Boron Subphthalocyanine Chloride as an Electron Acceptor for High‐Voltage Fullerene‐Free Organic Photovoltaics

Abstract

Abstract High‐efficiency fullerene‐free single‐heterojunction (SHJ) organic photovoltaic (OPV) cells consisting of tetracene (Tc) as a typical donor material and boron subphthalocyanine chloride (SubPc) as an acceptor material are reported. Cells containing SubPc as a direct replacement for C 60 exhibit an ∼60% improvement in open circuit voltage ( V oc ) achieving a maximum V oc of 1.24 V, which is amongst the highest values acheived to date for SHJ devices. This resulted in an overall improvement of ∼60% in power conversion efficiency from 1.8%, for Tc/C 60 cells, to 2.9% for Tc/SubPc. The OPV device results are complemented by soft X–ray photoelectron spectroscopy (PES) measurements of the interfacial energetics of both systems. The results demonstrate that SubPc shows considerable promise as an electron acceptor material for future cell designs.