Application Of Organic Semiconductor Charge Transport Layer In Antimony Selenide Thin Film Solar Cells

Solar energy is an inexhaustible source of clean energy.Solar cell power generation is an important direction for the use of new energy.In recent years,antimony selenide?Sb₂Se₃?materials have received more and more attention in photovoltaic applications due to their excellent photoelectric characteristics,low cost,stable chemical properties,and low toxicity.Since antimony selenide is a P-type semiconductor,it is necessary to introduce an N-type semiconductor to build a PN junction.The main work of this paper is to introduce organic semiconductor materials PTCDA and C₆₀0 as the electron transport layer of antimony selenide thin film solar cells.In addition,we also used organic semiconductor material NPB as the hole transport layer of antimony selenide thin-film solar cells to further improve the photoelectric conversion efficiency of solar cells.The specific work is as follows:First,we prepared the antimony selenide film by vacuum thermal evaporation,and then annealed the antimony selenide film in an atmosphere containing selenium.The crystal structure and optical properties of the antimony selenide film were characterized by XRD,SEM,Absorption spectrum,Raman spectroscopy and other test methods.Carrier mobility of antimony selenide film was studied using space charge limited current model.The results show that annealing in an atmosphere containing selenium can improve the quality of the antimony selenide film crystals and increase the optical absorption coefficient and carrier mobility of the antimony selenide film.Next,we used PTCDA and C₆₀0 as the electron transport layer to prepare solar cells with structures of ITO/NPB/Sb₂Se₃/PTCDA/Alq₃/Al and ITO/NPB/Sb₂Se₃/C₆₀/Alq₃/Al.Through process optimization,the highest photoelectric conversion efficiency of the devices reached 4.2%(open circuit voltage=0.39 V,short circuit current density=21.5 mA cm^-2,fill factor=0.50)and 4.9%(open circuit voltage=0.42 V,short circuit current density=21.6 mA cm^-2,fill factor=0.55).In addition,we also studied the recombination mechanism of photo-generated carriers in the device.The results show that the bimolecular recombination?Langevin?mechanism dominates,while the trap-assisted recombination?SRH?mechanism dominates.In addition,we also studied the role of hole transport layer NPB and TCTA in antimony selenide thin film solar cells.The results show that NPB is more suitable as a hole transport layer than TCTA.The introduction of the NPB layer can effectively suppress the carrier recombination near the ITO electrode interface in the device and extend the life of the carrier,thereby significantly improving the performance of the device.