The Study Of Nickel Oxide Nanoparticles For Efficient Hole Transport In P-i-n And N-i-p Perovskite Solar Cells

Threaten with energy crisis and environmental pollution,developing sustainable and clean energy become one of the most important thing.Solar photovoltaics bring us the hope to solve above problems.Organic-inorganic hybrid perovskite solar cells（PVSCs）naturally been the attractive research area because of its highly efficiency and low cost.Organic-inorganic hybrid perovskite materials have drawn considerable attention because of their outstanding opto-electronic properties,solution processability and rapid increased power conversion efficiency.Since Miyasaka and coworkers first introduced perovskite materials into photovoltaic community,different device configurations including mesoscopic and planar architectures based device have been reported.However,mesoscopic PVSCs usually employ a high temperature sintered mesoscopic layer as scaffold,which will increase the fabrication cost and limit its compatibility with flexible substrates.In planar devices,the charge transport materials play a vital role in selective electron/hole extraction,where an ideally charge transport material should possess a suitable energy level,sufficient conductivity,and good charge extraction capacity.In the pursuit of highly stable and low-cost PVSCs,all-inorganic charge transport layer appear to be promising.However,there is limited success on low temperature processed inorganic transport materials,particularly hole transport materials,that have satisfied thermal/chemical compatibility with perovskite materials.To solve above problems,for the first time,a low-temperature solution-processed NiO_x thin film composed of pre-synthesized NiO_x,was successfully employed as hole transport layer in both regular（n-i-p）and inverted（p-i-n）planar organic-inorganic hybrid PVSCs.The deposited perovskite morphology,the perovskite/NiO_x interfaces,and the corresponding carrier dynamics can be tuned with suitable surface treatment of the NiO_x thin film,resulting in a much enhanced fill factor and short circuit current density.On the basis of the optimized NiO_x thin film,a promising power conversion efficiency（PCE）of 15.9%was obtained based on a indium tin oxide glass/ITO/NiO_x/perovskite/phenyl-C61-butyric acid methyl ester（PCBM）/bathocuproine（BCP）/Ag configuration,and 11.8%was obtained for the planar PVSCs with PEN/ITO substrate.More importantly,the attempt on the employment of NiO_x in the regular structure with a fluorine doped tin oxide FTO/TiO₂/perovskite/NiO_x/Au configuration shows a PCE of 9.11%,which is five-fold improvement of the power conversion efficiency when compared with hole transport materials free device（1.81%）with a FTO/TiO₂/perovskite/Au configuration.It indicates the promise of nanocrystals based NiO_x HTL in the development of regular structure.This work represents a significant step on the exploration of all-inorganic charge selection layer and stable PVSCs in both regular and inverted device configuration.