A low-cost and high-efficient heat dissipation film from 3D synergistic enhancement by infrared emission, sunlight reflection and heat conduction

Radiative cooling offers a promising energy-free thermal management approach for electronic devices. However, the practical application of conventional radiative cooling materials is limited by their low thermal conductivity, leading to heat accumulation from internal sources. In this work, a low-cost and high-thermal-conductivity radiative cooling film (HTCRCF) was developed by introducing three-dimensional (3D) co -doped fillers that consist of BN platelets and spherical Al 2 O 3 particles into a polydimethylsiloxane (PDMS) matrix. In contrast to conventional low-thermal-conductivity materials, the 3D synergistic strategy simultaneously enhances infrared emission, sunlight reflection, and heat conduction at a low cost. The HTCRCF achieves a high solar reflectivity of 93%, an infrared emissivity of 0.95 and a thermal conductivity 2.7 times higher than that of the matrix. Outdoor tests demonstrate radiative cooling performance of 7.8 °C under direct midday sunlight and 2.4 °C at night. Moreover, HTCRCF demonstrates excellent radiative cooling performance higher than the ambient temperature, lowering substrate temperatures by a remarkable 29.7 °C under sunlight and 17.3 °C in indoor environments. This work provides a scalable solution for high-power electronic devices cooling and bridges the gap between radiative cooling efficiency and thermal management requirements in real-world applications.