Solar energy is a crucial alternative source of power that scientists and engineers worldwide are striving to improve. In search of higher conversion efficiency and increased stability of solar cells, researchers from the Hefei Institutes of Physical Science (HFIPS) at the Chinese Academy of Sciences have proposed an innovative method of fabricating homogenized perovskite films. Their groundbreaking study, published in Nature, explores the inhibition of phase segregation caused by internal cation inhomogeneity, leading to a remarkable increase in conversion efficiency to 26.1%. This advancement ties the existing record and offers promising insights into the future of solar cell technology.
Lead-halide perovskite solar cells (PSCs) have garnered significant attention due to their notable efficiency. However, these cells experience a slowdown in conversion efficiency growth over time. Previous studies primarily focused on the surface, dopant, and component levels, leaving the phase level relatively unexplored. Recognizing this limitation, Pan Xu and his team decided to investigate the phase segregation occurring within perovskite films, which directly impacts both the efficiency and stability of the cells.
Through meticulous experimental approaches, the researchers quantified the vertical distribution of cations FA+ and Cs+ within perovskite films. Their findings revealed an intriguing pattern: Cs+ tended to aggregate at the bottom of the film, while a significant amount of FA+ gathered at the upper interface. These results were further confirmed by studying the distribution in the crystalline phase. The team’s rigorous experiments successfully unveiled the out-of-plane inhomogeneous distribution in a laboratory setting, marking a significant scientific achievement.
With a clear understanding of the cation distribution, the researchers delved into unraveling the underlying reasons behind this phenomenon. Through in-situ testing, they determined that cations in different groups crystallize and transform at distinct rates. This discrepancy in crystallization and phase transition rates was identified as the cause of the observed inhomogeneity. Armed with this knowledge, the team devised a strategic solution using 1-(Phenylsulfonyl)pyrrole (PSP) as an additive. This mode of intervention aimed to address the crystallization and phase transition discrepancies, ultimately leading to the production of homogeneous films.
The researchers were thrilled to witness a substantial increase in conversion efficiency to 25.8% after implementing their proposed strategy. The homogenized perovskite films displayed impressive long-term stability, with a conversion efficiency retention rate of 92% after 2,500 hours of maximum power point tracking. This achievement ties the current record in conversion efficiency. Pan Xu and his team’s innovative work in phase optimization for solar cells paints a promising technological path towards achieving higher conversion efficiency and improved stability.
The study conducted by the researchers at the Hefei Institutes of Physical Science presents a groundbreaking approach to fabricating homogenized perovskite films for solar cells. By tackling the issue of phase segregation caused by internal cation inhomogeneity, the team effectively enhanced the conversion efficiency and stability of solar cells. Their findings offer valuable insights into potential strategies for elevating the performance of solar energy technologies. With continued research and development, these advancements hold great promise for a greener and more sustainable future powered by solar energy.
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