LUO Penghui, JIANG Hedong, LI Jiake, FAN Xueyun, GUO Pingchun, HUANG Liqun, SUN Jian, ZHU Hua, WANG Yanxiang

(Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China)

Abstract: In this study, a one-step method was used to prepare perovskite solar cells (PSCs) with planar structure. Sodium bromide (NaBr) was inserted in between the SnO₂ electron transport layers (ETLs) and the perovskite layer as the interface modification layer by using spin coating. The effect of concentration of the NaBr solution on performance of the PSCs was studied, while the effect mechanism of NaBr was explored. With XRD, SEM, AFM, XPS, PL, UV-Vis and J-V, morphology, structure, absorbance and photoelectric properties of the samples were systematically studied. It is found that the modification of NaBr can improve the crystallization behavior and light absorption of the perovskite, enhance the interface bonding between the SnO₂ ETLs and the perovskite layers and effectively improve the efficiency of PSCs. When the concentration of NaBr was 0.2 mol/L, the photoelectric performance of the device was optimized, with photoelectric conversion efficiency (PCE) of 16.21%, open-circuit voltage (V_OC) of 1.07 V, short-circuit current density (J_SC) of 20.22 mA/cm² and fill factor (FF) of 75.13%.

Key words: perovskite solar cells; electron transport layer; NaBr; interface modification