Synthesis of rGO/Pt(Nano Star) nanocomposite as hole transporting material in polymer solar cells

In the current work, reduced graphene oxide/Nano star platinum (rGO/Pt(NS)) nanocomposite is introduced as a novel hole transporting layer (HTL) to replace PEDOT:PSS in polymer solar cells (PSCs). The rGO/Pt(NS) nanocomposite was synthesized by in situ crystallization method, while formic acid and ethylene glycol vapor was used as the  reducing agent. Physical, chemical and electrochemical properties of the rGO/Pt(ns) nanocomposite was evaluated using different characterization techniques including FT-IR, XRD, TEM, EIS, CV and J-V tests. The rGO/Pt(NS) nanocomposite, appeared to have a desirable electrical conductivity  as a hole transporting material. Moreover, the prepared nanocomposite provided charge transfer resistance of 138Ω which was considerably lower than that obtained for PEDOT:PSS (208Ω). Also, by calculating the fermi level of rGO/Pt(NS) composite, it was found that the fermi level of rGO/Pt(ns) composite was in a more suitable place than the PEDOT:PSS. The photovoltaic performance of the rGO/Pt(NS) – based HTL PSCs was compared with those of the PEDOT:PSS – based HTL devices as standard PSCs. Results revealed that the rGO/Pt(NS) based PSCs can provide higher (about 13%) short circuit current (Jsc) and higher (18 %) power conversion efficiency (PCE).