Room-Temperature Bolometric Response in Nitro-Boosted rGO

Graphene-based room-temperature bolometers with a high-temperature coefficient of resistance (TCR) and fast response times are emerging as promising technologies for thermal imaging, temperature sensing, and infrared (IR) detection. However, achieving high sensitivity in pristine graphene at ambient temperatures has been challenging due to weak electron-phonon interactions, which suppress the temperature dependence of the resistance. In this study, we propose a flexible microbolometer based on a reduced graphene oxide (rGO) and chitosan (CS) hybrid, which demonstrates a bolometric response at room temperature. The enhanced nitrogen functional groups in rGO, derived from chitosan treatment, act as defect centers that promote defect-assisted electron-phonon scattering (supercollision scattering), effectively overcoming the weak electron-phonon interaction at room temperature. Chitosan further enhances nitrogen functionality and imparts flexibility to the bolometer, leading to an improved TCR and durability. Our results show a maximum TCR of ∼3.1%/K, a current responsivity of ∼10.84 μA/W, and a thermal response time in the millisecond range for the nitro-boosted rGO-CS microbolometer near room temperature. This work presents a novel pathway for room-temperature bolometers, leveraging nitrogen-driven supercollision scattering in an rGO-CS hybrid.