Preparation And Performance Research Of Quantum Dot Sensitized Solar Cell Based On 1T-MoS₂ Counter Electrode

As a typical third-generation solar cell,quantum dot sensitized solar cells（QDSSCs）have received great attention due to its low-cost,simple fabrication process and the intriguing physical properties of quantum dots,such as the quantum size effect and multiple exciton collection.The counter electrode（CE）is one of the core components of QDSSCs,and its electrocatalytic activity directly affects the photovoltaic performance of QDSSCs.1T-MoS₂has recently become a research hotspot in the field of electrocatalysis due to its excellent conductivity and abundant active sites.In this paper,1T-MoS₂ and its composite materials were prepared by hydrothermal method.The crystal structure morphology and chemical species of the samples were analyzed by XRD,Raman,SEM,TEM and XPS.Furthermore,the electrochemical test was used to study electrocatalytic reduction activity on S_n^2-,and the QDSSCs were assembled with Cd S/Cd Se co-sensitized Ti O₂ photoanode to test the photoelectric properties.The multi-walled carbon nanotubes（CNT）were annealed in the air to be activated,and then 1T-MoS₂ was induced on the surface of activated carbon nanotubes（a CNT）by hydrothermal method.The results show that the adding of a CNT successfully induces the formation of 1T phase,and significantly improves the catalytic activity of CEs.When the adding amount of a CNT is 150 mg,the charge transfer resistance(R_ct)of the MoS₂/a CNT CEs is smallest,with a value of only 0.91Ω.and the photoelectric conversion efficiency（PCE）of the QDSSCs can reach 4.53%,which is much higher than that of the QDSSCs assembled with MoS₂ and a CNT CEs.For the first time,the 1T-MoS₂ was prepared by using F127 micelles formed under acidic conditions as a soft template.When the adding ratio of F127 is 3%,1T-MoS₂ is in the shape of honeycomb-like microspheres,and the R_ct of the CE is smallest,showing excellent catalytic activity and stability.Compared with the F127 addition of 0%,1%and 5%,R_ctdecrease by 79.44%,60.95%and 57.14%respectively.The PCE of QDSSCs assembled with Ti O₂/Cd S/Cd Se/Zn Se photoanode can reach 6.03%,the photovoltaic performance is greatly improved.Through the spatially confine of the NiCo-LDH self-sacrificial template,NiCo₂S₄/1T-MoS₂ nanospheres with a diameter of about 100 nm were successfully prepared which has a heterogeneous structure.And the metal 1T phase in the composite is as high as84.28%.The R_ct of the nanosphere counter electrode is only 0.84Ω,showing excellent electrocatalytic activity.Furthermore,the PCE of QDSSCs assembled with NiCo₂S₄/1T-MoS₂as CE is as high as 5.32%,and its fill factor is 0.68,which is the highest record of QDSSCs currently.