[60]PCBM single crystals: remarkably enhanced band-like charge transport, broadband UV-visible-NIR photo-responsivity and improved long-term air-stability. Issue 20 (14th May 2018)

• Record Type: Journal Article
• Authors: Zhao, Xiaoming; Liu, Tianjun; Hou, Xueyan; Liu, Zilu; Shi, Wenda; Dennis, T. John S.
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 20(2018)
• Page Start: 5489
• Page End: 5496
• Publication Date: 2018-05-14
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8tc00867a
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : [60]PCBM single crystals were prepared to understand their intrinsic photo-responsivity, stability, and charge transport properties. Abstract : We report the charge transport mechanism, long-term stability and UV-visible-NIR photo-responsivity of single crystals of [60]PCBM (phenyl-C61 -butyric acid methyl ester) – a dominant acceptor material in organic photovoltaics. Despite [60]PCBM's paramount role in such devices, its intrinsic properties are largely unknown because it forms highly disordered solution-processed films, the electron transport mechanism remains ill-defined, and the long-term stability is poor – posing a major bottleneck for advancing cell efficiency and stability. We employed a liquid–liquid interfacial precipitation strategy to grow single crystals of [60]PCBM, which allowed us to experimentally elucidate its electron transport properties, long-term stability and photo-responsivity. Temperature-dependent mobility studies enabled us to reveal its charge transport mechanism. Promisingly, [60]PCBM single crystals were found to exhibit a more favorable band-like charge transport mechanism at room temperature and present electron mobility exceeding that of their thin-film counterparts by two orders of magnitude. Photodetectors based on single crystals show broadband photo-responsivity from the UV and visible to NIR regions. Long-term stability tests showed that the performance of devices based on single crystals remained 80% after 480-hour aging, whereas the performance of thin film devices dropped by over 80% under the same conditions. Our findings underscore single crystals as a key strategy to achieve breakthroughs in highly efficient and stable devices.