Inverted Organic Photovoltaic Cells having Stacked Structure of a Bulk Heterojunction Layer and a Donor Layer

The evaporative spray deposition using ultradilute solution (ESDUS) technique enables layer-by-layer deposition of polymer semiconductors. In the present study we prepared inverted organic photovoltaic cells with stacked layer structure of mixture film of a polythiophene and a fullerene derivative (i-layer) and polythiophene film (p-layer) by ESDUS. The i-p stacked structure brought about significant improvement in the device performance probably due to the electron blocking at the polythiophene film.