Thermally Conductive Radiative Cooling Films for Thermal Management of Flexible Devices

Radiative cooling provides a solution for managing heat in flexible electronic devices, particularly those that undergo complex deformations. However, most current radiative cooling materials are inadequate for cooling heat-producing devices due to their selective infrared emission and low thermal conductivity. Herein, a thermally conductive radiative cooling (TCRC) film with enhanced mechanical properties is proposed by incorporating hexagonal boron nitride ( h -BN) nanoplates and alumina (Al 2 O 3 ) nanospheres within a polydimethylsiloxane (PDMS) matrix. h -BN nanoplates are primarily responsible for high solar reflection and thermal conduction, while Al 2 O 3 nanospheres are expected to improve the infrared emission and film hardness. This advanced film achieves a solar reflectivity of 84.2% and a broadband infrared emissivity of 98.3%, even at a relatively low loading level, and features a 2-fold increase in thermal conductivity compared to the matrix. Thanks to the combined effects of efficient solar reflection, broadband infrared emission, and improved thermal conduction, the TCRC film demonstrates excellent above-ambient cooling performance under direct sunlight (∼13.7 °C) and indoor environment (∼5.9 °C). Besides, the film exhibits superior abrasion resistance, hydrophobicity, flame retardancy, and UV resistance. This work establishes a versatile and effective thermal management solution for flexible devices.