One of the potential photovoltaic possibilities for generating renewable energy is organometallic perovskite-based solar cell. However, the presence of grain boundaries and defects in the bulk or interfacial sites of perovskites prevents future device efficiency increases. In this work, a green EA solvent was utilized to enhance the crystallization of triple-cation perovskite polycrystals, enlarge the perovskite grain size, and minimize the density of trap states, resulting in high-quality films. Under AM 1.5G irradiation, perovskite solar cell with an efficiency of 18.63% and a fill factor of 79.78% were obtained. This photovoltaic outperformed standard cells in terms of efficiency, stability, and reproducibility, which was attributable to the high-quality perovskite merits. The environmental and thermal stabilities of unsealed cells are also improved, with only 8% and 9% degradation of the original efficiency after storage for 50 days and 350 hours in environment (50% RH) and thermal (80 °C) conditions, respectively. Our research established a simple and practical method for developing photovoltaic cells with good stability and high efficiency for commercialization.