The Study On The Polymer Solar Cells

Solar cells are devices transferring the sun-light to electrical energy, which is one of the main objects as the renewable energy all over the world. In this paper, the factors that influence the performance of organic solar cells based on polymer were studied in order to improve performance of devices. The main works are as follows:1. Improvement of the performance of the interface: The MEH-PPV was chosen as the donor and the PCBM as the acceptor, A standard device with structure of ITO/PEDOT: PSS/MEH-PPV:PCBM/AL was fabricated. A buffer layer between the organic active layer and the metal cathode was added to study its influence on the performance of devices. The results showed that the BCP layer not only improved the open-voltage, but also enhanced the short-current, while the LiF layer also increased the open-voltage, but deduced the short-current.2. Improvement of the absorbency of the organic active layer: The effect of the Rubrene on the device performance was studied when it was added into the MEH-PPV: PCBM layer as doping dye. The aim of doping the Rubrene was to improve the absorbency of the organic active layer in the visible light range. The results indicated that the doping do not improve the performance of the devices, but deduced the performance which is contrary to our expectancy. Further analysis concluded that it may be the organic small-molecule which exert negative effect, but it is also worthy of investigating to improve the performance of the solar cells by doping.3. Broaden the spectral coverage: The absorption of MEH-PPV: PCBM blend film is mainly in the range of 400 to 550nm. There are also much wavelength range not fully used in the visible range. In order to improve the spectra match, CuPc which is complementary in absorption spectra to that of the MEH-PPV (450- 800nm) was doped into the active layer. The results indicated that the absorption of the device with the CuPc was broadened indeed, which is in accord with our expectancy. However both the open-voltage and short-current were decreased, which is similar to the effect of the Rubrene.