High performance transient organic solar cells on biodegradable polyvinyl alcohol composite substrates

Abstract

Physically transient electronics represent an emerging class of technology which can disappear in a controlled manner when triggered by stimuli. Transient power supply devices are essential components in meeting the power demands of transient systems. Here we report on the first demonstration of transient organic solar cells (OSCs) fabricated on polyvinyl alcohol (PVA) composite substrates. PVA is employed as a substrate material because of its high transparency, good water solubility and versatility in chemical and physical properties by appropriate choice of composition. The dissolution and transparency of PVA substrates can be programmed by addition of sucrose or gelatin at different ratios, which further define the photovoltaic performance and transiency behavior of the transient OSCs. Based on the poly(3-hexylthiophene):[6,6]-phenyl-C₆₁-butyric acid methyl ester (P3HT:PC₆₁BM) system, a power conversion efficiency up to 2.05% is obtained for OSCs fabricated on a PVA/sucrose substrate with a ratio of 2 : 1 (PS2), which is comparable to that of the reference devices on glass substrates (2.37%). Once triggered by deionized water, the devices disconnect within only 10 s exposure to stimuli. When using a PVA/gelatin composite with a composition of 2 : 1 (PG2) as substrate, the disintegration is significantly prolonged. The devices can maintain their integrity even after an hour of exposure, however, in forms of individual particles. Efficient and easy fabrication of transient OSCs on the PVA-based substrates is expected to open the door for transient organic photovoltaic technology.