Selenium-fullerene heterojunction solar cells and techniques for fabrication thereof are provided. In one aspect, a method of forming a solar cell includes: forming a front contact on a substrate; depositing an n-type semiconducting layer on the front contact, wherein the n-type semiconducting layer comprises a fullerene or fullerene derivative; forming a p-type chalcogen absorber layer on the n-type semiconducting layer; depositing a high workfunction material onto the p-type chalcogen absorber layer, wherein the high workfunction material has a workfunction of greater than about 5.2 electron volts; and forming a back contact on the high workfunction material. Solar cells and other methods for formation thereof are also provided.