Improved charge separation and transport efficiency in poly(3- hexylthiophene)-TiO2 nanorod bulk heterojunction solar cells

In this article, we have fabricated photovoltaic devices based on the poly(3-hexylthiophene)-TiO2 nanorod bulk heterojunction. The microscopic mechanisms of charge separation and charge transport in the poly(3-hexylthiophene)-TiO2 nanorod nanocomposites have been investigated by photoluminescence quenching, time-resolved photoluminescence spectroscopy, and time-of-flight mobility measurements. Charge separation and transport efficiency can be improved by adding an adequate amount of TiO 2 nanorods in polymer. In addition, the device performance can be further enhanced by thermal annealing or removal of insulating surfactant in the hybrid, giving an optimized device performance of a short circuit current density of 2.62 mA cm-2, an open circuit voltage of 0.69 V, a fill factor of 0.63 under simulated A.M. 1.5 illumination (100 mW cm-2). The corresponding power conversion efficiency under 1 sun is about 1.14%. © The Royal Society of Chemistry.