The Study Of CdS/CdSe Quantum Dots Co-sensitized Solar Cells Based On Zinc Titanium Hydrotalcite-like Compounds

Hydrotalcite-like compounds(also known as HTlc)are hydroxides composed of two or more metals,which are widely used because of their many specific properties,such as large specific surface area etc.In this paper,zinc-titanium HTlc was synthesized by urea hydrolysis method,and a powder of zinc-titanium composite oxide(also known as MMO)was obtained by simple grinding and calcination procedures.A simple blade coating method is applied to photoanodes of quantum dot sensitized solar cells(also known as QDSSC)in order to achieve better results.By synthesizing CdS/CdSe QDs,CuS counter electrodes,and optimizing the electrolyte,QDSSC based on zinc-titanium HTlc have better photoelectric conversion efficiency.The work is summarized as follows:1.Polyiodide(I-/I3-)electrolyte has good catalytic effects in dye-sensitized solar cells(DSSC).However,the application of polyiodide electrolyte to QDSSC has an unsatisfactory effect,which not only has low catalytic efficiency,but also has a corrosive effect on QDs.In this paper,the polysulfide electrolyte(S2-/Sx2-)was synthesized and applied to QDSSC based on zinc-titanium MMO and CdS QDs system,and its performance was tested under a standard solar simulator.Compared with QDSSC of polyiodide electrolyte,it was found that the QDSSC of the polysulfide electrolyte system has a higher current and a higher photoelectric conversion efficiency.2.QDs can adjust their energy absorption band width by adjusting their block size to adjust their absorption spectrum range for sunlight.However,due to the structural limitation of a single quantum dot,the adjustment range of the band is limited,so that QDs of two different bandgap can be synthesized and combined to form a composite structure,thereby increasing its absorption for sunlight and improving the efficiency of QDSSC.In this paper,CdS QDs are synthesized by successive ionic layer adsorption and reaction(SILAR),and CdSe QDs are synthesized by chemical bath deposition(CBD).By co-sensitizing and adsorbing on a photo-anode based on zinc-titanium MMO and comparing it with a single CdS quantum dot,it was found that the photoelectric conversion efficiency of the QDSSC was greatly improved.3.The counter electrode carries the electrons of the external circuit,and catalyzes the interaction of electron-hole pairs at the interface between the electrode and the electrolyte.However,in the conventional Pt counter electrode and polysulfide electrolyte system,S2-is easily adsorbed on the surface of the Pt electrode,thereby reducing its conductivity and catalytic activity.Therefore,we synthesized a CuS counter electrode through CBD,and obtained the CuS counter electrode with the best effect by controlling the reaction time of the chemical bath.Compared with the QDSSC of Pt electrode system,the filling factor is improved a lot.Therefore,the photoelectric conversion efficiency is also greatly improved.