An organic small molecular material(N,N-dicarbazolyl-3,5-benzene,mCP)with hole transporting ability was introduced as an interfacial barrier layer between the metal halide perovskite luminescent layer(CsPbBr3)and the strongly acidic polymer poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)(PEDOT:PSS)to protect CsPbBr3 from corrosion.The study showed that mCP not only can spatially isolate CsPbBr3 and PEDOT:PSS to inhibit the degradation of PEDOT:PSS on the CsPbBr3 luminescent layer,but also can improve the film quality,making the coverage of the perovskite film higher and the grains smaller,and thus reducing the quenching defect.At the same time,the introduction of mCP can improve the hole injection and transport ability,resulting in more excitons generated under the same voltage.Since mCP has a higher lowest e-lectron unoccupied state and a larger energy gap than PEDOT:PSS,which can confine excitons better in the lu-minescent layer,improving the radiation recombination of excitons,thereby improving the electroluminescence efficiency of the device further.Compared with the reference device without mCP,the electroluminescence per-formance of the 3D CsPbBr3 perovskite light-emitting diode(PeLED)based on mCP was significantly improved,achieving a maximum current efficiency of 4.86 cd/A.Subsequently,this method was also proven to be feasible in quasi-two-dimensional PeLEDs based on PEA2Csn-1PbnBr3n+1,exhibiting the maximum current efficiency of 24.79 cd/A.
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