Photophysics of organic materials and photovoltaic effect are discussed, with an overall understanding of the “organic solar cell relevant theory” that is consistent with the experiments....[ Read more ]

Photophysics of organic materials and photovoltaic effect are discussed, with an overall understanding of the “organic solar cell relevant theory” that is consistent with the experiments.

Single layer photovoltaic cells (ITO/PPA/ A1 and lTO/MEH-PPV/A1 ) have been made and investigated. Quite different absorption spectra are given by the two type cells, leading to different photoresponse respectively. The I-V characteristics for the two type devices with various thicknesses are measured and analyzed. It was found that the thickness of the films greatly effects the performance of the devices. In addition, the surface morphologies are shown using AFM to help for improving the film fabrication.

Double layer photovoltaic cells ( ITO/MEH-PPV/A1Q3/A1) have also been made with various MEH-PPV film thicknesses but keeping the A1Q3 film thickness unchanged. The photoresponse spectra are almost “in phase ” with the absorption except that the thinner one shows a clear red shift. On the other hand, comparing with the single layer devices, they are more efficient with two orders higher of photocurrent magnitude and also higher open circuit voltage.

It is concluded that the double layer devices show obvious advantages over the single ones. For future work, more architectures and materials are valuable for investigation, in order to achieve high efficient organic photovoltaic devices.