Effect of Energy States in Buffer Layer on Organic Solar Cells Output Performance

摘要

The energy states in cathode buffer layer induced by the metal cathode deposition were studied. The absorption spectra show the existence of energy states in cathode buffer layer, and the energy level of states can be estimated in a quantitative manner. The distribution of state energy levels in the cathode buffer layer is appropriated fof the electron transport from C_(60) to metal cathode. In addition, the Secondary Ion Mass Spectrometer (SIMS) showed the diffusion depth profile of Ag deposition on the bathocuproine (BCP) layer, indicating the relation between the efficiency of organic solar cells (OSCs) and the BCP thickness. As a result, the optimal BCP thickness plays an important role on the OSCs performance for avoiding C_(60) contact with Ag without affecting the electron collection from C_(60) to Ag.