Modelling of Charge Carrier Mobility Effect on Organic Bulk Heterojunction Solar Cells

Abstract

In this article, we did some simulations of organic bulk heterojunction solar cells according to the Koster model. The study shows that bimolecular recombination and a temperature- and field dependence generation mechanism of free charges incorporation. The charge carrier is one of most important factors that have influence on the devices’ power conversion efficiency (PCE), because the charge carrier mobility have effect on dissociation and transport processes, which are governing the PCE. The balance of the electron and hole mobilities are not necessary to maintain the optimal efficiency, the performance of solar cell will enhance when each of mobilities increases. For solar cell with a Schottky barrier between the semiconductor and the metal electrode, the efficiency therefore always increases with the mobility. Our calculation results also show that the short-circuit quantum efficiency is determined by the competition between exciton dissociation and recombination. The high carrier mobility leads to a very narrow space charge layers near the contact interface.

Keywords:

• Bulk heterojunction
• charge carrier mobility
• electron
• hole

Acknowledgments

The authors are grateful to Major Project of Science and Technology Development Plan of Jilin Provincial Science and Technology Department (Grant No.20090545), Scientific Frontier and Interdiscipline Innovative Projects of Jilin University (Grant No.200903082), National Natural Science Foundation of China (Grant No.61006013).