| In this thesis,based on the advantages of in situ nondestructive detection of Raman spectroscopy,the Ti O2-based photovoltaic devices containing p-n heterojunctions were studied by in situ Raman spectroscopy.The specific research contents are mainly divided into two parts.First,photodetector（PD）containing p-n heterojunction were investigated using Raman spectroscopy,and a new method for in situ characterization of PD under working conditions was established.Secondly,using Raman spectroscopy to study dye-sensitized solar cell（DSSC）containing p-n heterojunctions,it is revealed that p-n heterojunctions play a role in improving the open circuit voltage(Voc)and conversion efficiency（η）of DSSC.1.In situ Raman spectroscopy to study the effect of p-n heterojunction on the performance of PD.Many studies have shown that p-n heterojunctions can significantly enhance the responsivity of photodetector（PD）.However,the specific enhancement mechanism of p-n heterojunctions remains unclear.In this thesis,the p-n heterojunction PD composed of p-NiO nanoparticles（NPs）and n-Ti O2nanotube array（TNA）was investigated by in situ Raman spectroscopy.The results show that the built-in potential field at the NiO/Ti O2interface reduces the charge transfer resistance and changes the vibrational frequency of the phonon modes of Ti O2.This part of the work reveals experimental evidence for the existence of electron-phonon coupling effect in the device.In situ Raman spectroscopy proved to be a powerful tool to aid in the fabrication of PD with high response performance.2.In situ Raman spectroscopy to study the effect of p-n heterojunction on the performance of DSSC.Many studies have shown that the p-n heterojunction has a significant effect on the open circuit voltage(Voc)of dye-sensitized solar cell（DSSC）,which is also confirmed in this part of the work.However,the mechanism of Voc enhancement by p-n heterojunction is not clear.In this thesis,DSSC containing p-BiOCl/n-Ti O2 nanotube array（TNA）heterojunctions composed p-BiOCl nanosheets n-TNA were investigated using in situ Raman spectroscopy.Compared with DSSC composed of TNA as photoanode,the Voc of DSSC composed of p-BiOCl/n-TNA photoanode is significantly enhanced.The results show that the built-in electric field at the FTO/Ti O2/BiOCl photoanode interfaces effectively reduces the recombination of electrons-holes pairs,which is more conducive to the transport of photogenerated carriers inside the DSSC,thereby further improves the performance of the DSSC.In this thesis,in situ micro-Raman imaging technique is also used to probe the changes of internal components of DSSC in real time,and it is proved to be a powerful tool to assist the fabrication of DSSC with high conversion efficiency. |
