Application Of MoS₂ Quantum Dots And Amorphous Graphene In Organic Solar Cells

The over exploitation and use of fossil energy has a huge impact on the earth’s ecological environment,and it is necessary to develop new clean energy.Among them,organic solar cells,as one of the important members of new energy sources,have problems such as low photoelectric conversion efficiency and poor device stability that urge to be solved.And improving the energy level matching and interfacial contact between active layer and electrode is the key to solve these problems.It is found that by rationalizing the electrode,introducing anode interface materials,adjusting the work function of the electrode,and improving the interfacial contact between the electrode and the active layer,it is expected that the device efficiency can be improved.In this thesis,molybdenum disulfide quantum dots and amorphous graphene composites were obtained by a simple solvent heat treatment and used to modify the anode of organic solar cells,and the main research contents are as follows:1.Molybdenum disulfide quantum dots（Mo S₂ QDs）were obtained by acetone etching of molybdenum disulfide powder,and the nano size an d the structure of few layers make them have good electrical conductivity,and the resulting Mo S ₂ QDs were used as the anode interface layer in organic solar cells.In addition,the UV-ozone treatment reduces the roughness of Mo S ₂ QDs film formation,which is beneficial to improve the interfacial contact,making the devices based on PTB7-Th:PC₇₁BM active layer system resulted in a device fill factor of 56.02%and a photovoltaic efficiency of9.76%.2.Oxidative cutting of graphene is carried out by using th e oxidant generated in the process of etching molybdenum disulfide with acetone to obtain amorphous graphene.This process not only introduces some oxygen-containing groups on the basal plane of graphene,but also conducts oxidative cutting through"top-down"The pathway partially converts graphene into amorphous carbon.The obtained amorphous graphene is spin-coated to form a film after dispersion,followed by annealing and ultraviolet ozone post-treatment,and the material is assembled as an anode interfa ce material into a device with PCE-10:PC₇₁BM as the active layer.The device has the best photovoltaic performance.The open circuit voltage Voc reaches 0.76 V,and the photoelectric conversion efficiency reaches 8.42%.Among them,UV ozone tre atment for 8 min increased the-COOH ratio in amorphous graphene from 7.73%to 10.83%,and the work function increased from 4.12 e V to 4.53 e V,which can effectively match the HOMO energy level of the active layer donor.The results show that the amorphous graphene prepared by this method can be used as a good anode interface material.