Introduction of γ-butyrolactone (GBL) solvent to assist perovskite crystallization and develop stable and efficient perovskite solar cells

Abstract

Researchers' admiration for perovskite materials and their efforts to develop of perovskite-based photovoltaics every day make the world near to the industrialization of perovskite solar cells (PSCs). Interface engineering, which as a practical and effective approach to tailor the interface of perovskite and Hole transport layer (HTL) has been introduced to fabricate efficient and stable PSCs, herein is employed through the addition of γ-butyrolactone (GBL) into the anti-solvent solution. Since, the GBL solvent was added into the chlorobenzene (CBZ) as anti-solvent, in different volume ratios to improve crystallization of perovskite layer, and brings us a simple interface engineering at perovskite/HTL. Results showed with the addition of GBL into the CB anti-solvent a perovskite layer with fewer pinholes is achieved. The anti-solvent engineering enlarged perovskite grain sizes and passivated grain boundaries. It was observed that our approach, reduced carriers' traps in the perovskite film and charge inhibit recombination processes within PSCs. The boosted crystalline properties of the treated perovskite layer, the facilitated charges extraction at perovskite/HTL interface and the reduce charge accumulation brings a champion efficiency of 18.97% for the modified devices higher than that of 15.21% for the unmodified devices. In addition, due to the boosted hydrophobic property of the modified perovskite layer, the stability behavior of the related PSCs improved.