Asymmetric band engineering for superior multifunctional energy conversion

Efficient conversion of environmental signals into electrical energy is essential for self-powered devices and sensing technologies. Traditional designs often rely on single-function mechanisms, leading to inefficiencies and scalability issues. In this work, we introduce an asymmetric band engineering strategy that integrates multiple energy conversion pathways within a single composite nanofiber membrane (SCNFM). By exploiting electrode work function differences, the asymmetric energy-level configuration between Al/SCNFM and Cu/SCNFM enhances charge transport and couples thermally induced, humidity-driven, and piezoelectric processes for efficient energy conversion. The SCNFM demonstrates a temperature range of 25–210 °C, humidity detection from 30 to 90% RH, and pressure sensing from 0.5 to 3 N, with stable outputs under varying conditions. Under coupled temperature and humidity stimuli, the device exhibits a 21% voltage enhancement at 70 °C, demonstrating a clear synergistic effect. This design simultaneously converts temperature, humidity, and pressure stimuli into complementary DC and AC signals without external bias, offering a scalable framework for multi-stimulus energy harvesting and self-powered sensing in applications such as flexible electronic skins and wearable health monitors.