Introducing ZnMgO quantum dots to enhance optoelectrical characteristics of organic photovoltaics via light downconversion

Abstract

In this study, we developed organic photovoltaics (OPVs) with a photoactive layer based on the bulk heterojunction structure of the high-performance polymer PM6 and nonfullerene acceptor BTP-eC9. Zinc magnesium oxide (ZnMgO) quantum dots (QDs) were introduced into a zinc oxide sol–gel solution as the electron transport layer. The ZnMgO QDs absorb ultraviolet (UV) light and emit visible light (400–700 nm). The absorption area and external quantum efficiency of the fabricated OPV device were enhanced by converting UV light into visible light. Accordingly, the short-circuit current density and fill factor of the OPVs increased from 24.8 to 25.3 mA cm−2 and from 74.0 % to 74.8 %, respectively, and as a result, the power conversion efficiency of the OPVs increased from 15.1 % to 15.7 %. The absorption and photoluminescence emission and the particle size of the synthesized ZnMgO QDs were determined using UV–visible spectroscopy, photoluminescence spectroscopy, and high-resolution transmission electron microscopy.