Research Projects

Crystal engineering has emerged as a robust and indispensable strategy for the rational design of structurally defined, stimuli-responsive organic materials (SOMs) exhibiting reversible and tunable luminescence switching, thereby enabling selective molecular recognition and integration into next-generation optoelectronic and sensing platforms. SOMs, which exhibit reversible photophysical responses to external stimuli such as mechanical stress, temperature, vapor exposure, light and heat (termed mechanochromism, thermochromism, vapochromism, and photochromism, respectively), are governed by intermolecular interactions in the solid state. These interactions, including hydrogen bonding and other noncovalent motifs, dictate the materials ability to achieve robust, multicolor-switching behaviour critical for applications in sensing, data security, memory devices, displays, and anticounterfeiting.3 The challenge in SOM development lies in the limited mechanistic understanding of structure-dependent intermolecular interactions that govern co-crystallization and photophysical behaviour. Traditional approaches struggle with predictive co-former selection and consistent modulation of solid-state properties. In contrast, luminescent organo-sulfonated Schiff base crystals, designed through crystal engineering, offer a solution by leveraging supramolecular design to systematically control stoichiometry, molecular packing, and crystal morphology. The interplay between molecular packing and excited-state dynamics in these materials optimizes AIE and TADF performance, enabling precise tuning of emission behavior critical for applications in next-generation optoelectronic devices, sensors, and display technologies. In addition, mechanistic insights are expected to unveil how precisely regulated supramolecular aggregation and restriction of intramolecular motions can be strategically employed to suppress non-radiative decay pathways, enhance spin–orbit coupling, and facilitate efficient reverse intersystem crossing (RISC), thereby enabling the rational design of next-generation materials with amplified AIE and TADF efficiencies. Thus, the development of luminescent organo-sulfonate Schiff base crystals and co-crystals, derived from strategically designed amino sulfonic acids and aldehyde precursors, offers a sophisticated solution to the longstanding challenge of controlling intermolecular interactions in solid-state organic materials. This approach not only advances the fundamental understanding of structure–property relationships but also holds significant potential for the creation of high-performance materials in optoelectronics, sensors, and smart photonic devices. The significance of this proposal lies in its innovative fusion of supramolecular chemistry and photophysics to overcome long-standing efficiency limitations in organic emitters.