Nb2O5 as a new electron transport layer for double junction polymer solar cells

Abstract

Nb₂O₅ as a new electron transport layer (ETL) was used for double junction polymer solar cells. The Nb₂O₅ ETL was prepared by spin coating a Nb₂O₅ sol–gel solution onto the active layer of the optical front subcell. The double junction devices using Nb₂O₅ ETL exhibit an open circuit voltage (V_oc) of 1.30 V, which is close to the sum of the s of the individual subcells. The current density–voltage (J–V) simulation showed that the double junction device performance using Nb₂O₅ as ETL could be significantly increased by reducing the series resistance (R_se) and matching the current densities of the individual subcells.