Project Description:

Moiré superlattices of two-dimensional (2D) graphene and transition metal dichalcogenides (TMDCs) with hexagonal lattices have recently emerged as a programmable solid-state platform for strongly correlated and topological quantum phenomena. 2D organic-inorganic halide perovskites with extraordinary optical and electronic properties are excellent candidates for creating moiré structures featuring tetragonal lattices. Moiré flat bands have been predicted in twisted 2D perovskites; however, their experimental realization has been inhibited by a variety of synthetic and fabrication challenges, including difficulties in creating ultra-thin perovskite sheets free from bulky organic ligands, and in transferring and stacking of these thin sheets that have weak ionic lattices. In this project, we will demonstrate a new square symmetry of moiré superlattices with ligand-free 2D hybrid perovskites by stacking two layers of ultrathin 2D perovskite sheets that are synthesized in our lab. Moiré superlattices will be characterized directly through high-resolution transmission electron microscopy. Electronic and exciton transport properties will be examined using advanced optical characterizations. Meanwhile, state-of-the-art first-principle calculations will be performed to understand the electronic structures of the twisted perovskite moirés. This project will lead to a new tunable family of 2D semiconducting materials for exploring moiré flat band physics.

Start Date:

June 2023

Postdoc Qualifications:

PhD in chemistry, physics, materials science, chemical engineering, or related fields. Hand-on experience with materials synthesis, optical characterizations, and DFT.

Co-Advisors:

Letian Dou (Chemical Engineering)
Arun Mannodi Kanakkithodi (Materials Engineering)

Bibliography:

Akriti, Enzheng Shi, Stephen B. Shiring, Jiaqi Yang, Cindy L. Atencio-Martinez, Biao Yuan, Xiangchen Hu, Yao Gao, Blake P. Finkenauer, Alan J. Pistone, Yi Yu, Peilin Liao, Brett M. Savoie, Letian Dou; “Layer-by-Layer Anionic Diffusion in Two-Dimensional Halide Perovskite Vertical Heterostructures”, Nature Nanotechnology 2021, 16, 584-591.

Enzheng Shi, Biao Yuan, Stephen B. Shiring, Yao Gao, Akriti, Yunfan Guo, Cong Su, Minliang Lai, Peidong Yang, Jing Kong, Brett M. Savoie, Yi Yu, Letian Dou; “Two-dimensional halide perovskite lateral epitaxial heterostructures”, Nature 2020, 580, 614-620.

Arun Mannodi-Kanakkithodi, Maria KY Chan; “Data-driven design of novel halide perovskite alloys”, Energy & Environmental Science 2022, 15, 1930-1949.

Duyen H. Cao, Peijun Guo, Arun Mannodi-Kanakkithodi, Gary P. Wiederrecht, David J. Gosztola, Nari Jeon, Richard D. Schaller, Maria K. Y. Chan, and Alex B. F. Martinson, “Charge Transfer Dynamics of Phase-Segregated Halide Perovskites: CH3NH3PbCl3 and CH3NH3PbI3 or (C4H9NH3)2(CH3NH3)n−1PbnI3n+1 Mixtures”, ACS Appl. Mater. Interfaces. 2019, 11, 9, 9583–9593.

Benjamin T. Diroll, Arun Mannodi-Kanakkithodi, Maria K. Y. Chan, and Richard D. Schaller , “Spectroscopic Comparison of Thermal Transport at Organic–Inorganic and Organic-Hybrid Interfaces Using CsPbBr3 and FAPbBr3 (FA = Formamidinium) Perovskite Nanocrystals, Nano Lett. 2019, 19, 11, 8155–8160.