Laser-Induced Graphene Arrays for Dual-Function Electromagnetic Interference Shielding and Photothermal Conversion

With the rapid growth of 5G communication and wearable electronics, developing multifunctional materials has become a research hotspot. Traditional single-function materials are inadequate to meet the needs of integration and lightweight design in complex applications. In this study, the optimization of electromagnetic interference (EMI) shielding and photothermal conversion was achieved in a laser-induced graphene (LIG) system. Patterned LIG arrays with various period were fabricated on polyimide (PI) films using a CO2 laser. A sandwich-structured device was subsequently built, comprising a patterned LIG array as the top layer, PI as the middle layer, and a LIG continuous film (LIGCF) as the bottom layer. The results indicate that a decrease of the array period leads to a significant increase in both conductivity and EMI shielding performance. Specifically, the L-60 array achieves the electrical conductivity of 1985 S/m and the EMI shielding effectiveness of 35.57 dB. With the addition of a LIGCF as the bottom reflective layer, the sandwich structure further improves EMI shielding effectiveness to 49.48 dB, demonstrating an enhancement toward efficient EMI shielding. For photothermal performance, small periods of LIG arrays have higher steady-state temperature, whereas the sandwich structure exhibits a lower steady-state temperature comparing to the single-layer array. It reveals the regulation mechanism of the period on EMI shielding and photothermal conversion performance.