A 12% Efficient Silicon/PEDOT:PSS Heterojunction Solar Cell Fabricated at < 100 degrees C

Solar cells based on a heterojunction between crystalline silicon and the organic polymer PEDOT:PSS were fabricated at temperatures < 100 degrees C by spin coating. The Si/PEDOT interface blocks electrons in n-type silicon from moving to the anode and functions as a low-temperature alternative to diffused p-n junctions. The device takes advantage of the light absorption and transport properties of silicon and combines it with the simplicity of fabrication afforded by organics. Reverse recovery measurements were used to analyze the electron-blocking effectiveness of the heterojunction. The data show that current in the device is primarily due to holes injected from the anode into the silicon. At AM1.5, Si/PEDOT heterojunction solar cells achieve power conversion efficiency of 11.7%, which is among the highest reported values for this class of devices.