Research On Performance Enhancement Of Perovskite Solar Cell Based On Core-shell Nanoparticles

Owing to the advantage of high absorption coefficient,high carrier mobility,electron-hole diffusion length,adjustable direct band gap and low exciton binding energy,organic inorganic halide perovskite solar cell has become the most promising solar cells.In the past ten years the conversion efficiency of perovskite solar cell has increased from 3.8%(2009)to 25.2%(2019),The efficiency of perovskite solar cell is still inferior to its theoretical limit.Among all the technical schemes,improving the electrical performance of perovskite solar cells is the best way to further improve the photoelectric conversion efficiency of perovskite solar cells.The interface modification,solvent engineering and additive has been efficient methods to suppress the defect state,which can effectively passivate the grain boundary or the surface defect state,reduced electrical loss and improved the carrier transmission rate.Additive passivation is an effective strategy to reduce electrical loss and decrease internal non-radiative recombination at grain boundaries.Core-shell metal nanoparticles with unique local plasmon resonance(LSPR)effect has aroused wide public concern.Nevertheless,most of studies focus on things through LSPR effect to improve light absorption ability on the perovskite solar cells.In this study,we investigated the effect of structurally specific core-shell metal nanoparticles when putting into different location,which can modify the electrical performance for perovskite solar cell and improve carrier generation and collection capacityFirstly,the gold-coated nickel oxide core-shell nanoparticles(Au@NiOx)were incorporated into mesoporous nickel oxide layer of inverted perovskite solar cell to investigate its effect of device performance.The inverted structure of perovskite solar cell has potential of relatively easy preparation process,low processing temperature,low cost and insignificant hysteresis.The stability of the device with inorganic nickel oxide as hole transport layer is greatly improved.However,nickel oxide with low conductivity may cause carrier recombination when directly applied as a P-type mesoporous layer,which results in short-circuit current and filling factor loss thus reduces the device performance.Therefore,the core-shell nanoparticles are utilized to modify the mesoporous NiOx layer to improve the carrier migration ability owing to the local plasmon resonance effect of the metal nanoparticles.Meanwhile,the Au@NiOx could improve the conductivity of the hole transport layer,which enhance collection capacity of the hole transport layer.The photoelectric conversion efficiency based on the gold-coated nickel oxide core-shell nanoparticles of inverted perovskite device is up to 19.87%with negligible hysteresis effect.Secondly,the deep level traps induced by charged defects at the grain boundaries(GBs)of polycrystalline organic-inorganic halide perovskite(OIHP)films serve as major recombination centers,which are unavoidable because of the own nature of those materials and their low-temperature solution-based preparation processes.Here,we devised a new type of core-shell metal nanoparticles(Au@PAT),which modified Au nanoparticles with ultrathin and compact poly(3-aminothiophenol)(PAT)in situ since?-conjugation phenylamine molecules.When the Au@PAT adds to precursor solution of perovskite,it can be introduced absorbed layer.The result suggested that the introduction of core-shell metal nanoparticles decrease the deep trap density,which results from the strong coupling at the metal/perovskite interface in GBs.As a result,the MAPbI3 device based on Au@PAT achieved the best PCE of 20.54%with robust operational stability.Our work provides unambiguous evidence that core-shell metal nanoparticles may be one type of excellent passivators to overcome the recombination losses in perovskite solar cells.