Metal-electrode-free inverted organic photovoltaics using electrospray-deposited PEDOT:PSS and spin-coated HAT-CN exciton blocking layer

Abstract Poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) films were fabricated using an electrospray deposition (ESD) method. The ESD PEDOT:PSS films exhibited higher PSS content on the surface than spin-coated PEDOT:PSS films, which results in a higher work function. Based on this result, metal-electrode-free inverted organic photovoltaics (OPVs) were fabricated. The ESD PEDOT:PSS was used as the top electrode on the poly(3-hexythiophene-2,5-diyl) (P3HT):[6,6]-phenyl C61 butyric acid methyl ester (PCBM) light-absorbing layer. The power conversion efficiency (PCE) of OPVs was significantly increased with the 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile layer. The improved PCE would be attributed to the suppression of exciton quenching at the P3HT:PCBM and PEDOT:PSS interface.