Over 16% efficiency organic/nanostructured Si heterojunction solar cells with a p-doped organic small molecule layer

Abstract

Organic/nanostructured Si hybrid solar cells have achieved high power conversion efficiency (PCE) and short-circuit current density ( J SC ), due to the excellent light harvesting ability of nanostructured Si. However, the separation of carriers is mainly affected by the low work function of PH1000-type PEDOT:PSS, resulting in poor open circuit voltage ( V OC ). In this work, an efficient and stable MoO 3 -doped copper phthalocyanine-3,4′,4″,4‴-tetra-sulfonated acid tetra sodium salt (TS-CuPc) organic small molecule film was introduced between the heterojunction interfaces. The photogenerated carrier separation is promoted by the enhanced built-in potential ( V bi ) owing to the high work function of TS-CuPc:MoO 3 , which also suppresses the carrier recombination at the surface of nanostructured Si. As a result, for PEDOT:PSS/nanostructured Si photovoltaic devices, the PCE was greatly improved from 14.15% to 16.09%. The excellent charge separation properties and interface passivation effect enable efficient devices to demonstrate the vast potential of this new type of interlayer in photovoltaic applications. • The p-type doping increases the work function of TS-CuPc films. • The interlayer substantially improves charge separation at the Si/organic interface. • The device efficiency is as high as 16.09%, and V OC and FF are improved overall.