Effect of diamine treatment on the conversion efficiency of PbSe colloidal quantum dot solar cells

Polymer-free photovoltaic devices were fabricated via a solution process using PbSe colloidal quantum dots (QDs) and an organic semiconductor (tetrabenzoporphyrin, BP) that can be prepared in situ from a soluble precursor. The device structure was ITO/PEDOT/BP:QD/QD/Al, where the BP:QD and QD layers correspond to a bulk heterojunction and a buffer layer, respectively. The buffer layer was treated with ethylenediamine (EDA) to crosslink the QDs. As a result, the energy conversion efficiency of the EDA-treated device was superior to that of an untreated device, mainly due to an increase in the short-circuit current density.