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Beneficial effects of potassium iodide incorporation on grain boundaries and interfaces of perovskite solar cells
摘要： Grain boundaries and interfacial impurities are the main factors that limit the further development of polycrystalline perovskite solar cells because their existence severely deteriorates the device performance. In order to optimize the efficiency of perovskite solar cells, it is essential to eliminate these defects. In the present work, potassium iodide (KI) is incorporated into the perovskite absorber. KI incorporation improves the crystallinity of the perovskite, increases the grain size, and decreases the contact potential distribution at the grain boundary, which are verified by X-ray diffraction, scanning electronic microscopy and Kelvin probe force microscopy. Besides, the activation energy of the recombination, estimated from the temperature dependent current–voltage of perovskite solar cells, is larger than the bandgap calculated from the temperature coefficient. These suggest that KI incorporation effectively passivates the grain boundaries and interfacial defects. As a result, charge trapping in the absorber as well as the bimolecular and trap-assisted recombination of the device are significantly suppressed. Consequently, the open circuit voltage and fill factor of the incorporated devices are greatly improved, enabling an optimized power conversion efficiency of 19.5%, in comparison with that of 17.3% for the control one. Our work provides an effective strategy of defect passivation in perovskite solar cells by KI incorporation and clarifies the mechanism of the performance optimization of KI incorporated devices.
关键词： potassium iodide,perovskite solar cells,defect passivation,grain boundaries,power conversion efficiency
更新于2025-09-11 14:15:04
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Highly Efficient Planar Perovskite Solar Cells via Acid-assisted Surface Passivation
摘要： Low-temperature solution-processed SnO2-based perovskite solar cells (PSCs) have achieved great progresses recently, but it still suffers from a critical drawback due to the defects at SnO2/perovskite interface. Herein, we report a facile acetic acid post-treatment strategy to effectively passivate the surface defects. Under the optimal concentration of acetic acid modification, the average power conversion efficiency (PCE) of the planar-type triple cation PSCs is greatly increased from 18.57% to 20.33%. The champion device shows a PCE of 20.56%. In addition, the universality of this passivation strategy is double confirmed by achieving an enhanced average PCE from 19.52% to 21.64% for sequential method deposited dual cation PSCs, with a leading PCE of 21.95%. Our work demonstrates an effective passivation strategy for SnO2-based planar-type PSCs, which will benefit the development of high-efficient PSCs.
关键词： defect passivation,interface,perovskite solar cells,tin oxide
更新于2025-09-11 14:15:04
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Interfacial Modification and Defect Passivation by Crosslinking Interlayer for Efficient and Stable CuSCN-Based Perovskite Solar Cell
摘要： Study of the inorganic hole-transport layer (HTL) in perovskite solar cell (PSC) is gathering attention due to the drawback of conventional PSC design, where the organic HTL with salt dopants majorly participates in the degradation mechanisms. On the other hand, inorganic HTL secures better stability, while it offers difficulties in the deposition and interfacial control to realize high-performing devices. In this study, we demonstrate polydimethylsiloxane (PDMS) as an ideal polymeric interlayer which prevents the interfacial degradation, and improves both photovoltaic performance and stability of CuSCN-based PSC by its crosslinking behavior. Surprisingly, the PDMS polymers are identified to form chemical bonds with perovskite and CuSCN, as shown by Raman spectroscopy. This novel crosslinking interlayer of PDMS enhances the hole-transporting property at the interface and passivates the interfacial defects, realizing the PSC with high power-conversion efficiency over 19%. Furthermore, the utilization of PDMS interlayer greatly improves the stability of solar cells against both humidity and heat, by mitigating the interfacial defects and interdiffusion. The PDMS-interlayered PSCs retained over 90% of the initial efficiencies, both after 1000 h under ambient condition (unencapsulated) and after 500 h under 85°C/85% relative humidity (encapsulated).
