Charge transport properties of low temperature solution processable poly(3-hexylthiophene)/surfaee modified TiO2 bulk heterojunction systems

Abstract

The solution processable poly(3-hexylthiophene)(P3HT)/TiO 2-nanorod hybrid material for solar cells has been successfully demonstrated. A critical issue for using hybrid heterojunction concept is the interface properties which affect the exciton separation efficiency and bi-carrier transport. To improve the interface properties, we replace the insulating surfactant on TiO2 nanorod surface with a more conductive oligomer, carboxylate terminated 3-hexylthiophene (P3HT-COOH). The enhancement of exciton separation efficiency due to better organic-inorganic interfacial compatibility can be obtained. The electron mobility for transporting in the TiO2 network is improved. A power conversion efficiency has been increased 3 times by using this new hybrid material without optimization as compared with the hybrid without P3HT-COOH modification.