Nanoscale Interface @ Bulk Hybrid Perovskite

Hybrid perovskites like (C₄H₉NH₃)₂PbI₄ have fascinating layered crystal structure with periodic nanoscale interfaces between the inorganic {PbI₄}^2- and organic C₄H₉NH₃⁺ layers. Because of these interfaces, electron and hole are confined in atomically thin {PbI₄}^2- inorganic well layers. Therefore, these layered perovskites are considered as electronically 2D systems, irrespective of their crystallite sizes.^1,2 Importantly, the crystal structure is flexible, allowing a number of combinations of different organic cations and inorganic anions. So a rational design of the nanoscale interfaces, and hence, tunable optoelectronic properties are feasible. For example, excitonic binding energy can be controlled over an order of magnitude from a few tens of meV to a few hundreds of meV, with simple variation of composition of organic cations. An appropriate choice of chiral organic cation can induce chirality in optoelectronic properties arising from the inorganic sublattice. Furthermore, one can introduce new intermolecular chemical interactions between organic cations, resulting into completely water stable low dimensional hybrid perovskite.³ In this talk, I will discuss about how controlling nanoscale interface between organic and inorganic layers can yield interesting optical, optoelectronic and chemical properties.⁴ But note that the nanoscale properties will be discussed using millimeter sized single crystals.<br/><br/>References:<br/>1. Sheikh, T.; Shinde, A.; Mahamuni, S.; Nag, A. Possible Dual Bandgap in (C₄H₉NH₃)₂PbI₄ 2D Layered Perovskite: Single-Crystal and Exfoliated Few-Layer. <i>ACS Energy Lett.</i> <b>2018</b>, <i>3</i>, 2940.<br/>2. Sheikh, T.; Nawale, V.; Pathoor, N.; Phadnis, C.; Chowdhury, A.; Nag, A. Molecular Intercalation and Electronic Two Dimensionality in Layered Hybrid Perovskites. <i>Angew. Chem. Int. Ed.</i> <b>2020</b>, <i>59</i>, 11653.<br/>3. Sheikh, T.; Maqbool, S.; Mandal, P.; Nag, A. Introducing Intermolecular Cation-p Interactions for Water-Stable Low Dimensional Hybrid Lead Halide Perovskites. <i>Angew. Chem. Int. Ed.</i> <b>2021</b>, <i>60</i>,18265.<br/>4. Nag, A. “Plenty of Room” at the Interface of Hybrid Metal Halide Perovskite Single Crystals. <i>Nano Lett.</i> <b>2021</b>, <i>21</i>, 8529.