Multifunctional Daytime Radiative Cooling Devices with Simultaneous Light-Emitting and Radiative Cooling Functional Layers

Abstract

In this study, multifunctional light-emitting and passive radiative cooling (LEPC) materials and devices are designed by embedding chemically designed perovskite nanocrystals (NCs) into the radiative polymer layer. Lead halide perovskite NCs are chosen as the light-emitting material, owing to their high photon radiation rate and low phonon generation. To integrate the perovskite NCs into the radiative polymer layers, a surface passivation is achieved by coating the NCs with silica. The silica shell synergistically improves the chemical stability and cooling efficiency. Both outdoor experimental and simulation results demonstrate that the fabricated LEPC devices show better cooling performance than conventional cooling devices. The LEPC devices are easily patterned by utilizing pixelating, assembling, and simple cutting or drawing techniques with the LEPC materials. This study also demonstrates the potential applications of these materials as components of smart building systems, in smart window displays, or for anticounterfeiting cooling systems, thus proving the practicality of these multifunctional LEPC devices.

Cooling capacity evaluation of passive radiation cooling materials

“…The absorption power of 80 W/m 2 corresponds to that the radiation film has a transmittance of nearly 10%, so it is important to improve the sunlight reflection of the radiation film, otherwise the radiation film is difficult to obtain the cooling effect during the daytime. In this case, the temperature inside the test chamber was used as the environmental comparison temperature to evaluate the radiation cooling capacity in some articles [13][14][15][16]. As can be seen from figure 6 (b), for the case of 80 W/m 2 pad absorbing power, although the temperature at the center of the radiation film is greater than the external ambient temperature, it is still less than the temperature near the inner wall of the insulation chamber.…”

Colorful surfaces for radiative cooling

“…Another method to promote colored radiative cooling is integrating light emitting materials with thermal emission films. [77][78][79] Normally, the colored paints or pigments will inevitably result in solar heating. However, light-emitting materials, such as photoluminescent dyes, can partially convert the UV portion of solar irradiance into emitted light, hence slightly reducing the solar-heat conversion.…”

“…However, light-emitting materials, such as photoluminescent dyes, can partially convert the UV portion of solar irradiance into emitted light, hence slightly reducing the solar-heat conversion. With optimized structures, Jeon et al 78 reported colored emitters that can realize subambient cooling performance under 800 W∕m 2 solar illumination. Intriguingly, these photoluminescent films can produce vivid colors in dark environments at night [Figs.…”

Off-Grid Electrical Cell Lysis Microfluidic Device Utilizing Thermoelectricity and Thermal Radiation

“…The bilayer structure of polymers and metals is also widely used to maximize IR reflection and emission [57][58][59][60].…”

“…The Si-O-Si bond has good emissivity in the range of 8-13 µm [54][55][56]. The bilayer structure of polymers and metals is also widely used to maximize IR reflection and emission [57][58][59][60].…”