Chlorobenzenesulfonic Potassium Salts as the Efficient Multifunctional Passivator for the Buried Interface in Regular Perovskite Solar Cells (Adv. Energy Mater. 20/2022)

Abstract

Perovskite Solar Cells In article number 2200417, Juan Zhao, Jie Zhong, and co‐workers report the use of an organic potassium salt with chlorine groups (3Cl‐BSAK) to modify the buried SnO2/perovskite interface in perovskite solar cells. A high efficiency of 24.27% and an open‐circuit voltage up to 1.191 V of modified devices are obtained with elevated stability.

Fluorinated Interfaces for Efficient and Stable Low‐Temperature Carbon‐Based CsPbI2Br Perovskite Solar Cells

“…The former is related to the absorption of transient species, [ 50 ] while the later can be attributed to the ground state bleaching and stimulated emission of the perovskite films. [ 38 ] Compared with reference sample, the PB negative peak intensity obviously decreased in KTFA modified sample, further confirming that KTFA contributes to the exciton transition and electron extraction from CsPbI 2 Br into SnO 2 . [ 51–54 ] Furthermore, the kinetic decay traces of PB negative peaks were fitted, as shown in Figure S12 and Table S6 (Supporting Information).…”

“…This will lead to the wetting interface for perovskite and reduce Gibbs free energy of heterogeneous nucleation. [ 38 ] The reduced roughness and improved wettability facilitate the uniform nucleation and crystallization of perovskite films, thus resulting in full surface coverage. [ 39 ] Then, the influence of KTFA modification on the optoelectronic properties of SnO 2 film was systematically studied.…”

Revealing Steric‐Hindrance‐Dependent Buried Interface Defect Passivation Mechanism in Efficient and Stable Perovskite Solar Cells with Mitigated Tensile Stress

“…The defects at buried interface, which originate from not only the lower surface of perovskite films, but also the upper surface of SnO 2 films, are one of the main reasons for the nonradiative recombination loss of interfacial carriers. [ 14–16 ] The rapid crystallization process would lead to the generation of a large number of defects in polycrystalline perovskite films, which usually distribute at grain boundary (GB) and interface. [ 17–19 ] These defects are usually deep level defects, which would bring about serious carrier nonradiative recombination and thus deteriorate device performance.…”

“…In addition, there are often a mass of oxygen vacancy defects on the surface of SnO 2 ETL, which would reduce its electron extraction and transport efficiencies, causing carrier nonradiative recombination and thereby decreasing device photovoltaic performance. [ 11,15,16,20 ] The residual strain induced by stress usually exists in perovskite films, which can be classified into compressive and tensile strain. The strain produced in perovskite films could be ascribed to many factors, such as coefficient of thermal expansion (CTE) difference between perovskites and charge transport materials (CTMs), lattice mismatch between perovskite film and substrate, temperature gradient, light/bias stimulation, phase transitions, and GBs.…”

“…[ 14 ] The chlorobenzenesulfonic potassium salts (3Cl‐BSAK) was employed by Zhong et al. [ 16 ] manipulate SnO 2 /perovskite buried interface, which enabled the realization of interfacial defect passivation and suppressed nonradiative recombination along with reduced hysteresis. Although remarkable advancements have been accomplished, the above reported interface molecules usually only can passivate the defects at buried interface but can not release interfacial stress.…”