Robust organic radical cations with near-unity absorption across solar spectrum

作者：Shuai Zhang, Wenbin Huang, Yuxin Zhu, Jian Wang, Feng Cao, Qian Zhang, Engui Zhao, Zikai He · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-62581-5 · 被引用次数：11 · 研究领域：Photochemistry and Electron Transfer Studies、Atmospheric Ozone and Climate、Spectroscopy and Quantum Chemical Studies

Developing low-energy-gap materials for efficient photothermal conversion provides promising candidates for solar energy utilization. Herein, we explore the feasibility of employing robust organic radical cations as near-unity solar absorbers for practical seawater evaporation. Gram-scale organic radical cations are straightforwardly synthesized through single-electron oxidation. The open-shell structure and intervalence charge-transfer characteristics of radicals enable near-unity absorption of full solar spectral irradiance. Femtosecond transient absorption spectroscopy reveals that the intervalence charge-transfer electron relaxes non-radiatively in femtoseconds, with a rapid rate of 5.26 × 1012 s−1. Notably, the radical cations exhibit exceptional stability, attributed to para-position protection, spin delocalization, and frontier orbital inversion. By simply soaking cellulose paper, a highly efficient interfacial evaporation system is established. Under one sunlight irradiation, the system achieves a remarkable solar-to-vapor conversion efficiency of 97.2%. This work offers new perspectives on designing robust radical systems and developing efficient photothermal conversion materials. Open-shell organic radicals possess narrow energy gaps making them efficient solar absorbers. Here the authors synthesize robust triarylamine radicals enabling near unity absorption of the full solar spectrum for efficient photothermal applications.