Chirality, Stability and Optoelectronics from Nanoscale Interface of Hybrid Perovskites

Colloidal nanocrystals show surface-related phenomena owing to the small size of the crystal. In difference, hybrid perovskites like (C₄H₉NH₃)₂PbI₄ have layered crystal structure with periodic nanoscale interfaces between the inorganic {PbI₄}^2- and organic C₄H₉NH₃⁺ layers. Chemical compositions of such nanoscale interfaces can be designed in numerous ways yielding novel functionalities.^1-2 For example, chirality can be induced from the organic sublattice to the inorganic one through such nanoscale interfaces. Consequently, the optical and optoelectronic properties, that mainly contributed by the inorganic sublattice, also attains chirality.³ In this talk, I will discuss about the composition-structure-chiroptic property relationships in a series of chiral 2D, 1D, and 0D hybrid perovskite derivative systems. The non-centrosymmetric crystal structure also leads to reasonably strong optical nonlinearity and has potential for bulk photovoltaics. I will also discuss about how non-covalent interactions (cation-p or halogen-halogen) can make such low-dimensional hybrid metal halides completely water-stable for years.^4-5 It is to be noted here that the nanoscale physical and chemical properties mentioned here is governed by low-dimensional crystal structure of the hybrid system, and not by the size of the crystal.<br/> <br/>1. Sheikh, T.; Nawale, V.; Pathoor, N.; Phadnis, C.; Chowdhury, A.; Nag, A. <i>Angew. Chem. Int. Ed.</i> <b>2020</b>, <i>59</i>, 11653.<br/>2. 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.<br/>3. Sheikh, T.; Maqbool, S.; Rajput, P. R.; Mandal, P.; Nag, A. Effect of Chirality on the Optical Properties of Layered Hybrid Perovskite R- and S-a-methylbenzylammonium lead iodide. <i>Chem. Commun.</i> <b>2022</b>, <i>58</i>, 7650.<br/>4. 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/>5. Chakraborty, R.; Sheikh, T.; Nag, A. Iodine–Iodine Interactions Suppressing Phase Transitions of 2D Layered Hybrid (I-(CH₂)<i>_n</i>-NH₃)₂PbI₄ (<i>n</i> = 2–6) Perovskites. <i>Chem. Mater.</i> <b>2022</b>, <i>34</i>, 288.