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Improved efficiency and photo-stability of methylamine-free perovskite solar cells via cadmium doping
摘要： Although perovskite solar cells containing methylamine cation can show high power conversion efficiency, stability is a concern. Here, methylamine-free perovskite material CsxFA1–xPbI3 was synthesized by a one-step method. In addition, we incorporated smaller cadmium ions into mixed perovskite lattice to partially replace Pb ions to address the excessive internal strain in perovskite structure. We have found that the introduction of Cd can improve the crystallinity and the charge carrier lifetime of perovskite films. Consequently, a power conversion efficiency as high as 20.59% was achieved. More importantly, the devices retained 94% of their initial efficiency under 1200 h of continuous illumination.
关键词： cadmium doping,methylamine-free,lattice strain,photo-stability
更新于2025-09-23 15:19:57
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Intrinsic Photo-degradation and Mechanism of Polymer Solar Cells: The crucial role of Non-fullerene Acceptor
摘要： The performances of polymer solar cells (PSCs) based on non-fullerene acceptors (NFAs) have improved remarkably in recent years, but such devices are insufficiently stable for practical applications. Here, we investigated the effects of NFAs on PSC long-term stability. We found that high performance PBDB-T:ITIC solar cells exhibit much lower stability than PTB7:PC71BM devices in the 1 sun light-soaking test; when compared with their initial performances, the performance of PTB7:PCBM-based solar cells remains above 60% for over 4000 h, whereas that of PBDB-T:ITIC-based devices is reduced to one fifth after 1000 h. We demonstrated that the ITIC-based PSCs exhibit poor photo-stability because ITIC at the interface of the ZnO/active film is readily decomposed by a photocatalytic reaction; this poor stability arises because the vinyl group of ITIC is chemically more vulnerable than the stable aromatic units in the organic active materials. The decomposition of ITIC results in the degradation of the electron transport properties of the active materials located close to ZnO, which leads to severe burn-in degradation and reduced FF and VOC under illumination. It is thus highly important to develop intrinsically stable organic materials composed of chemically stable building blocks in order to realize stable and high efficiency PSCs.
关键词： polymer solar cells,photocatalytic reaction,non-fullerene acceptors,photo-stability,ITIC
更新于2025-09-11 14:15:04
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Highly photo-stable CsPbI3 perovskite quantum dots via thiol ligand exchange and their polymer film application
摘要： Highly photo-stable CsPbI3 perovskite quantum dots (PeQDs) were prepared using thiol as an exchanged ligand. Photoluminescence of CsPbI3 perovskite quantum dots can be maintained for a long time in UV via thiol ligand exchange. As an application, perovskite films were fabricated using the PeQDs and a cyclic olefin copolymer (COC). The thiol-treated PeQD films exhibited higher stability than the untreated films under irradiation with a blue light-emitting diode (LED).
关键词： thiol-capped CsPbI3 perovskite quantum dots,photo-stability,QD films,Ligand exchange
更新于2025-09-11 14:15:04
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Controlled synthesis of nanocrystalline Nb:SrTiO <sub/>3</sub> electron transport layers for robust interfaces and stable high photovoltaic energy conversion efficiency in perovskite halide solar cells
摘要： Perovskite halides are of great attraction as efficient light absorption materials for solid-state solar cells, but the stability and photovoltaic energy conversion efficiency of perovskite solar cells (PSCs) are still limited by the interface structures and defects between their light-absorbing perovskite halides and electron transport layers (ETLs). Here, we report the ultraviolet (UV) light-induced degradation mechanism at the interfaces between perovskite halide and conventional TiO2 ETL materials, and provide a solution to overcome this drawback. UV-induced degradation is shown to be attributed to the formation of oxygen vacancies formed at the perovskite halide-ETL interface under UV light illumination, where the oxygen atoms released at the interface accelerate the decomposition of perovskite halide by inducing chemical reactions. Meanwhile, nanocrystalline SrTiO3 (STO) ETLs are revealed to be tunable in enabling high performance in PSCs under UV light illumination. Indeed, tuning the electronic structure of STO ETLs by Nb doping, in combination with the controllable removal of SrO phases segregated on the Nb-doped STO ETL surfaces, is exhibited to enable robust interface stability and stable high photovoltaic energy conversion efficiency for PSCs. Furthermore, we demonstrate that STO-based PSCs have no hysteresis due to low defect concentrations at the perovskite halide-STO ETL interfaces.
关键词： oxygen vacancy formation,electron transfer layer,perovskite oxides,photo stability,Perovskite solar cells
更新于2025-09-11 14:15:04
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On the photo-oxidation of perylene bisimide dyes in alcoholic solutions
摘要： Irradiation with intense blue LED light of Lumogen orange 240 (1) in non-reactive solvents led to bleaching. The products of these photochemical reactions were not possible to determine. Contrarily, irradiation in ethanol or propanol led to red color shifts caused by the formation of the ethoxy or propoxy derivative of Lumogen orange 240, respectively. These new reaction products are only formed when both light and oxygen are present. A possible mechanism for these photo-oxidation reactions, the implication for the stability of perylene type of fluorescent dyes under LED lamp conditions and possible preparative applications are discussed.
关键词： Fluorescent compounds,Photo stability,Lumogen orange 240,Photo-oxidation,Photo substitution
更新于2025-09-04 15:30:14