Research On Perovskite Solar Cell Based On Magnetron Sputtering ZnO

In recent years,organic-inorganic hybrid perovskite solar cells have developed rapidly with the excellent photoelectric properties,the photoelectric conversion efficiency has increased from 3.8%up to 25.5%.The perovskite device structure usually formed by glass substrates,electron transport layer,perovskite layer,hole transport layer,and metal electrode.The electron transport layer plays a very important role in device,and mainly used to transport electrons and prevent the recombination of electrons and holes.An ideal electron transporting layer（ETL）of perovskite solar cells（PSCs）requires resonable energy levels,high electrical conductivity and excellent charge extraction.The low processing temperature enables ZnO a promising ETL for PSCs;however the widely used solution-processed ZnO films often suffer from high-density surface defect states,which might cause severe charge recombinations at the ETL/perovskite interface and accelarate the chemical decomposition of perovskite materials.In this work,we employed the vacuum-based magnetron sputtering method to deposit ZnO ETLs,the main research contents and results are as follows:（1）In this work,ZnO film was prepared by magnetron sputtering method and used as the electron transport layer of PSCs,the impact of the preparation process of ZnO film on the performance of PSCs was investigated.First,by adjusting the thickness of the ZnO film to explore the influence of the thickness of the ZnO film on the battery performance,so as to obtain the best preparation process of pure ZnO-based PSCs.When the sputtering time is 2 minutes and the thickness is about 50nm,the magnetron sputtered ZnO based CH₃NH₃Pb I₃PSCs yield a considerable power conversion efficiency（PCE）of 13.04%with the excellent long-term device stablity.Then compare the ZnO film prepared by magnetron sputtering method with solution method to obtain the best ZnO film preparation method.（2）Furthermore,aiming to improve the ETL/perovskite interface quality for more efficient electron extraction,a bilayer ZnO/SnO₂ETL was designed for constructing high-efficiency PSCs.The detailed morphology characterizations confirm that the bilayer ZnO/SnO₂provides low-roughness film surface for the deposition of high-quality perovskite films with full coverage and long-range continuity.The carrier dynamic study reveals that the presence of the SnO₂layer results in the formation of favorable cascade energy alignments and facilitates the electron extraction at the ETL/perovskite interface.As a result,compared with the ZnO-based PSCs,the devices constructed with the bilayer ZnO/SnO₂ETL delivers an improved PCE of15.82%.