Preparation And Performance Of Perovskite Cell Devices Based On Optical Absorption Layer Optimization

Among the current numerous photovoltaic devices,perovskite solar cells（PSCs）have developed rapidly due to the significant advantages of perovskite materials such as strong light absorption ability,high carrier mobility and adjustable bandgap width.So far,the energy conversion efficiency（PCE）of PSCs has exceeded 25%.Although PSCs have made many significant improvements,there are still some challenges,one of which is how to improve the quality of perovskite films to improve the efficiency and stability of PSCs.This thesis adopted additive engineering,solvent engineering and component control strategies to improve the crystallinity of perovskite films,optimize film morphology and improve device performance.This article mainly consists of the following three parts of work:（1）Using the additive engineering strategy,4-carboxyphenyl isothiocyanate（CPIC）was used as the additive of perovskite optical absorption layer.The introduction of Lewis basic SCN^-group and-COOH group in CPIC could interact with Pb²⁺in perovskite films,passivate the lead ion defects in the films and improve the crystallinity and grain size of the films.The introduction of hydrophobic benzene rings in CPIC could effectively improve the stability of PSCs.The experimental results showed that when the concentration of CPIC was 0.5 mg m L^-1,the PCE of the device increased from 16.16%to 18.19%.Moreover,after 30 days of storage,its PCE remained at61.9%of its initial efficiency,effectively improving the efficiency and stability of PSCs.（2）Using the solvent engineering strategy,trimethyl phosphate solvent（TMP）was used as an additive in the perovskite light absorption layer to investigate its impact on the performance of the PSCs.The introduction of TMP solvents with weak alkalinity and lower polarity could passivate film defects,reduce non-radiative recombination and improve film quality.The experimental results showed that when 1.5%TMP was introduced,the XRD diffraction peak and PL peak intensity of the perovskite thin film were significantly increased,the V_OCof the device was increased to 1.09 V,the J_SCwas increased to 22.89 m A cm^-2and the PCE was also increased from 16.22%to 18.76%.The photoelectric performance of PSCs was significantly enhanced.（3）By utilizing the component control strategy,dimethylamine hydrochloride（DLHC）was used as an additive in the perovskite light absorption layer.The introduction of DMA⁺and Cl^-groups in DLHC could partially replace the MA⁺and I^-groups in MAPbI₃,forming the perovskite film with the MA_（1-x）DMA_xPbI_（3-y）Cl_ystructure,significantly increasing the J_SCand PCE of the devices.Moreover,the introduction of secondary amines in DLHC could weaken the hydrogen bonding between the active layer and environmental water,enhancing the stability of PSCs.The experimental results showed that when the concentration of DLHC was 0.2 mg m L^-1,the crystallinity of perovskite films increased,defects were reduced and light absorption efficiency was improved.The PCE of the PSCs increased from 16.42%to 18.91%and the water contact angle of the film increased from 40.3°to 68.4°.This provided a feasible method for achieving efficient and stable PSCs.