Nanostructured metal oxide/conjugated polymer hybrid solar cells by low temperature solution processes

In this article, we have proposed a nanostructured photovoltaic device based on the ZnO nanostructures/poly(3-hexylthiophene)(P3HT):TiO2 nanorod hybrid by solution processes at low temperature. An array of ZnO nanorods with a larger size of ∼50 nm in diameter and ∼180 nm in length are grown to provide direct pathways for efficient charge collection. TiO2 nanorods with a size of ∼5 nm in diameter and ∼20–30 nm in length are incorporated into polymers to facilitate charge separation and transport by providing an increased interfacial area and a more effective transport pathway. The device performance with the inclusion of TiO2 nanorods exhibits a seven times increase in the short circuit current with respect to that without TiO2 nanorods. The device performance can be further enhanced after completely removing the residual surfactant on the TiO2 nanorods using the ligand exchange method, giving a short circuit current density of 2.67 mA cm−2 and a power conversion efficiency of 0.59% under Air Mass 1.5 (100 mW cm−2) illumination.