Rare-earth compounds have been emerging as promising materials for infrared radiative cooling in electronic devices, owing to their exceptional thermal stability, tunable optical properties, and unique phonon-mediated thermal emission within the atmospheric transparency window. This study investigates the infrared (IR) emission behavior of various rare-earth (REPO 4 ) phosphates, focusing on the influence of rare earth ion species, structural characteristics, and temperature effects on their spectral properties. Three distinct morphologies of REPO 4 (RE = Y, Ce, Sm) nanopowders were successfully synthesized via a precipitation method using citric acid as metal ion complexing agent. It is discovered that spherical YPO 4 particles enhance lateral IR scattering and promote IR absorption. Additionally, the IR emissivities of all three samples are significantly influenced by oxygen vacancies and the band gap. Oxygen vacancies increase the free carrier concentration, which enhances IR emissivity, while a reduction in the band gap lowers the energy barrier for electron transitions, facilitating IR absorption. The synergistic effects of these factors yield a remarkable broadband IR emissivity of up to 0.966 for YPO 4 . The composite film created by embedding REPO 4 into PDMS achieved a cooling effect of up to 8.1 °C at an input power of 8 W (power density of 5000 W/m 2 ), demonstrating its effectiveness for cooling electronic devices. These findings indicate the great potential of rare-earth phosphates in advancing sustainable radiative cooling technologies for next-generation electronics.
The COVID-19 pandemic and airborne particulate matter (PM) pollution have posed a great threat to human health. Personal protective face masks have become an indispensable protective equipment in our daily lives. However, wearing conventional face masks for a long time cause swelter and discomfort on the face. Introducing thermal comfort into personal protective face masks becomes desirable. Herein, face masks that show excellent filtration performance and radiative heat dissipation effect are successfully designed and prepared by electrospining Nylon-6 (PA) nanofibers onto polyethylene (PE) meltblown nonwovens. The resultant PE/PA nonwovens have high PM filtration efficiency (>99%) with a low pressure drop (<100 Pa). Moreover, taking the advantage of the property of PE, the designed face mask posses high mid-infrared (mid-IR) transmittance and brings about high radiative cooling power, resulting in effective heat dissipation performance. This face mask design may provides new insights into the development of thermal comfort materials for personal protection.
Jiangtao Li,Yunjia Xue,Xueying Zhang,Fan Zhang,Wenhao Hu,Jiachen Liu
The SiC-ZrO 2 coating was prepared on the surface of aluminosilicate ceramic fiber fabric (ASFF) to enhance the radiation heat dissipation. However, the Si-sol in the SiC-ZrO 2 coating caused the fiber to adhere together at high temperatures. The brittle fracture of the ASFF led to a deterioration in its temperature resistance. In this paper, an Al 2 O 3 interface was prepared on the surface of ASFF by spraying alumina precursor. The Al 2 O 3 interface prepared by 3.0 wt% alumina precursor was uniformly covered on the fiber surface. The flexibility of ASFF/Al 2 O 3 /SiC-ZrO 2 was maintained after static oxidation at 1300 °C for 1 h. The tensile strength of ASFF/Al 2 O 3 /SiC-ZrO 2 at 1200 °C were increased from 5 to 7 MPa to 21.35 ± 2.58 MPa. The Al 2 O 3 interface not only limited the direct contact between Si-gel and fiber, but also reacted with Si-gel to produce mullite at high temperature. The problem of fiber adhesion caused by Si-sol in ASFF matrix was solved. Additionally, the SiC-ZrO 2 coating reduced the surface temperature of ASFF rom 1700 °C–1300 °C. Combining the radiation performance of SiC-ZrO 2 coating and the isolation effect of the Al 2 O 3 interface, ASFF/Al 2 O 3 /SiC-ZrO 2 was able to operate continuously for 300 s under the 1700 °C butane-oxygen flame heating condition.
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