Efficient inverted organic solar cells with a thin natural biomaterial l-Arginine as electron transport layer

Abstract

Proper interfacial modification is a necessary condition for high-performance organic solar cells (OSCs). In this work, l-Arginine (l-Arg) with the advantages of low price, friendly environment and widespread existence in natural was successfully introduced into inverted OSCs as electron transport layer (ETL). Compared to the devices without ETL (bare ITO), the open circuit voltage (VOC), short circuit current density (JSC) and power conversion efficiency (PCE) of the ITO/l-Arg /PTB7-Th:PC71BM/MoO3/Ag device was increased to 0.77 V, 17.25 mA·cm−2 and 9.00% from 0.36 V, 14.99 mA·cm−2, 1.90%, respectively. What’s more, the photovoltaic performance of the device with ZnO/l-Arg double ETL was further improved (PCE (9.31%)). The excellent PCE resulting from the improved work function and the increased interface conductivity, and thus more effective carrier extraction and collection. Furthermore, the lifetime of the device with ZnO/l-Arg double ETL was significantly increased in comparison with that of with pure ZnO ETL. The results indicated that double ETL formed by the introduction of l-Arg, which provides an efficient, low-cost, green and healthy method for the preparation of high-performance OSCs.