Current density improvement of colloidal PbS quantum dot solar cells by adding NaCl in ZnO electron transport layer

Abstract

In this work, the effect of adding sodium chloride (NaCl) in zinc oxide (ZnO) electron transport layer (ETL) on the photovoltaic performance of lead sulfide (PbS) quantum dot (QD) solar cells is investigated. To elucidate that, PbS QD solar cells with pristine ZnO and NaCl passivated ZnO (ZnO–NaCl) as ETLs are fabricated, respectively. The current density–voltage (J–V)​ measurements are performed. The results show a considerable improvement in the current density of the device with ZnO–NaClas ETL, thus boosting the power conversion efficiency (PCE) from 7.278% to 9.149%. It is demonstrated that NaCl treatment benefits surface defects and series resistance (Rs) reduction in ZnO ETL, enhancing the carrier transport performance of the device. The strategy of adding NaCl in ZnO ETL provides a promising way for pushing solar cell performance to a high level.