High-Performance Organic Photothermal Material Based on Fusion of the Donor–Acceptor Structure for Water Evaporation and Thermoelectric Power Generation
Meng Zhao, Yunlong Zhu, Yuyu Pan, Ying Wang, Tao Xu, Xinpeng Zhao, Tao Jia, Zuolun Zhang, Zhijun Chen
Abstract
Recently, organic photothermal materials have shown great application potential for solar-driven water–electricity co-generation. However, their extended application is limited by low solar-heat conversion efficiency. This study designed a planarized donor–acceptor (D–A)-type organic photothermal material 5,18-dibutyl-5,18-dihydrodiquinoxaline[2,3-a:2′,3′-c]phenazine (DDHT) by fusing a strongly electron-donating arylamine unit and strongly electron-withdrawing quinoxalino[2,3-a]phenazine unit. The fused-ring D–A structure not only endowed the material with broad absorption spectra through low-energy intramolecular charge–transfer transition, but also allowed for intense intermolecular π–π interactions, which improve non-radiative transition probability and, correspondingly, the photothermal conversion efficiency (58.58% under laser irradiation at 655 nm). Under a solar intensity of 1 kW m–2, the water evaporation rate was 1.13 kg m–2 h–1 with a solar-to-vapor efficiency of 78.40% for the DDHT-based interfacial evaporation devices. Finally, a solar-driven steam and electricity co-generation device was prepared with the DDHT/wood composite as the solar-evaporator material, demonstrating electricity generation performances and excellent water purification capabilities. Our research found that fused-ring D–A structures are promising organic photothermal systems for efficient solar-heat conversion.