A research team headed by Prof. You Jingbi from the Institute of Semiconductors at the Chinese Academy of Sciences has made a significant breakthrough in the realm of perovskite solar cells. In traditional perovskite thin films, an uneven distribution of chlorine in the vertical direction has posed a barrier to enhancing both the efficiency and stability of the cells. To tackle this issue, the team introduced a strategy aimed at achieving a homogeneous vertical distribution of chlorine (HVCD). By incorporating alkali metal oxalate, they effectively curbed the migration of chlorine elements, thereby successfully fabricating high-quality perovskite semiconductor thin films. The prototype perovskite solar cell device, developed using this thin film, attained a remarkable photoelectric conversion efficiency of 27.2%. Moreover, it has received certification from authoritative bodies, confirming its stable operation under various conditions. This research has led to a concurrent improvement in both efficiency and stability, offering substantial backing for the industrial advancement of perovskite solar cells. The pertinent findings have been published in the esteemed journal Science.