plasma modification of carbon black for humidity-responsive devices

We present a novel approach for generating electricity from atmospheric moisture using a moist-electric generator (MEG) based on plasma-modified carbon black (CB). A 13.56 MHz radio frequency (RF) N₂ plasma was used to treat the CB surface. This process successfully introduced nitrogen-containing functional groups, significantly increasing the material's hydrophilicity and water adsorption capacity, as confirmed by FTIR and XPS analysis. The resulting MEG device, constructed from a simple paper-based substrate coated with the modified CB, demonstrated exceptional performance. It generated a stable open-circuit voltage (Voc) of 1.34 V and showed high sensitivity to changes in ambient humidity. The device's ability to dynamically respond to human respiratory cycles highlights its potential for self-powered applications, including breath monitoring sensors, wearable electronics, and adaptive smart materials. This work demonstrates a scalable and effective method for energy harvesting through plasma surface engineering.