关键词： Crosslinking Interlayer,Inorganic Hole-Transport Layer,Defect Passivation,Stability,Perovskite Solar Cell
更新于2025-09-11 14:15:04
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Reversible PL Tuning by Defect Passivation via Laser Irradiation on Aged Monolayer MoS2
摘要： Atomically thin (1L) MoS2 emerged as a direct band gap semiconductor with potential optical applications. The photoluminescence (PL) of 1L-MoS2 degrades due to aging related defect formation. The passivation of these defects leads to substantial improvement in optical properties. Here we report the enhancement of PL on aged 1L-MoS2 by laser treatment. Using photoluminescence and Raman spectroscopy in a controlled gas environment, we show the enhancement is associated with efficient adsorption of oxygen on existing sulfur vacancies preceded by removal of adsorbates from the sample’s surface. Oxygen adsorption depletes negative charges, resulting in suppression of trions and improved neutral exciton recombination. The result is a 6-8 fold increase in PL emission. The laser treatment in this work does not cause any measurable damage to the sample as verified by Raman spectroscopy, which is important for practical applications. Surprisingly, the observed PL enhancement is reversible by both vacuum and ultrafast femtosecond excitation. While the former approach allows switching a designed micro pattern on the sample ON and OFF, the latte provides a controllable mean for accurate PL tuning, which is highly desirable for optoelectronic and gas sensing applications.
关键词： Raman,Exciton,Laser Annealing,Oxygen,Photoluminescence,Reversible Defect passivation,MoS2
更新于2025-09-11 14:15:04
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Minimizing non-radiative recombination losses in perovskite solar cells
摘要： Photovoltaic solar cells based on metal-halide perovskites have gained considerable attention over the past decade because of their potentially low production cost, earth-abundant raw materials, ease of fabrication and ever-increasing power-conversion efficiencies of up to 25.2%. This type of solar cells offers the promise of generating electricity at a more competitive unit price than traditional fossil fuels by 2035. Nevertheless, the best research-cell efficiencies are still below the theoretical limit defined by the Shockley–Queisser theory, owing to the presence of non-radiative recombination losses. In this Review, we analyse the predominant pathways that contribute to non-radiative recombination losses in perovskite solar cells and evaluate their impact on device performance. We then discuss how non-radiative recombination losses can be estimated through reliable characterization techniques and highlight some notable advances in mitigating these losses, which hint at pathways towards defect-free perovskite solar cells. Finally, we outline directions for future work that will push the efficiency of perovskite solar cells towards the radiative limit.
关键词： defect passivation,photovoltaic,perovskite solar cells,Shockley–Queisser theory,non-radiative recombination losses
更新于2025-09-11 14:15:04
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Additive Engineering for Efficient and Stable Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) have reached a certified 25.2% efficiency in 2019 due to their high absorption coefficient, high carrier mobility, long diffusion length, and tunable direct bandgap. However, due to the nature of solution processing and rapid crystal growth of perovskite thin films, a variety of defects can form as a result of the precursor compositions and processing conditions. The use of additives can affect perovskite crystallization and film formation, defect passivation in the bulk and/or at the surface, as well as influence the interface tuning of structure and energetics. Here, recent progress in additive engineering during perovskite film formation is discussed according to the following common categories: Lewis acid (e.g., metal cations, fullerene derivatives), Lewis base based on the donor type (e.g., O-donor, S-donor, and N-donor), ammonium salts, low-dimensional perovskites, and ionic liquid. Various additive-assisted strategies for interface optimization are then summarized; additives include modifiers to improve electron- and hole-transport layers as well as those to modify perovskite surface properties. Finally, an outlook is provided on research trends with respect to additive engineering in PSC development.
关键词： perovskite solar cells,additives,stability,Lewis acid,defect passivation
更新于2025-09-11 14:15:04
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Simultaneous Contact and Grain‐Boundary Passivation in Planar Perovskite Solar Cells Using SnO <sub/>2</sub> ‐KCl Composite Electron Transport Layer
摘要： The performance of perovskite solar cells is sensitive to detrimental defects, which are prone to accumulate at the interfaces and grain boundaries of bulk perovskite films. Defect passivation at each region will lead to reduced trap density and thus less nonradiative recombination loss. However, it is challenging to passivate defects at both the grain boundaries and the bottom charge transport layer/perovskite interface, mainly due to the solvent incompatibility and complexity in perovskite formation. Here SnO2-KCl composite electron transport layer (ETL) is utilized in planar perovskite solar cells to simultaneously passivate the defects at the ETL/perovskite interface and the grain boundaries of perovskite film. The K and Cl ions at the ETL/perovskite interface passivate the ETL/perovskite contact. Meanwhile, K ions from the ETL can diffuse through the perovskite film and passivate the grain boundaries. An enhancement of open-circuit voltage from 1.077 to 1.137 V and a corresponding power conversion efficiency increasing from 20.2% to 22.2% are achieved for the devices using SnO2-KCl composite ETL. The composite ETL strategy reported herein provides an avenue for defect passivation to further increase the efficiency of perovskite solar cells.
关键词： electron transport layer,perovskite solar cells,defect passivation
更新于2025-09-11 14:15:04