Materials with passive daytime radiative cooling (PDRC) have drawn more attention as a result of their potential for energy savings. We prepared SiO 2 -encapsulated ZnO@ZIF-8 (ZZS) particles and a radiative cooling coating containing ZZS particles. Owing to the polyhedron structure and the phonon-polarization resonance of ZZS particles, the ZZS fabric coating could reflect sunlight with 83% and radiate heat to outer space with 0.96. Compared with the ambient air, its average temperature decreased by 6.4 °C, and the human body under direct sunlight could avoid overheating 3.9 °C. In addition, the ZZS coated fabric after rubbing still had good PDRC and its average temperature increased by 1.38℃ higher than the original ZZS coated fabric. Owing to good PDRC property, hydrophobicity, mechanical properties and simple methods, the widespread usage of ZZS coated fabric for personal thermal management appears to be promising.
Lei Ding,YiFan Chen,Zibo Hua,Li Liu,Haixu Chen,Zhengxiang Zhong,Yunzhe Du,Yudong Huang
ZnO quantum dots@SiO2 (ZnO QDs@SiO2) was synthesized by a modified sol–gel method, and then added to polyvinyl alcohol (PVA) to form an ink-absorbing coating with ultraviolet shielding performance on poly(ethylene terephthalate) (PET) films. A layer of silica encapsulated on the surface of ZnO QDs not only reduces the photocatalytic activity significantly, but also prevents the agglomeration of ZnO QDs in aqueous solution. The UV-vis transmittance spectrum of the as-prepared ink-absorbing coating displayed excellent shielding performance in the ultraviolet region (<355 nm) and high transmittance in the visible region. Even when exposed to 30 W ultraviolet for 100 h, no obvious changes were observed in its UV-vis transmittance spectrum, showing long-term durability. Notably, the ink absorption of the ink-absorbing coating prepared using ZnO QDs@SiO2 is higher than that of the ink-absorbing coating prepared using commercially available silica. Therefore, a durable, highly transparent and ultraviolet shielded inkjet printing coating on PET can be prepared with ZnO QDs@SiO2 nanoparticles.
Achieving long-term stable lead halide perovskite nanocrystals (PNCs) in light-emitting devices remains a significant challenge because of their fast degradation upon exposure to light, moisture, and oxygen. Here, we report a facile one-pot strategy to realize the growth of crystalline ZnO/SiO 2 dual-layer encapsulation on CsPbBr 3 PNCs. The encapsulation provides the PNCs with robust surface passivation to withstand the harsh condition in hybrid light-emitting diodes (LEDs) with an on-chip packaging structure. The PNCs/ZnO/SiO 2 could preserve 100 % of their initial photoluminescence intensity after 500 h of continuous irradiation under a 9.6 W cm −2 blue laser. The fabricated green- and white-LEDs displayed constant light intensity at 80 % of their initial value with continuous driving at 10 mA for 500 h. We believe the excellent stability of the ZnO/SiO 2 encapsulated PNCs could strongly promote the development and application of perovskite-based light-emitting and other optoelectronic devices.
危险品化学品经营许可证（带存储）