Preparation And Defect Passivation Of NiO_x Hole Transport Layer In Trans-perovskite Solar Cells

Perovskite solar cells（PSCs）are currently one of the hottest research areas in the photovoltaic industry besides crystalline silicon solar cells.Since 2009,they have made tremendous progress in power conversion efficiency（PCE）,with the highest PCE currently reaching 25.73%.High-quality hole transport layers（HTL）are essential to achieve high-performance PSCs,the application and commercialization of PSCs are limited by the high preparation cost of conventional organic hole transport layer materials（HTM）,the difficulty of deposition on large-area substrates,and the potential degradation in humid and high-temperature environments.Inorganic p-type semiconductors can be used instead of these organic HTM for inverted PSCs,of which Ni Ox is a more widely used inorganic HTM,but it also suffers from problems such as relatively low intrinsic conductivity and more surface defects.This thesis focuses on the application of Ni Ox HTL in PSCs.On the one hand,a series of studies have been carried out on the flux of O2 in the RF magnetron sputtering Ni Ox film process,the annealing temperature of Ni Ox films and the thickness of Ni Ox films.On the other hand,poly[bis（4-phenyl）（2,4,6-trimethylphenyl）amine]（PTAA）passivation layers were deposited on the surface of Ni Ox films to passivate the surface defects by thermal evaporation,a more suitable deposition method for large area industrial production,the final PSCs were prepared with an area of 0.09 cm²,more specific research and results were presented below.（1）By varying the O2 flux in the sputtering atmosphere,the electrical and optical properties as well as the Ni³⁺content and other properties of the Ni Ox films were tuned,and finally the optimal device performance was achieved when the O2flux was 2 sccm,the fill factor（FF）and PCE were improved by 2.22%and 0.62%,respectively,compared to those without O2 flux.（2）By varying the annealing temperature of the Ni Ox films,the electrical properties,optical properties,and the crystallinity of the Ni Ox films and other properties were tuned,finally the optimal device performance was achieved at an annealing temperature of 200°C,compared to Ni Ox films unannealed,the short-circuit current density（Jsc）,FF and PCE were increased by 1.71 m A/cm²,7.95%and 2.81%respectively.（3）The thickness of the Ni Ox films was regulated,and the results show that the optical transmission properties of the Ni Ox films and the series resistance（Rs）of the final PSCs devices increase significantly with the increase of the Ni Ox films thickness,leading to the decrease of the parameters of the PSCs devices,and finally the optimal device performance was achieved at the Ni Ox films thickness of 10 nm.（4）The PTAA passivation layers were deposited on the Ni Ox films by thermal evaporation,and the final results showed that the PTAA passivation layers deposited by thermal evaporation effectively passivated the defects on the surface of the Ni Ox films and enhanced the hole extraction capability of the Ni Ox films,which improved the open circuit voltage（Voc）,Jsc and PCE by 0.03 V,0.58 m A/cm² and 0.53%,respectively,compared with the PSCs devices without the PTAA passivation layers.