Thiazolothiazole-containing conjugated polymers for indoor organic photovoltaic cells

Organic solar cells (OSCs) have attracted considerable attention in the last few decades due to their unique properties, including lightweight, flexibility, and manufacturing costs. Moreover, OSCs exhibit high performance under ambient light conditions revealing potential applications of these devices in low power electronics and Internet of Things (IoT) systems. In this work, we synthesized and characterized two novel conjugated polymers comprising thiazolothiazole, benzothiadiazole and thiophene alternating blocks with different thioalkyl substituents. Polymer P1 with 2-ethylhexylthio side chains provided power conversion efficiencies of ca. 5.0% on 4.5 cm2 area OSCs fabricated using slot-die coating technique under ambient conditions. Furthermore, the assembled P1-based module delivered the power output of 45.5 μW under 400 lx indoor illumination sufficient to power wireless air temperature sensor, thus demonstrating the potential of our devices for practical indoor applications.