RESUMO
Photothermal regulation concerning solar harvesting and repelling has recently attracted significant interest due to the fast-growing research focus in the areas of solar heating for evaporation, photocatalysis, motion, and electricity generation, as well as passive cooling for cooling textiles and smart buildings. The parallel development of photothermal regulation strategies through both material and system designs has further improved the overall solar utilization efficiency for heating/cooling. In this review, we will review the latest progress in photothermal regulation, including solar heating and passive cooling, and their manipulating strategies. The underlying mechanisms and criteria of highly efficient photothermal regulation in terms of optical absorption/reflection, thermal conversion, transfer, and emission properties corresponding to the extensive catalog of nanostructured materials are discussed. The rational material and structural designs with spectral selectivity for improving the photothermal regulation performance are then highlighted. We finally present the recent significant developments of applications of photothermal regulation in clean energy and environmental areas and give a brief perspective on the current challenges and future development of controlled solar energy utilization.
RESUMO
Given health threat by global warming and increased energy consumption in regulating body temperature, it is an urgent need to construct smart temperature-regulating materials. Herein, a novel fiber-spinning asymmetric chemical assembly (FACA) method is proposed to construct nanofiber materials with asymmetric photothermal properties. The silver nanowires (AgNWs) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) with opposite thermal radiation are assembled on reduced graphene oxide (rGO) film, imparting AgNW/rGO/PVDF-HFP film with Janus structure that can realize the AgNWs side consistently keeps temperature of ca. 11 °C lower than the side of PVDF-HFP nanofiber regardless of the irradiation directions under 1 sun, suggesting the adjustable photothermal regulation. Such photothermally selective hybrid nanofiber film provides great potential as fabrics to achieve all-weather smart clothes, promoting controllable and comprehensive utilization of solar energy.
RESUMO
Organic-inorganic halide perovskite nanocrystals (PNCs) have shown great advantages in recent years due to their tunable emission wavelengths, narrow full-width at half-maximum (FWHM) and high photoluminescence quantum yield (PLQY). However, PNCs still face the challenges of poor stability, difficulty in processing and generation of heavy metal wastes; therefore, it is necessary to develop a green synthetic method to prepare PNCs. Here, we present for the first time a facile fiber spinning chemistry (FSC) method for the rapid preparation of organic-inorganic halide PAN/MAPbX3 (MA = CH3NH3, X = Cl, Br and I) nanofiber films at room temperature. The FSC process utilizes spinning fibers as the reactor, and polymer solidification and the in situ generation of PNCs occur simultaneously with solvent evaporation during the spinning process. This method not only achieves a continuous large-scale preparation of PNC/polymer nanofiber films but also avoids the generation of heavy metal waste. The organic-inorganic halide PAN/MAPbX3 nanofiber films fabricated by FSC demonstrated tunable emission in the range of 464-612 nm and PLQY of up to 58%, and the fluorescence intensity remained essentially unchanged after 90 days of storage in the atmospheric environment. Interestingly, we successfully prepared high-efficiency white light-emitting diodes (WLEDs) and wide color gamut liquid crystal displays (LCDs) with a color gamut of 116.1% using PAN/MAPbBr3 nanofiber films as fluorescence conversion materials. This study provides a novel way to construct high-performance PNC/polymer fiber composites on a large scale.