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Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite.

  • Author(s): Lee, Jin-Wook
  • Tan, Shaun
  • Han, Tae-Hee
  • Wang, Rui
  • Zhang, Lizhi
  • Park, Changwon
  • Yoon, Mina
  • Choi, Chungseok
  • Xu, Mingjie
  • Liao, Michael E
  • Lee, Sung-Joon
  • Nuryyeva, Selbi
  • Zhu, Chenhui
  • Huynh, Kenny
  • Goorsky, Mark S
  • Huang, Yu
  • Pan, Xiaoqing
  • Yang, Yang
  • et al.
Abstract

Conventional epitaxy of semiconductor films requires a compatible single crystalline substrate and precisely controlled growth conditions, which limit the price competitiveness and versatility of the process. We demonstrate substrate-tolerant nano-heteroepitaxy (NHE) of high-quality formamidinium-lead-tri-iodide (FAPbI3) perovskite films. The layered perovskite templates the solid-state phase conversion of FAPbI3 from its hexagonal non-perovskite phase to the cubic perovskite polymorph, where the growth kinetics are controlled by a synergistic effect between strain and entropy. The slow heteroepitaxial crystal growth enlarged the perovskite crystals by 10-fold with a reduced defect density and strong preferred orientation. This NHE is readily applicable to various substrates used for devices. The proof-of-concept solar cell and light-emitting diode devices based on the NHE-FAPbI3 showed efficiencies and stabilities superior to those of devices fabricated without NHE.

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