The effects of hydrogen plasma treatment of ZnO electron transport layers on VOC of polymer solar cell

摘要

The effects of surface modification of ZnO ETL by H-plasma treatment on the performance of bulk heterojunction (BHJ) solar cells were systemically investigated. The open circuit voltage (V_OC) of devices was dramatically improved after H-plasma treatment. Both Kelvin probe force microscopy (KPFM) and ultraviolet photoelectron spectroscopy (UPS) measurements indicate that the improved V_OC is attributed to the reduced work function of ZnO caused by H-plasma treatment. After 2.5 min H-plasma treatment, the power conversion efficiency (PCE) of solar cells has been increased from 3.03% to 3.84% with a high V_OC of 0.670 V.