Fabrication of OPVs by introducing a conductivity-enhanced hybrid buffer layer

Organic photovoltaic cells (OPVs) with a conductivity enhanced by doping with either dimethylsulfoxide (DMSO) or ethylene glycol (EG) were successfully fabricated to increase the photon harvesting property through localized surface plasmon resonance (LSPR) by adding Au nanoparticles to PH500, a hole collection layer, and effectively separating the generated charges. At Au nanoparticle and DMSO doping concentrations of 20 wt% and 1 wt%, respectively, the characteristics of the OPVs were optimized with a short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF) and estimated power conversion efficiency (PCE) of 8.0 mA/cm2, 0.595 V, 57.8% and 2.6%, respectively. Compared to the device with a buffer layer of conventional PEDOT:PSS, PCE was improved by ca. 85%. The series resistance (Rs), shunt resistance (Rsh), and hole mobility were 18 Ω cm2, 673 Ω cm2 and 4.2 cm2/Vs, respectively.