High performance silicon-organic hybrid solar cells via improving conductivity of PEDOT:PSS with reduced graphene oxide

The optical and electrical properties of PEDOT:PSS organic layer play a very important role in determining the power conversion efficiency (PCE) of Si-organic hybrid solar cells (HSCs). In the present study, properties of PEDOT:PSS thin films with reduced graphene oxide (rGO) and their impacts on the performances of the resultant Si-organic HSCs have been systematically investigated. The electrical conductivity of PEDOT:PSS improved 35% when rGO was added to PEDOT:PSS, and the fabricated HSCs with 2 mg/m1 rGO addition yielded an PCE of 11.95% with ajs, of 31.94 mAcm(-2), a Voc of 579 mV and a FF of 0.648. However, excess rGO would deteriorate the solar cells performances and it might create additional defects and prevent carriers being collected. The Raman spectroscopy, sheet resistance and EQE analyses with rGO suggested that the interaction between the conductive rGO flakes and the aromatic PEDOT most probably not only provide additional charge transport pathways in hole transport layer to improve carrier mobility leading to a higher carrier collection efficiency, but also suppress the electron recombination at the junction interface. In addition, the rGO serve as an antireflection coating to reduce the reflectance of PEDOT:PSS thin film leading to further enhanced performances of solar cells. (C) 2017 Elsevier B.V. All rights reserved.