1. Angew: 23.18%@1.67 eV record efficiency, hydrogen-bonded polymer for efficient and stable perovskite and its silicon stack photovoltaics
The pursuit of efficient and stable wide bandgap (WBG) perovskite solar cells (PSCs ), especially monolithic perovskite/silicon tandem devices, is a key focus to achieve commercialization of perovskite photovoltaics. Liu Shengzhong and Wang Kai of Dalian Institute of Chemical Physics, Miao Qingqing of Institute of Process Engineering, Chinese Academy of Sciences, and Dongdong Li of Zhangjiang Laboratory designed poly(ionic liquids) (PIL) with different alkyl chain lengths based on density functional theory calculations. The results show that PILs with longer alkyl chain lengths tend to exhibit stronger binding energy to perovskite structures.
Next, the researchers synthesized PIL to create a hydrophobic hydrogen-bonded polymer network (HHPN), which passivates the WBG perovskite/electron transport layer interface, inhibits ion migration, and serves as a barrier layer against water and oxygen intrusion. Therefore, HHPN effectively suppresses non-radiative recombination losses while promoting efficient carrier transport, thereby significantly improving open circuit voltage (VOC) and fill factor.
As a result, the optimized single-junction WBG PSC achieved an efficiency of 23.18% with a VOC as high as 1.25 V, which is the highest efficiency reported for a WBG (over 1.67 eV) PSC. These devices also exhibit excellent heat and moisture resistance. Notably, this versatile strategy can be extended to textured perovskite/silicon tandem cells, achieving 28.24% efficiency while maintaining excellent operational stability.
2. AEM: nearly 20% efficiency! Iodine-rich inorganic perovskite solar cells
The presence of excess PbI in the perovskite film negatively affects its long-term stability. Liu Shengzhong and Wang Kai of the Chinese Academy of Sciences and Wang Kang of the Northern University for Nationalities proposed an interphase modification ( IPM ) strategy to eliminate residual PbI 2 to improve the quality of inorganic CsPbI 3- type perovskite films, in which exogenous sources were introduced Chemical reagents are used to treat the mesophase.
By converting residual PbI into a new 1D perovskite phase, the IPM strategy acts as a patch to stitch grain boundaries in inorganic perovskite films . In addition, the IPM strategy not only improves the quality of the perovskite film, but also alleviates energy disorder, reduces trap state density, and extends carrier lifetime by accelerating the mesophase transformation process and passivating surface defects.
As a result, the authors obtained a perovskite solar cell ( PSC ) with ≈20 % efficiency and 83.3% fill factor, and its excellent stability even after being exposed to air for 3000 hours without any encapsulation .
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