Influence of Surface Functional Groups of ZnO Nanorods on the Performance of Cellulose Paper-Based Flexible Triboelectric Nanogenerator

We report on the fabrication of zinc oxide (ZnO) nanorod-based flexible, cost-effective single electrode triboelectric nanogenerator (STENG) on cellulose paper platform. In particular, the influence of surface functional groups of ZnO nanorods on the STENG output has been investigated. The STENG has been designed with chemically grown ZnO nanorod-coated paper as active triboelectric layer and Teflon/Aluminum as counter triboelectric layer/electrode. It has been found that post-annealing of nanorods at 125 degrees C improves the output voltage by twice compared to the pristine nanorods and delivers an output power of similar to 0.2 mu W/cm(2). With annealing up to 125 degrees C, the optimal removal of the chemisorbed water from the defect sites of ZnO surface increases the intrinsic carrier concentration leading to maximum charge transfer and hence higher triboelectric output. On the other hand, a higher extent of oxygen accumulation from air at 150 degrees C lowers the intrinsic carrier concentration resulting in the reduced output. It has been proposed that the competition between the events like water removal and oxygen accumulation under different annealing temperatures can influence the STENG output largely. Finally, the optimized STENG has been demonstrated to work as wearable biomechanical sensors operating through bio-mechanical stimuli.

Automated summary

This study reports on the fabrication of a flexible and cost-effective single electrode triboelectric nanogenerator (STENG) based on zinc oxide (ZnO) nanorods on a cellulose paper platform. The influence of surface functional groups of ZnO nanorods on the STENG output was investigated. It was found that post-annealing of nanorods improves the output voltage, while oxygen accumulation reduces the output. The optimized STENG was demonstrated to work as a wearable biomechanical sensor.