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- Wan, Li, et al.
(författare)
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Sensitive near-infrared circularly polarized light detection via non-fullerene acceptor blends
- 2023
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Ingår i: Nature Photonics. - : NATURE PORTFOLIO. - 1749-4885 .- 1749-4893. ; 17:8, s. 649-655
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Tidskriftsartikel (refereegranskat)abstract
- Circularly polarized light (CPL) is widely used for various applications in sensing and imaging(1-3). An ongoing challenge is to realize high-quality CPL detection using chiral organic semiconductors, especially in the near-infrared (NIR) region(4). Chiral molecules tend to rely on twisted stereogenic moieties; however, conventional approaches to reduce the bandgap of organic semiconductors are based on the use of co-planar backbones that commonly lead to molecular symmetries preventing chirality. Here we report a widely applicable strategy to directly induce chiroptical activity in planar non-fullerene acceptors(5-7), which are widely used for high-performance organic photovoltaics and provide a wealth of opportunities to fill the spectral gap of CPL detection in the NIR regime. We demonstrate proof-of-concept circularly polarized organic photodiodes using chiroptically active non-fullerene acceptor blends, which exhibit strong circular dichroism and hence great sensitivity to CPL in the NIR region. Importantly, this strategy is found to be effective in a wide series of state-of-the-art non-fullerene acceptor families including ITIC5, o-IDTBR6 and Y6 analogues(7), which substantially broadens the range of materials applicable to NIR CPL detection.
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| 2. |
- Zhang, Tiankai, et al.
(författare)
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Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells
- 2022
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 377:6605, s. 495-501
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Tidskriftsartikel (refereegranskat)abstract
- Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2,7,7-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9-spirobifluorene (spiro-OMeTAD). Conventional doping of spiro-OMeTAD with hygroscopic lithium salts and volatile 4-tert-butylpyridine is a time-consuming process and also leads to poor device stability. We developed a new doping strategy for spiro-OMeTAD that avoids post-oxidation by using stable organic radicals as the dopant and ionic salts as the doping modulator (referred to as ion-modulated radical doping). We achieved PCEs of >25% and much-improved device stability under harsh conditions. The radicals provide hole polarons that instantly increase the conductivity and work function (WF), and ionic salts further modulate the WF by affecting the energetics of the hole polarons. This organic semiconductor doping strategy, which decouples conductivity and WF tunability, could inspire further optimization in other optoelectronic devices.
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