSCs toward industrial applications.

Interfacial Property Tuning Enables Copper Electrodes in High-Performance n-i-p Perovskite Solar Cells.

Developing cost-effective metal electrodes is essential for reducing the overall cost of perovskite solar cells (PSCs). Although copper is highly conductive and economical, it is rarely used as a positive electrode in efficient n-i-p PSCs due to its unmatched Fermi level and low oxidation threshold. We report herein that modification for the inner surface of electrodes using mercaptopyridine-based molecules readily tunes the electronic and chemical properties of copper, which has been achieved by fine-tuning the substituents of mercaptopyridines. The systematic adjustment for the Fermi level and oxidation potential of copper facilitates interfacial hole extraction and enhances the oxidation resistance of copper electrodes, which enables pure copper electrodes to be used in high-performance n-i-p PSCs with different hole transport materials. The resulting PSCs with copper electrodes display excellent power conversion efficiency and long-term stability, even comparable to those of the gold electrodes, showing great potential in the manufacturing and commercialization of PSCs.

(Invited) Progress in Materials and Process for Sustainable Perovskite Solar Cells

All solid-state solar cells based on organometal trihalide perovskite absorbers have already achieved distinguished power conversion efficiency (PCE) to over 25% and further improvements are expected up to 27%. Now, the research on perovskite solar cells (PSCs) has been moving toward commercialization. To facilitate commercialization of these great solar cells, some technical issues such as long-term stability, large scale fabrication process, and Pb-related hazardous materials need to be solved. Also, flexible perovskite solar cell using plastic substrate can be used in niche applications such as portable electrical chargers, electronic textiles, and large-scale industrial roofing.This talk is dealing with our recent efforts to facilitate commercialization of perovskite solar cells. For examples, we introduce a recycling technology of perovskite solar cells, which covers the regeneration process of Pb contained perovskite layer as well as recycling process of Au electrodes and transparent conducting oxide glass. Also, simple fabrication technologies for realizing large scale perovskite module are introduced and recent effort for achieving high efficiency module is going to be presented. Finally, recent interesting results regarding ultra flexible perovskite cells will be discussed.