DOI: 10.1002/solr.202300499 ISSN:

Ultrathin Dimethylammonium Iodide Matrix: Suppressing Octahedral Distortion and Reconstructing Surface Ligands for Efficient CsPbI3 Quantum Dot Photovoltaics

Yinyan Xu, Pujun Niu, Lun Zhang, Ziying Wen, Mei Lyu, Ru Zhou, Jun Zhu
  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology
  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials

Inorganic CsPbI3 quantum dots (QDs) have received increasing attention for their application in new‐generation solar cells. However, their poor phase stability due to the small ionic radius of Cs and their inhomogeneous energy landscape on the QD surface during ligand exchange remain as bottlenecks for the practical application of CsPbI3 QD photovoltaics. Herein, the unfavorable octahedral distortion is effectively suppressed by riveting dimethylammonium hydroiodide (DMAI) into the lattice structure. Moreover, DMAI reconstructs the surface ligands to create an ultrathin matrix that encloses the QDs. The ultrathin DMAI matrix effectively passivates the vacancy defects and allows efficient coupling and charge transport in the QD films. As a result, the CsPbI3 QD solar cell yields an efficiency approaching 15%. In addition, the increase in the Goldschmidt tolerance factor enhances the stability of the octahedral structure, resulting in significantly improved device stability.

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