The Study Of Composite Photoanodes And New Dyes Based DSSC Devices

Dye-sensitized solar cell?DSSC?has attracted intensive interest as one of the most promising alternative photovoltaic devices for future clean renewable energy production,due to their facile fabrication,low manufacturing cost,environmental friendliness and moderate light to electrical energy conversion efficiency.Photoanode and dye,as the working electrode and the main light sensitizer,are the heart components to determine the power conversion efficiency?PCE?.In this thesis,focusing on photoanode and new synthesized dyes in our group,we prepared and studied the DSSC devices.The main contents are as follows:?1?In situ preparation of dual-layer TiO₂ photoanodes.Firstly,utilizing electrospray?E-spray?,different microstructures of TiO₂ films were prepared by varying nozzle to substrate distance,followed by scanning electron microscopy study and mono photoanode application in DSSCs.By adjusting the E-spray time,the best thickness of photoanode was obtained.Then dual-layer films as well as their corresponding DSSC devices were fabricated and studied.The device working principles were investigated by uv–vis spectra,diffuse reflectance spectra,electrochemical impedance spectroscopy and incident photon-to-current conversion efficiency spectra.It was found that owing to the ability to achieve the balance between high dye loading and low charge transfer resistance,the device with H2.5/2.0 showed the highest power conversion efficiency?PCE?of 8.96%.?2?Firstly,based on four new dyes of pure organic,DSSC devices were fabricated and characterized.Then,with one of the four material,CBPTZ2,device optimization was conducted.By adjusting the thickness of photoanode,dye-soaking temperature and electrolyte composition,the best PEC of 9.84% was obtained.?3?Graphene quangum dots?GQDs?were introduced in the preparation of TiO₂ by E-spray deposition,followed by DSSC device study.It was found that GQDs were able to significantly improve the electron transport in the photoanode.Device with high efficiency of 8.09% was obtained,with optimized thickness.