DOI: https://doi.org/10.29363/nanoge.incnc.2021.028
Publication date: 8th June 2021
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. So for solar cell and photocatalytic applications, one can choose the composition with lower excitonic binding energies, whereas for LED, higher excitonic binding energy is preferred. Interestingly, chiral organic cations can impart optical non-linearity and chiral optoelectronic properties. In this talk, I will discuss about how controlling nanoscale interface between organic and inorganic layers can yield interesting optical and optoelectronic properties.3 But note that the nanoscale properties will be discussed using millimeter sized single crystals.