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Modulation of donor alkyl terminal chains with shifting branching point leads to optimized morphology and efficient all-small-molecule organic solar cells
摘要： Terminal group modification is one of the most influential factors for small molecular donors compared with their polymer counterparts, resulting in an opportunity to optimize the morphology of all-small-molecule organic solar cells (ASM-OSCs). In this manuscript, we report three novel small molecular donors with branching points at the 1-, 2-, and 3-positions in alkyl terminal chains, called BSCl-C1, BSCl-C2 and BSCl-C3, respectively. Using IDIC-4Cl as acceptor, the subtle branching position shift achieves a dramatic disparity in photovoltaic parameters, as indicated by the short circuit current (Jsc) changing from 4.90 mA cm?2 to 20.1 mA cm?2 to 14.2 mA cm?2 and the fill factor varying from 33.9% to 71.3% to 67.0% for BSCl-C1, BSCl-C2, and BSCl-C3, respectively. The best device performance of 12.4% is obtained by the BSCl-C2:IDIC-4Cl system, which not only ranks among the top values reported to date, but also exhibits low energy loss in systems that use IDIC as acceptors. The notable device performance based on BSCl-C2 is attributed to the optimized phase morphology caused by the strong molecular crystallinity and suitable intermolecular interaction with IDIC-4Cl. These results demonstrate that suitably tuning the branching position of terminal groups could promote the high performance of ASM-OSCs.
关键词： branching point,phase morphology,crystallinity,intermolecular interaction,all-small-molecule
更新于2025-09-23 15:21:01
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Ultrafast Hole Transfer and Carrier Transport Controlled by Nanoscale-Phase Morphology in Nonfullerene Organic Solar Cells
摘要： Nonfullerene acceptors (NFAs) have attracted great attention in high-efficiency organic solar cells (OSCs). While the effect of molecular properties including structures and energetics on charge transfer have been extensively investigated, the effect of macroscopic phase properties is yet to be revealed. Here we have performed a correlation study of the nanoscale phase morphology on photoexcited hole transfer (HT) process and photovoltaic performance, by combing ultrafast spectroscopy with high temporal resolution and photo-induced force microscopy (PiFM) with high spatial and chemical resolution. In PM6/IT-4F, we observe a biphasic HT behavior with a minor ultrafast (< 100 fs) interfacial process and a major diffusion mediated HT process till ~ 100 ps, which depends on phase segregation strongly. Because of the interplay between charge transfer and transport, a compromised domain size of 20 ~ 30 nm for NFAs shows best performance. This study highlights the critical role of phase morphology in high-efficiency OSCs.
关键词： photo-induced force microscopy,phase morphology,ultrafast spectroscopy,organic solar cells,hole transfer,Nonfullerene acceptors
更新于2025-09-19 17:13:59
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Ti3+-doped TiO2(B)/anatase spheres preparedusingthioglycolic acid towards super photocatalysis performance
摘要： A high efficiency photocatalyst, TiO2(B)/anatase spheres consisted of nanosheets were prepared. Thioglycolic acid (TGA) was added into the precursor to control the hydrolysis process of titanium source (TiCl3), which is a key to adjust the microstructure of products. The results indicated that TGA-modified samples revealed enhanced photocatalysis performance compared with the one without TGA. The photocatalysis performance of TGA-modified sample is about 15 times high compared with commercial P25. This is ascribed to mixed crystal phase and lattice distortion which resulted in more activity sites (e.g. Ti3+ and oxygen defects). The loading of Au nanoparticles in different ways confirms that rich Ti3+-oxygen vacancies on the surface of samples caused super photocatalytic performance.
关键词： Phase,Morphology,Photocatalysis,TiO2
更新于2025-09-10 09:29:36