Charge‐Transfer Cocrystal via a Persistent Radical Cation Acceptor for Efficient Solar‐Thermal Conversion
Jieqiong Xu, Qian Chen, Shengkai Li, Jiachao Shen, Phouphien Keoingthong, Liang Zhang, Zhiwei Yin, Xinqi Cai, Zhuo Chen, Weihong Tan
Abstract
Abstract Designing organic charge‐transfer (CT) cocrystals for efficient solar‐thermal conversion is a long‐sought goal but remains challenging. Here we construct a unique CT cocrystal by using a persistent 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation (ABTS +. ) as the electron acceptor. The strong persistency and electron affinity of ABTS +. endow a high degree of electron delocalization between ABTS +. and the 3,3′,5,5′‐tetramethylbenzidine donor. Together with the intrinsic long‐wavelength absorption of ABTS +. , the synthesized cocrystal can effectively capture the full solar spectrum and show distinguished photothermal efficiency. Such a cocrystal is further used for solar‐driven interfacial evaporation, and a high evaporation rate of 1.407 kg m −2 h −1 and a remarkable solar‐to‐vapor efficiency of 97.0 % have been achieved upon 1 sun irradiation. This work indicates the enormous prospects for charge transfer‐based functional materials through rational radical cation engineering.