Doped silicon nanoparticles for enhanced charge transportation in organic-inorganic hybrid solar cells

Abstract

In this work, we have added p-type and n-type Si nanoparticles (NPs) obtained from cryomilling, in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) organic photovoltaic cell at different weight ratios and their effect on organic-inorganic hybrid solar cell device parameters has been evaluated. It is observed that the addition of p-type nanoparticles tailors the energy band alignment at the P3HT/NP interface which provides efficient charge carrier transport enhancing the photo-conversion efficiency by more than 21%. Enhancement is reflected by an improvement in short-circuit current by ∼35% with respect to reference P3HT:PC61BM device without Si NPs. However, for n-type NPs where the optimum cascading band alignment does not occur, only 10% improvement in photo-conversion efficiency is observed. This work provides insight into how the performance of organic solar cells can be tailored by size factor as well as byenergy level tuning of the added nanoparticles.