Shenghua Lin,Ling Ai,Jing Zhang,Tongle Bu,Hongjiang Li,Fuzhi Huang,Jun Zhang,Yuehui Lu,Weijie Song
Silver ants forage at extremely high environmental temperatures, the hairs of which play a crucial role in reducing the body temperature via enhanced optical reflection and radiative heat dissipation as a passive daytime radiative cooler. Inspired by the hierarchical feature structure of the hairs, we fabricated the flexible photonic architectures (FPA) on polydimethylsiloxane (PDMS). With some modification to the feature structure, the FPA-PDMS exhibited not only a large emittance in the mid-infrared spectral range , comparable with that of state-of-the-art thermal emitters , but also the record-high transmittance and haze in the visible and near-infrared range, which would be particularly appealing to photovoltaic devices for maximizing sunlight absorption and minimizing parasitic heat. The ease of application of the FPA-PDMS was demonstrated in both emerging perovskite and mature commercial crystalline silicon solar cells , where the FPA-PDMS was electrostatically attached to their glass superstrates or covers and the improvements in photovoltaic characteristics as a result of enhanced light harvesting were confirmed through laboratory measurements. Though the synergetic effects of the improved transparency and heat radiation brought by the FPA-PDMS need to be characterized outdoors in the future, these findings pave the way for suppressing optical and thermal losses simultaneously in opto-electric-thermal coupled devices through learning sophistically evolved photonic architectures from nature.
Wanchun Wu,Shenghua Lin,Mingming Wei,Jinhua Huang,Hua Xu,Yuehui Lu,Weijie Song
Saharan silver ants can inhabit one of the hottest areas, the Sahara Desert, which benefits from their thermoregulatory functionality, thanks to a sophisticated photonic structure of hairs. Mimicking the photonic structure, we fabricated the flexible hair-like photonic structures on polydimethylsiloxane (PDMS). Attaching them to glass bottles for a proof-of-concept demonstration, the considerably enhanced optical reflection was observed as well as the slightly improved mid-infrared emission. These extraordinary properties enabled the temperature of the glass bottles to be reduced by around 5.6 °C in the hot daytime and keep relatively warm in the cold nighttime. On the basis of optical and thermal properties of the silver ants-inspired photonic structures, potential applications could be further found in wearable devices and personal thermal management.