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Acceptora??donora??acceptor type molecules for high performance organic photovoltaics a?? chemistry and mechanism
摘要： The study of organic photovoltaics (OPVs) has made great progress in the past decade, mainly attributed to the invention of new active layer materials. Among various types of active layer materials, molecules with A–D–A (acceptor–donor–acceptor) architecture have demonstrated much great success in recent years. Thus, in this review, we will focus on A–D–A molecules used in OPVs from the viewpoint of chemists. Notably, the chemical structure–property relationships of A–D–A molecules will be highlighted and the underlying reasons for their outstanding performance will be discussed. The device stability correlated to A–D–A molecules will also be commented on. Finally, an outlook and challenges for future OPV molecule design and device fabrication to achieve higher performance will be presented.
关键词： chemical structure–property relationships,device stability,organic photovoltaics,acceptor–donor–acceptor,molecule design
更新于2025-09-23 15:21:01
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Effect of fused triphenylamine core in star-shaped donor-??-acceptor molecules on their physicochemical properties and performance in bulk heterojunction organic solar cells
摘要： In this work, the synthesis of a novel star-shaped donor-acceptor molecule I with acridine-based core being a fused derivative of triphenylamine linked through π-conjugated terthiophene spacers and terminal hexyldicyanovinyl electron-withdrawing units is reported. Its physicochemical and photovoltaic properties were comprehensively studied and compared to those of molecule II being a structural analog but with a pristine propeller-like triphenylamine core. The novel molecule shows combination of the higher crystallinity, solubility and thermal stability. As compared to II, bulk heterojunction organic solar cells based on I as a donor and PC71BM as an acceptor showed the three times higher hole mobility, 50% larger external quantum efficiency, which resulted in up to twice higher power conversion efficiency reaching 6.14%. This work demonstrates that the triphenylamine core fused by p-tolylmethylene groups in the star-shaped donor acceptor molecules is a promising building block to design highly soluble and crystalline materials for organic optoelectronic devices.
关键词： oligothiophene,organic solar cell,dicyanovinyl,triphenylamine,donor-acceptor molecule
更新于2025-09-19 17:13:59
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Charge photogeneration and recombination in single-material organic solar cells and photodetectors based on conjugated star-shaped donor-acceptor oligomers
摘要： Single-material organic solar cells (SMOSC) are attracted by their simple structure and ease of fabrication so that they are virtually free from a number of drawbacks of heterojunction organic solar cells. However, the performance of SMOSC is still low, first of all because of poor understanding of losses on the way of energy conversion from light to electricity. In this work, we present solution-processed SMOSC based on star-shaped π-conjugated donor-acceptor oligomers with triphenylamine donor (N-Ph3) and alkyl- or phenyl dicyanovinyl acceptor (DCV-R) of general formulae N(Ph-nT-DCV-R)3, where nT stands for n-oligothiophene, and study charge photogeneration and recombination in them. SMOSC demonstrate small energy losses resulting in high open-circuit voltage of 1.08 – 1.19 V and the power conversion efficiency up to 1.22% under illumination intensity of 0.45 sun (1.13% under one sun) with the maximum external quantum efficiency up to 24% for N(Ph-2T-DCV-Ethyl)3, which are among the highest for SMOSC based on conjugated donor-acceptor small molecules or oligomers. It was found that monomolecular recombination dominates at the short-circuit condition and the maximum power point, but at the open-circuit condition the photoinduced charges recombine nearly bimolecularly. The bottleneck in the SMOSC performance was shown to be the field-assisted charge generation perfectly described by the Onsager model in the limit of weak electric fields. The results obtained suggest that intermolecular charge delocalization in conjugated donor-acceptor molecules would be beneficial for further progress in SMOSC.
关键词： conjugated molecule,charge recombination,donor-acceptor molecule,Onsager model,organic solar cell,charge generation
更新于2025-09-12 10:27:22