The Investigation Of Co-sensitization And P-type Doping In Solid-state Dye-sensitized Solar Cells

Solar energy is a kind of safe,clean and abundant energy source.Solar cells are one of the important ways for the efficient use of solar energy.Solid-state dye-sensitized solar cells have advantages of green,high efficiency and stability,which are one of the most promising solar cells for practical applications.Organic dyes are generally used as light absorbers in solid-state dye-sensitized solar cells.Upon being excited under light illumination,photogenerated carriers would generate at once,then hole transport materials regenerate dyes and transport holes.The light-harvesting ability of the dyes will have a significant effect on the photocurrent density,which is influenced by thickness of the titanium dioxide films,light absorption range and molar absorption coefficient of the dyes if only use one kind of dye,thus the efficiency of devices could not be further improved dramatically.Co-sensitizing Ti O2 mesoporous films with two kinds of organic dyes with complementary light-absorbing spectra is a simple and effective method to broaden the light absorption range of the device.In this dissertation,HSQ4 and YD2-o-C8 were used as co-absorbers with LEG4 in the spiro-OMe TAD based devices.By optimizing the mixing ratio,the photocurrent density of the final device has been significantly improved compared to the device with a single dye,photoelectric conversion efficiency reached 5.9%and 5.8%,respectively.On the other hand,it is meaningful to research polymer P3 HT as hole-transport material in solid-state dye-sensitized solar cells due to its better optoelectronic performance than spiro-OMe TAD.In this paper,we use polymer P3 HT as hole-transport material in solid-state dye-sensitized solar cells,and F4 TCNQ is successfully introduced into the device as a p-type dopant.With mass doping ratio of 1%,the conductivity of material increased nearly by 20 times and the device efficiency reached 5.0%.This is the best efficiency of solution-processed polymer hole transport layer in solid-state dye-sensitized solar cells.