Preparation And Research Of Counter Electrode Of Perovskite Solar Cell

Organic-inorganic halide perovskites have attracted wide attention due to their high extinction coefficient,adjustable band gap,and long carrier diffusion distance.With continuous efforts and research,the certified photoelectric conversion efficiency?PCE?of perovskite solar cells?PSCs?has reached up to 25.2%,which showed a very high great development potential.However,there are some problems greatly limits their commercial applications of PSCs,including poor stability,containing heavy metals?Pb?,high cost of hole transport materials?HTMs?and metal electrodes,and the difficulty in large-scaling preparation.Therefore,in order to solve the problems of expensive HTMs and metal electrodes in PSCs,we conducted a series of researches.On the one hand,MXene,a two-dimensional material with high conductivity,has been employed as the substitution for expensive HTMs and metal electrode in conventional PSCs.On the other hand,high-quality copper nanowires?CuNWs?has been synthesized by hydrothermal method,and then applied into preparation of transparent electrodes in PSCs.?1?Preparation and application of MXene counter electrode.The Al elements in the Ti₃AlC₂ was etched by acid etching,and a two-dimensional material Ti₃C₂ with graphene-like structure was synthesized.Ti₃C₂ had high conductivity and a work function similar to Au,which could be used as the counter electrode replaces expensive HTMs and metal electrodes in PSCs.It reduced the cost of the device,avoided high-temperature and high-vacuum vapor deposition conditions,and simplified the preparation process.At the same time,we chose acetylene black as the electrode filler to modify the performance of the two-dimensional material Ti₃C₂,which could improve the conductivity of the electrode and enhance the extraction of holes.And we also chose polyvinyl acetate?PVAc?as the electrode binder.The benefit of PVAc was to achieve the seamless connection between the Ti₃C₂ counter electrode and the perovskite through hot-pressing.It could reduce the square resistance and interface resistance of the electrode effectively.At last,we got 13.83%PCE of PSCs with MXene counter electrodes,which showed good stability and reproducibility.?2?CuNWs electrode semi-transparent perovskite solar cells.Using CuCl₂ as the copper source,glucose as the reducing agent,and octadecylamine as the blocking agent,copper nanowires?CuNWs?were synthesized by hydrothermal method.After the by-product copper nanoparticles?CuNPs?were removed by further purification,CuNWs with high aspect ratio were obtained.A simple spraying method was used to prepare the CuNWs transparent electrode.The electrode had excellent conductivity and light transmittance.The average square resistance was 15?/?9?,and the light transmittance could be 75%.The transparent electrode and the perovskite half-cell were superposed and assembled to form a CuNWs electrode semi-transparent perovskite solar cells,with double light transmission functions.Further optimizing the electrode and interface of devices,the extraction and transmission of holes were enhanced.