Application Of NiO_x Hole Transport Material In Inverted Planar Perovskite Solar Cells

Perovskite solar cells is considered as one of the most potential new photovoltaic technologies because of its low cost and high efficiency.Its conversion efficiency has increased rapidly from 3.8%in 2009 to 25.7%at present.The development of hole transport materials plays an important role in the development of perovskite solar cells.Among them,NiO_x has attracted extensive research because of its simple preparation,low cost,high transmittance and good stability.However,compared with organic PTAA and other hole transport materials,the efficiency of perovskite solar cells based on NiO_x is still low.The key problem lies in the electrical conductivity of NiO_x itself and the interface contact performance between NiO_xand perovskite thin films.This thesis mainly focuses on NiO_x hole transport material and its application in reverse perovskite solar cells,focusing on the conductivity of NiO_x and interface contact with perovskite.On the one hand,photoconductive effect is used to significantly improve the conductivity of NiO_x thin films under light;on the other hand,poly[3-(4-carboxybutyl)thiophene]is used to modify the surface of NiO_x to successfully achieve a good contact between NiO_x and perovskite.Finally,a highly efficient and stable NiO_x-based reverse perovskite solar cells is achieved.The main contents are as follows:(1)The photoconductive effect was used to improve the conductivity of NiO_x thin films.The preparation of phthalocyanine(Pc)-NiO_x photoconductive interface and its effect on the performance of perovskite cells were studied systematically.When phthalocyanine is introduced into NiO_x film,the hole produced by phthalocyanine can be transferred to NiO_x,so as to increase the hole concentration of NiO_xand improve its conductivity.Based on this,we realized a NiO_x-based reverse perovskite battery with an efficiency of 21.68%,which was one of the highest efficiency of NiO_x-based reverse battery at that time.In addition,the perovskite solar cells also showed good stability and maintained more than 95%of the initial efficiency after aging at 85? for 800 h.(2)Poly[3-(4-carboxybutyl)thiophene](P3CT)was used to modify NiO_x to solve the interface contact problem between NiO_x thin film and perovskite layer.The double interface modification of NiO_x and perovskite thin film by P3CT and its effect on device performance were studied systematically.By introducing P3CT layer between NiO_x and perovskite,the carboxylic acid group of P3CT can chemically interact with NiO_x to improve its interface contact performance,while its thiophene group can coordinate with perovskite and passivate the defects of perovskite film at the interface of NiO_x.Thus,the effective modification of NiO_x and perovskite interface can be realized,and the efficiency of the device is increased to 21.27%.In addition,the stability of the device has also been significantly improved.After 800h thermal stability test in 85? in N₂ atmosphere,the conversion efficiency is still more than 79%of the initial value.