Study On The Effects Of Metal Oxide Transport Layer On The Performance Of Perovskite Solar Cells

In recent years,the perovskite solar cells(PSCs)have excellent power conversion efficiency(PCE)at the same time of low cost and facile fabrication process,which makes it have great theoretical research value and practical significance in the third-generation of photovoltaic devices.Since the perovskite structure first applicant in the photovoltaic field in 2009,the certified PCE of the PSC has been achieved 24.2%in ten years.As the device efficiency continues to increase,the long-stability has become an important issue in determining the continued development and industrialization of PSCs.This work of this thesis is mainly focused on improving the efficiency and the device stability of PSCs,mainly involving the introducing of different oxides as the transport layers to enhance the performance and stability of the device.The main contents of this essay include the following three parts:1.The effects of ZnO nanorod arrays(ZnO NRs)as the electron transport layer on the performance of the inorganic PSCs were investigated.The ZnO NRs is utilized to replace the TiO2 in the CsPbIBr2 PSCs and the PCE of the device has increased to 4.86%.Then,we use the PCBA to modify the interface of the ZnO NRs and the efficiency has been enhanced to 6.17%.The research shown that nanostructured ZnO NRs can effectively enhance the thickness of CsPbIBr2 PSCs compared to the planar TiO2.After interfacial modification,the perovskite can be better deposited and infiltrated into the ZnO NRs.Finally,it can improve the absorption of sunlight by perovskite active layer,reduce the interfacial defects,increase the mobility of electrons and enhance the photoelectric performance of devices.Beside this,due to the perovskite can penetrate into nanorods well,a dense and non-porous perovskite film can be formed,and the device will have a good stability.The device can maintain over 80%efficiency under the condition of not encapsulated and stored in air for 300h.2.The effect of CeOx thin film as the electron transport layer prepared by sol-gol method on the performance of the PSCs was studied.Through investigate different concentrations of CeOx precursor solution and finally obtain a PCE of 17.47%when the concentration of the precursor solution is 0.01M.The results show that CeOx film as electron transport layer can get a better energy level matching with perovskites,which can better enhance the electron extraction ability and effectively block the recombination of hole electron pairs.At the same time,use the inorganic transfer material replace the traditional organic transfer materials(PCBM)can make the devices have better performance in stability.3.The effect of using all inorganic materials as the transport layer on the performance of inorganic PSCs was investigated.An all inorganic PSC with ITO/NiOx/CsPbIBr2/CeOx/Ag structure was constructed by use inorganic materials.Finally,a relatively high PCE can be achieved in this inverted inorganic PSCs.Because most of the small molecules will be polymerized under high temperature annealing,which hinders their application in PSCs and will reduce the stability of the device.Therefore,remove the organic transport layer or use of inorganic transport materials can solve the stability of perovskite solar cells.