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In ACS applied materials & interfaces ; h5-index 147.0

In this work, photothermal materials are integrated with a temperature-sensitive hydrogel and structural color for visually detecting solar intensity. Inspired by the functional performance of beetles, the photothermal layer is constructed by depositing candle soot on a film of Cu nanoparticles, while the temperature-sensitive colored hydrogel is fabricated by self-assembling colloidal photonic crystals on poly(N-isopropylacrylamide) (PNiPAM). The deposition of candle soot not only improves the photothermal performance but also leads to a superhydrophobic surface with a self-cleaning function. The photothermal layer absorbs sunlight and converts it into heat, which is then transferred to the hydrogel. The structural color of the hydrogel changes due to the heat-induced volume shrinkage. As the solar intensity increases from 0.62 to 1.27 kW/m2, the structural color conspicuously changes from red to orange, yellow, green, cyan, and blue, with reflection peaks shifting from 640 to 460 nm accordingly. The color change is highly apparent, which can be easily observed by the naked eye, suggesting that the solar intensity can be easily detected by reading out the structural color. This power-free and self-cleaning solar sensor can work for a long period without maintenance, which is suitable for a wide application prospect, such as smart home and agriculture.

Xiong Meiyu, Sheng Yuhang, Di Yunsong, Xing Fangjian, Yu Liyan, Zhang Jinlei, Zhou Weiping, Liu Cihui, Dong Lifeng, Gan Zhixing


hydrogels, photonic crystals, photothermal effect, solar detector, structural color