The Optimization Of Quantum Dots Sensitized Solar Cells Oxide Film And Sensitizer

As a third-generation solar cell,Quantum Dot sensitized Solar Cells?QDSSC?have received extensive attentions due to the low cost and high theoretical photoelectric conversion efficiency.Since the photoanode of QDSSC is the key to the cell,the optimization of the photoanode structure plays an important role in improving photoelectric conversion efficiency.Firstly,the structure and principle of QDSSCs have been introduced.Then the research on the semiconductor oxide film and quantum dot sensitizer were carried out,and the improvement of the cell performance by structural optimization has been investigated The main content of this thesis is:The first chapter introduces the background of QDSSCs,including the structure and principle of QDSSC,and the development of various components of photo-anode in QDSSC.The second chapter describes the preparation of Mn-doped quantum dot sensitized solar cells by a new chemical bath co-deposition method.After the doping of Mn elements into CdSe quantum dots?QDs?,the light absorption,photovoltaic characteristics,SEM morphology,EDS elemental and EIS impedance of QDSSC were analyzed and the reasons for the improvement in the performance were discussed.The light absorbing capability and photoelectron capturing ability of the working electrode are improved after the Mn doped into the CdSe QDs.The lifetime of electrons in the device is improved and the electron recombination rate at the interface is reduced due to the presence of Mn elements.Finally,the photoelectric conversion efficiency of Mn-doped QDSSC is increased and the device efficiency reaches 4.9%.The third chapter introduces photoanode structure optimization based on three-dimensional ordered TiO₂ QDSSCs.Firstly,a three-dimensional ordered TiO₂film was prepared by using a polystyrene sphere template method.Compared with traditional two-dimensional TiO₂ film,the specific surface area of the oxide film is enlarged,and sufficient QDs loading is ensured.Subsequently,a new interfacial modification,i.e.,the SiO₂ passivation layer,was introduced onto the photoanode to improve the transmission of electrons in photoanode,and the recombination of electron-hole pairs was suppressed.Eventually,the photoelectric conversion efficiency of QDSSCs is improved.In this study,the optimization of the QD sensitizer and the interface modification of the photoanode shave improved the photoelectric performance of the QDSSCs.