Fully Conjugated Covalent Porous Polymers for Highly Efficient Solar-Thermal Conversion.

Yang, Liuliu; Niu, Xianghong; Zhu, Shanshan; Hou, Yuxin; Xia, Hong; Yue, Huijuan; Luo, He-Kuan; Yang, Shuo-Wang et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

Solar-thermal water evaporation is a promising strategy for the clean water production. Developing photothermal conversion materials with high efficiency and stability is both urgent and challenging. Herein, we report two fully conjugated bipyranylidene-based microporous polymers (DP-CMP1 and DP-CMP2) for the first time, that feature broad light absorption, superior photothermal efficiency, and outstanding durability. Under the illumination of 660 nm laser with 100 mW cm<sup>-2</sup>, the temperature of DP-CMP1 drastically increased from 29.1 to 174.7 °C within 4 s. Furthermore, an interfacial heating evaporation system based on DP-CMP1 achieved high solar thermal water evaporation rates of 3.83 and 3.77 kg m<sup>-2</sup> h<sup>-1</sup> under 1 sun illumination for pure water and seawater, with excellent energy conversion efficiency of 97.5 and 96.6%, respectively. Multiple spectroscopic and theoretical investigations reveal DP-CMP1 is intrinsically an outstanding photothermal material owing to its small band gap, fast nonradiative combination rate, large nonadiabatic coupling value, and stronger electron-phonon coupling.