The active absorber layer plays a crucial role in a perovskite solar cell. Herein, we used high boiling point γ-butyrolactone (GBL) as the main solvent, Pb(SCN)₂ and dimethyl sulfoxide (DMSO) as an effective additive in the FA_0.83MA_0.17Cs_0.05PbI_(3−x)Br_x solution to improve the quality of perovskite films. The GBL will delay the crystallization speed of the perovskite, and lead to the grain growth assisted by thiocyanate. The synergistic effect of the solvent engineering and additive engineering is beneficial to the slow growth of the grain size. It is found that the addition of Pb(SCN)₂ increases Gibbs free energy barrier for the nucleation, leading to the formation of fewer nuclei, which results in a high quality of perovskite absorbers with larger grains and smoother surfaces. The synergistic effect of solvents and Pb(SCN)₂ on the morphology and photovoltaic performances is investigated. Compared to devices without the additive, the efficiency of devices with 5% Pb(SCN)₂-doped FA_0.83MA_0.17Cs_0.05PbI_(3−x)Br_x is raised to 19.01% from 15.21%. We believe this breakthrough regarding high efficiency perovskite solar cells will help for their transitions.

活性吸收层在钙钛矿太阳能电池中起着至关重要的作用。在这里，我们在FA _0.83 MA _0.17 Cs _0.05 PbI _{（3- x）} Br _x溶液中使用高沸点γ-丁内酯（GBL）作为主要溶剂，Pb（SCN）₂和二甲基亚砜（DMSO）作为有效添加剂。改善钙钛矿薄膜的质量。GBL将延迟钙钛矿的结晶速度，并在硫氰酸盐的辅助下导致晶粒长大。溶剂工程和添加剂工程的协同作用有利于晶粒尺寸的缓慢增长。发现添加Pb（SCN）₂增加了成核的吉布斯自由能垒，导致形成更少的核，从而获得了具有较大晶粒和光滑表面的高钙钛矿吸收剂。研究了溶剂和Pb（SCN）₂对形态和光电性能的协同作用。与不含添加剂的器件相比，掺有5％Pb（SCN）_2的FA _0.83 MA _0.17 Cs _0.05 PbI _{（3- x）} Br _x的器件的效率从15.21％提高到19.01％。我们相信，有关高效钙钛矿太阳能电池的突破将有助于其过渡。