Tetrakis (N-phenothiazine) spirobifluorene-based hole-transporting material towards high photovoltage perovskite photovoltaics for driving electrochromic devices

• Published in: Dyes and pigments 2021-04, Vol.188, p.109164, Article 109164
• Main Authors: Liu, You, Liu, Fang, Wang, Jungan, Huang, Hongyan, Yan, Suhao, Gao, Song, Wang, Lin, Huang, Wei, Qin, Tianshi
• Format: Article
• Language: English
• Subjects: High photovoltage; Hole-transporting material; Photovoltaic electrochromic; Wide-bandgap photovoltaics
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2021.109164

Wide-bandgap photovoltaics (WBPV) could not only provide electrical energy by photoelectronic conversion of the invisible part of the solar spectrum, but also usually had the unique advantage of high open circuit voltage (Voc). In this work, we reported a novel HTM based on tetrakis (N-phenothiazine) Spirobifluorene (Spiro-PT), its HOMO energy level could be well matched with MAPbBr3 perovskite HOMO energy level. This HTM could effectively suppress nonradiative recombination, which leads to an increase in the photovoltage of WBPV to more than 1.41 V. As a result, the n-i-p mesoscopic structured WBPV achieved a champion PCE of 7.36% as well as excellent operational stability exhibiting 91% of initial efficiency after 500 h continuous illumination without encapsulation. Based on the high Voc of the MAPbBr3/Spiro-PT device, the photovoltaic electrochromic device showed a response speed (the average coloring time was 40 s and the bleaching time was 272 s) and high average visible light transmittance contrast (about 37% in 450–780 nm), the corresponding electrochromic device with maximum dynamic contrast up to 46% at 600 nm between bleached and colored states. This WBPV-powered electrochromic system could provide a pathway towards stand-alone smart window technique for future energy-saving buildings. [Display omitted] •The undoped hole-transporting material (HTM) Spiro-PT was synthesized by one-step Buchwald-Hartwig reaction.•The HOMO energy level of perovskite and Spiro-PT had a better band alignment.•The wide-bandgap photovoltaics (WBPV) performance based on Spiro-PT as HTL was superior to that based on Spiro-OMETAD as HTL.•The champion open circuit voltage of the WBPV devices could reach 1.41V.•The maximum dynamic contrast of electrochromic devices driven by WBPV at 600 nm is as high as 46%.