Application of Wide Band Gap Semiconductors to Increase Photocurrent in a Protein Based Photovoltaic Device

摘要

Reaction centers (RCs) from natural photosynthetic cells are photoactive proteins, which generate electron-hole pairs in presence of light. In a new approach presented in this work, a solution of suspended RCs with mediators has been applied as the electrolyte to build electrochemical based photovoltaic (PV) devices. In this approach, the mediators transfer charges from the RCs to the electrodes (indirect charge transfer). Various metallic and wide bandgap semiconducting materials, including Carbon, Au, Indium Tin Oxide (ITO), SnO_2, WO3, have been tested as the electrodes. Among all WO_3, which is a semiconductor, have shown the largest photocurrent density with an amount of ～5.1 μA/cm~2. The results show that the material of the electrode can affect the rates of the reactions in the cell. Choosing an appropriate material for the electrode, the charge transfer from the mediators to the electrode would be rectified to achieve a large photocurrent.