Biocompatible polydopamine based triboelectric nanogenerator for humidity sensing

Humidity sensing is a critical parameter for various applications, ranging from environmental monitoring to healthcare and food packaging. Traditional humidity sensors show respectable sensitivity but suffer from a shorter battery life span and slow response time. However, the triboelectric nanogenerator (TENG) technology has emerged as a promising alternative for humidity sensing, offering superior performance and compatibility with various substrates. TENGs can convert mechanical energy into electrical energy without needing an external power source. This unique feature makes TENG a promising platform for self-powered environmental sensors. In this context, synthesizing biocompatible polydopamine (PDA) material and using it for a humidity sensing layer represents a significant step toward advancing next-generation sensors. This study presents a biocompatible PDA-incorporated 3D-printed TENG for self-powered humidity sensing. The output voltage and current of the multi-unit TENG is measured to be 90 V and 2.4 μA, respectively. The TENG demonstrates a sensitivity of 1.55 V/10 RH% over the relative humidity range from 25 % to 92 %. As humidity increases, the resistance of the humidity sensor decreases, resulting in a reduction in electrical voltage output. TENG has potential applications in various fields and could be a promising candidate for next-generation humidity sensors.