Study On The Composition Regulation And Properties Of Electron Transport Layer For Perovskite Solar Cells

Due to perovskite materials in perovskite solar cells have high light absorption coefficient,long charge diffusion length and suitable band gap width,the efficiency of solar cells prepared based on this material has increased rapidly from 3.8%in 2009 to23.7%as reported so far.Therefore,it has become a research hotspot at home and abroad.Among them,most efficient solar cells are prepared with TiO₂ and ZnO as electron transport layers.TiO₂ has high electron extraction capacity and good stability,but the carrier concentration and conductivity need to be improved,and it has photodecomposition effect on perovskite,so the stability of the battery is reduced.However,the preparation technology of ZnO nanoparticles still needs to be improved.In this paper,lanthanum-doped TiO₂ porous layer,PCBM modified TiO₂porous layer and ZnO substituted TiO₂ electron transport layer were successively introduced to analyze the performance of the prepared battery devices,and the following results were obtained:Different parameters of La?NO₃?₃·6H₂O doped TiO₂ porous precursor solution were prepared by solution method.The results show that doping has a great influence on short circuit current density and photoelectric conversion efficiency.When doped with 5%La,the average efficiency is 14.44%,which is about 2%higher than the average efficiency of the undoped battery?12.33%?.Lanthanum doped TiO₂ porous layer has better performance mainly because it greatly increases the carrier concentration and improves the extraction speed of electrons and holes,thus reducing the combination of electrons and holes and improving the carrier survival time.By introducing PCBM interface modification layer,different concentrations of PCBM solution were prepared to modify the TiO₂ porous layer/perovskite interface,and the influence of different modification concentrations on the comprehensive performance of the battery was studied.The results show that when the modified concentration of PCBM is 2.5mg/mL,it can achieve an efficiency of 16.37%and has a good stability,because PCBM has strong electronic transmission capacity and hydrophobic capacity,and can effectively reduce the degradation of MAPbI₃ by TiO₂.The solution of ZnO nanoparticles was prepared by sol-gel method,and ZnO was used to replace TiO₂ electron transport layer,so as to explore the influence of ZnO with different spin coating number on the photoelectric performance of battery devices.The results show that the efficiency of the device can reach 10.84%when the ZnO is applied in five layers.The introduction of ZnO not only simplifies the battery preparation process but also saves energy and cost.