Structural Design,modification And Photoeletrochemical Performances Of P-type CuSCN Based Inorganic Hole Transfer Layer Materials

P-type CuSCN as an inorganic semiconductor material,has aroused great interest in solar cells,photodetectors,light-emitting diodes and field-effect transistors,due to the suitable band energy position,excellent chemical stability,high hole mobility and low cost.However,it is still a challenge to further improve the charge transport performance of CuSCN.In this thesis,heterojunction thin films based on p-type CuSCN were fabricated by electrochemical deposition and spin coating methods,in order to achieve hole transport layer(HTL)with excellent photoelectrochemical performances,and thus promote the practical applications in the field of solar cells.Detailed description of the research was presented as following:(1)Electrochemical deposition was employed to prepare CuSCN films.After that,in-situ grown Cu₂O/CuSCN heterojunction films was presented by simple strong alkali treatment process.The Cu₂O/CuSCN materials with fast charge transfer and low charge recombination were successfully obtained.In addition,the morphology and charge transfer performances of Cu₂O/CuSCN can be controlled by changing the treatment time of strong alkali.Compared with pure CuSCN,the Cu₂O/CuSCN heterojunction can promote band bending,accelerate charge separation and reduce charge recombination,which has been further confirmed by photoelectric chemical test results.(2)Compared with CuSCN thin film,CuS QDs/CuSCN thin film prepared by one-step electrodeposition with synthesised CuS QDs can greatly improve the photocurrent response,carrier lifetime and carrier transport.The significantly improved photochemical properties can be attributed to the construction of CuS QDs/CuSCN heterojunction,which promotes the effective separation of photogenic electrons and holes,reduces the recombination of photogenerated carriers,and finally achieve rapid hole transfer.As a result,the carriers transport efficiency and lifetime were improved by 1.23 and 3.7 times,respectively.(3)In this chapter,two-dimensional material BP with few layers was prepared by ultrasonic stripping method,and a BP/CuSCN heterojunction material was successfully synthesized by spinning coating,which could accelerate charge separation and reduce charge recombination.All of these could be confirmed by EIS,charge extraction,IMPS Finally,the photocurrent density and carriers transport rate were improved by 50 and2.5 times,respectively.