Improved Thermal Stability and Film Uniformity of Halide Perovskite by Confinement Effect brought by Polymer Chains of Polyvinyl Pyrrolidone

Shuyue Wu, Siyuan Lin, Zhiqiang Shi, De'en Guo, Han Huang, Xuefan Zhou, Dou Zhang, Kechao Zhou, Wenhao Zhang, Yue Hu, Conghua Zhou*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Polyvinyl pyrrolidone (PVP) is doped to PbI2 and organic salt during two-step growth of halideperovskite. It is observed that PVP molecules can interact with both PbI2 and organic salt, reduce the aggregation and crystallization of the two, and then slow down the coarsening rate of perovskite. As doping concentration increases from 0 to 1 mM in organic salt, average crystallite size of perovskite decreases monotonously from 90 to 34 nm; Surface fluctuation reduces from 259.9 to 179.8 nm at first, and then increases; Similarly, surface roughness decreases from 45.55 to 26.64 nm at first, and then rises. Accordingly, a kind of “confinement effect” is resolved to crystallite growth and surface fluctuation/roughness, which helps to build compact and uniform perovskite film. Density of trap states (t-DOS) is cut down by ≈60% at moderate doping (0.2 mM). Due to the “confinement effect”, power conversion efficiency of perovskite solar cells is improved from 19.46 (±2.80) % to 21.50 (±0.99) %, and further improved to 24.11% after surface modification. Meanwhile, “confinement effect” strengthens crystallite/grain boundaries and improves thermal stability of both film and device. T80 of device increases to 120 h, compared to 50 h for reference ones.

Original languageEnglish
JournalSmall
Early online date17 Mar 2023
DOIs
Publication statusE-pub ahead of print - 17 Mar 2023

Keywords / Materials (for Non-textual outputs)

  • confinement effect
  • perovskite
  • polyvinyl pyrrolidone (PVP)
  • stability
  • thermal

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