Bandgap science for organic solar cells

Abstract

pn-control techniques, by impurity doping, both for single and co-deposited films consisting of two kinds of organic semiconductors have been established. A series of fundamental junctions such as Schottky junctions, pn-homojunctions, p⁺, n⁺/metal ohmic junctions, n⁺p⁺-ohmic homojunctions, and tandem cells showing 2.4% efficiency have been successfully fabricated in co-deposited organic semiconductor films by impurity doping alone. 3^rd co-evaporant molecule induced phase separation/crystallization of co-deposited films, which drastically enhances the magnitude of photocurrent density, was demonstrated.