Research On Preparation And Photovoltaic Properties Of Quantum Dot Sensitized Solar Cells Based On MoS₂ Counter Electrode

The quantum dot sensitized solar cell is a novel third-generation solar cell,which has environmental-friendly characteristics,simple preparation process,low material cost,and high theoretical power conversion efficiency,therefore,the development prospect is very bright.The counter electrode is an important component of quantum dot sensitized solar cells.MoS₂/CNTs and MoS₂/Ni Foam composite material were prepared by hydrothermal method,the MoS₂/CNTs counter electrodes were prepared by drop coating method,MoS₂/Ni Foam counter electrodes were prepared,and assembled into a complete quantum dot sensitized solar cell with CdS/CdSe photoanode and polysulfide electrolyte.Subsequently,a micro-injection pump was used to assist the deposition of photoanodes with CdS/CdSe as quantum dots,and the photoanode was assembled into a quantum dot-sensitized solar cell with a counter electrode and electrolyte to test their photovoltaic properties.The research contents of this paper are as follows:?1?MoS₂/CNTs composites were prepared by a one-step hydrothermal method,the effects of the content of carbon nanotubes introduced and concentration of suspension on the catalytic activity of MoS2/CNTs composite material were investigated.The appropriate content of carbon nanotubes introduced can improve the catalytic activity of the counter electrode.When 0.01 g of carbon nanotubes were introduced into 0.25 g of sodium molybdate and 0.4 g of thiourea,and the obtained MoS₂/CNTs material was calcined under a N₂ atmosphere,the catalytic activity of the counter electrode is optimal.The charge transfer impedance was 1.39?and exchange current density was 10.08 mA cm^-2.The experimental results show that,under the condition of AM1.5 standard illumination,Quantum dot sensitized solar cell based on the optimal MoS₂/CNTs counter electrode achieved a power conversion efficiency of 5.05%,higher than that of MoS₂,CNTs and other MoS₂/CNTs.?2?MoS₂/Ni Foam composites were prepared by hydrothermal method,the influence of Ni Foam on the electrocatalytic activity of the counter electrode was studied.The results shows that the introduction of Ni Foam can enhance the electrocatalytic activity of the counter electrode.The MoS₂/Ni Foam-180 composite material synthesized at 180°C has the optimal catalytic activity.The charge transfer impedance was 0.51?and exchange current density was11.31 mA cm^-2,attributed to the three-dimensional network structure of Ni Foam,flower-like structure of MoS₂ and synergistic catalysis of MoS₂ and Ni Foam.Quantum dot sensitized solar cell based on the optimal MoS₂/Ni Foam counter electrode achieved a power conversion efficiency of 4.02%,higher than that of the MoS₂ and Ni Foam counter electrode.?3?The micro-injection pump was used to assist the deposition of CdS/CdSe quantum dots.We investigated the influence of the number of CdS layers,the number of CdSe layers and the propulsion speed of the micro-injection pump on the light absorption capacity of the photoanode.After UV-visible spectroscopy analysis,it was found that the proper number of deposited layers had a positive effect on the light absorption capacity of the photoanode.When4 layers of CdS and 3 layers of CdSe were deposited,and the propulsion speed was 3 mm/min,the deposited photoanode had the best light absorption capacity,and the band gap was 2.29 eV.The results show that,Based on the optimal photoanode,the quantum dot-sensitized solar cells assembled with the MoS₂/CNTs-2 and MoS₂/Ni Foam-180 counter electrodes,and their power conversion efficiencies were 4.63%and 3.91%,respectively.The micro-injection pump assists in the deposition of CdS/CdSe quantum dots,which is simple in operation and saves time,and provides a new idea of convenient operation.