Preparation Of Ti₃C₂-based Counter Electrode Quantum Dot Sensitized Solar Cells

Quantum-dot sensitized solar cells are the third-generation solar cells,which have the advantages of low cost and high photoelectric conversion efficiency,and thus become ideal photovoltaic devices for solving energy problems and environmental problems.In this thesis,Ti₃C₂ was prepared by HF acid etching using Ti₃AlC₂ as raw material,Ti₃C₂/CuS composite was prepared by ion exchange method,Ti₃C₂ was hydrothermally modified by sodium sulfide solution,and the corresponding counter electrode was prepared by drop coating method.XRD and SEM were used to characterize the structure and morphology,and electrochemical tests were carried out to characterize the catalytic activity.A photoanode with CdSe as quantum dots was prepared by manual and microinjection pump assisted continuous ion layer adsorption and reaction.The prepared photoanode,counter electrode and polysulfur electrolyte were assembled into a quantum dot sensitized solar cell for photoelectric performance test.Ti₃C₂ of the accordion structure can be obtained by stripping the aluminum atom layer in Ti₃AlC₂ with HF acid.Univariate experiments and orthogonal experiments show that when the concentration of HF acid is 40 wt%,the volume is 60 mL,and the reaction is 48 h,the layered structure of Ti₃C₂ is obvious,the layered structure is many and thin,and the etching effect is the best.Different mass ratios of Ti₃C₂ and CuS composite counter electrodes were prepared by ion exchange method.Experiments show that when the mass ratio of Ti₃C₂ to CuS is 1:2,the catalytic activity of the electrode is best when the five layers are applied,and the battery structure is optimal.The charge transfer impedance is 2.96Ω·cm^-2 and the exchange current density is 10.26 mA·cm^-2.The prepared TiO₂/CdS/CdSe/ZnS photoanodes were assembled into a quantum dot sensitized solar cell,and the photoelectric performance test was carried out under the AM1.5 spectral condition light source of 100 W·cm^-2.The short-circuit current,open-circuit voltage,fill factor,and photoelectric conversion efficiency were 21.13 mA·cm^-2,0.54 V,0.45,and 5.13%,respectively.The good performance of the battery is mainly due to the good catalytic activity of CuS and the good charge transport orbit provided by Ti₃C₂.The surface modification of Ti₃C₂ was carried out by Na₂S hydrothermal method.The effects of curing time,vulcanization temperature and Na₂S dosage on the properties of Ti₃C₂materials were investigated.The experimental results show that the vulcanized Ti₃C₂ has strong catalytic activity when the vulcanization time is 12 h,Na₂S is 0.03 M,and the temperature is 120°C.The charge transfer resistance is 9.31Ω·cm^-2 and the exchange current density is 4.59mA·cm^-2.After the battery was assembled with the photoanode,the short-circuit current density,open-circuit voltage,fill factor and power conversion efficiency were 7.50 mA·cm^-2,0.50 V,0.41,and 1.41%,respectively.The micro-injection pump was used to explore the ion layer adsorption and reaction process to prepare CdS quantum dot sensitized TiO₂ film,and the photoelectric properties of TiO₂/CdS photoanode under different conditions were investigated.The experimental results show that the volume of the two micro-samplers of precursor and deionized water are 2.5 mL and 20 mL,respectively,and the time for the precursor and deionized water to immerse the film is 40 s,the battery assembled by this photoanode has a photoelectric conversion efficiency of1.04%.