Preparation And Performance Of Perovskite Cell Devices Based On Active Layer Optimization

As a new type of organic-inorganic hybrid semiconductor materials,advantages of perovskite are mainly reflected in its low cost,high absorption coefficient,high luminous efficiency,and long carrier diffusion length.Currently,there are several ways to improve the performance of PSC（Perovskite Solar Cell）devices,such as solvent engineering,interface engineering,preparation process optimization,device structure improvement,element doping,additive engineering,etc.Each method has different characteristics and improvement effects.Among them,additive engineering and element doping are two simple methods which have been commonly used for the adjustment and optimization of the morphology of the perovskite layer.In this paper,the perovskite layer was optimized via additive engineering and dopants,which has affected the crystallization process of the perovskite layer and improve the photoelectric conversion efficiency of the PSC device.It can be divided into the following three parts.（1）The-SCN group in 4CI（4-Carboxyphenyl Isothiocyanate）is a type of Lewis acidity and can coordinate with the unpaired metal ion Pb²⁺at the grain boundary of the perovskite film to form a Lewis acid-base adduct.The coordination reaction can affect the crystallization and nucleation of perovskite crystals,and effectively reduce the density of the defects around the unpaired Pb²⁺,thereby reducing the generation of non-radiative recombination and improving the performance of the device.Finally,it was found that when the 4CI concentration was 0.5 mg/m L,the device optimization effect was the best,and the device efficiency increased from 15.34%to 17.28%.However,4CI is expensive,difficult to store,and the efficiency of PSC device is not very high after4CI optimization,so further exploration has been carried out.（2）With further research on the additive engineering,we found that both the imine（-C=N）and the cyano group（-C≡N）in the DICY（Dicyanodiamide）molecule have Lewis acidity,and due to their inducing effect,the C-N in the molecule exhibits Lewis basicity.Therefore,the functional groups in DICY can form coordination bonds with metal ions(Pb²⁺)on the surface of the perovskite through a synergistic effect,thereby forming Lewis adducts to passivate the surface defects of the perovskite layer.This optimization effect can eliminate the deep-level traps of the perovskite film,reduce the probability of carrier recombination,and enhance the charge transport capability of the perovskite.（3）In order to explore ways to improve device stability,we use a type of guanidine derivative-guanidine hydrochloride（GUAHCl）as a dopant,trying to explore the effect of GUA replacing the A position.The results show that an appropriate amount of GUA can be incorporated into the crystal unit to form a two-dimensional perovskite structure,increase the band gap width,and improve device stability and photoelectric performance.