Electrical and optical properties of composite PEDOT: PSS-based thin films with NiO nanoparticles

Abstract

Due to the combination of low cost materials deposition and device fabrication methods as well as competitive efficiency compared to the other Si solar cell architectures, the hybrid organic-silicon solar cells have attracted attention of the scientific community. It has recently been demonstrated that spin-coated poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (hereafter PEDOT:PSS) on a silicon wafer is a promising material due to its good optical and electrical properties. However, degradation caused by atmospheric exposure and relatively poor passivation properties limits implementation of PEDOT:PSS- silicon devices. Functionalization of PEDOT:PSS by inorganic nanoparticles might provide a possible solution as was shown for TiO_2 and SnO_2 nanoparticles. In this contribution, we present our results on spincoated PEDOT:PSS thin-films with NiO nanoparticles. We show that PEDOT:PSS mixed with Triton X-100 and dimethyl sulfoxide (DMSO) or ethylene glycol (EG) form a homogenous film and passivates the Si surface with charge carrier lifetimes of 300-400 ms with good reproducibility. Time-resolved measurements revealed continuous degradation of the passivation properties in air, however saturation of the degradation at approximately 150 ms was observed in N_2 atmosphere. The influence of the NiO nanoparticles on the optical properties of PEDOT:PSS is negligible, whereas the surface passivation properties are worsened due probably to the formation of large size agglomerates exceeding thickness of PEDOT:PSS film.