The hybrid perovskite CH3NH3PbX3 (X= Cl, Br, I) is a promising material for developing novel optoelectronic devices. Owing to the intrinsic non-layer structure, it remains challenging to synthesize molecularly thin CH3NH3PbX3 with large size. Here, we report a low-cost and highly efficient fabrication route to obtain large-scale single-crystalline 2D CH3NH3PbX3 perovskites on a mica substrate via liquid epitaxy. The 2D perovskite is characterized as 8 nm in thickness and hundreds of micrometers in lateral size. First-principles calculations suggest the strong potassium-halogen interactions at the perovskite/mica interface lower the interface energy of perovskites, driving their fast in-plane growth. Spectroscopic investigations reveal 2D CH3NH3PbBr3 possess small exciton binding energy of 30 meV, allowing a superior visible-light photodetector with a photoresponsivity of 126 A/W and a bandwidth exceeded 80 kHz. These features demonstrate that liquid epitaxy is a bottom-up approach to fabricate the non-layer structured 2D perovskites, which offer a new material platform for the device applications and fundamental investigations.
@article{arxiv.1811.03418,
title = {Liquid Epitaxial Growth of Two-dimensional Non-layer structured hybrid Perovskite},
author = {Yu Bai and Haixin Zhang and Mingjing Zhang and Di Wang and Hui Zeng and Hao Xue and Guozheng Wu and Ying Xie and Yuxia Zhang and Hao Jing and Jing Su and Haohai Yu and Zhanggui Hu and Ruwen Peng and Mu Wang and Yicheng Wu},
journal= {arXiv preprint arXiv:1811.03418},
year = {2018}
}