Enhanced performance of solution‐processed carbon nanotube transparent electrodes in foldable perovskite solar cells through vertical separation of binders by using eco‐friendly parylene substrate

Abstract The successful utilization of an eco‐friendly and biocompatible parylene‐C substrate for high‐performance solution‐processed double‐walled carbon nanotube (CNT) electrode‐based perovskite solar cells (PSCs) was demonstrated. Through the use of a novel inversion transfer technique, vertical separation of the binders from the CNTs was induced, rendering a stronger p‐doping effect and thereby a higher conductivity of the CNTs. The resulting foldable devices exhibited a power conversion efficiency of 18.11%, which is the highest reported among CNT transparent electrode‐based PSCs to date, and withstood more than 10,000 folding cycles at a radius of 0.5 mm, demonstrating unprecedented mechanical stability. Furthermore, solar modules were fabricated using entirely laser scribing processes to assess the potential of the solution‐processable nanocarbon electrode. Notably, this is the only one to be processed entirely by the laser scribing process and to be biocompatible as well as eco‐friendly among the previously reported nonindium tin oxide‐based perovskite solar modules.