Our group explores light-matter and intermolecular interactions in organic optical and optoelectronic materials. We also develop and characterize novel naturally-derived sustainable organic materials, develop novel experimental techniques for characterization of charge and energy transfer at nanoscales, and utilize optical probes in entomology. Most recently we started exploring optomagnetoelectronic properties of 2D magnets and organic-inorganic hybrid materials.

In particular, we are interested in:

1. understanding basic physics of exciton, polariton and charge carrier dynamics in organic semiconductors
2. utilizing photophysical and electronic properties of organic molecules in manipulating optical, electronic, and magnetic properties of organic-inorganic heterojunctions
3. understanding exciton, magnon, and polariton physics in 2D magnets
4. developing novel high-performance optical materials for electronic and photonic applications and characterization techniques
5. exploring applications of molecular photophysics in interdisciplinary research such as insect behavior modification using visual signals

Experimental set-ups in our lab utilize time-resolved spectroscopy and microscopy, time-resolved and cw photoconductivity techniques, and single-molecule fluorescence microscopy. We are also superusers of the NSF-MRI-funded ultrafast laser facility that enables advanced time-resolved spectroscopy at 1.6-300 K temperatures, 0-7 T magnetic fields, and broad range of wavelengths.

Organic (opto)electronic materials have been extensively studied due to their low cost, opportunities to create solution processable devices on flexible substrates, and tunable properties. Applications of organic (opto)electronic materials include thin-film transistors, light-emitting diodes, solar cells, photorefractive devices, and many others [1]. By slight synthetic modifications or doping, it is possible to vary optical properties (such as absorption and fluorescence spectra), thermal and structural properties (such as phase transition temperatures and a type of packing in a crystallographic unit cell), and electronic properties (such as charge carrier mobility) of organic materials and therefore, tailor them for specific applications. In spite of many demonstrated and commercialized applications of organic materials, a number of issues, both fundamental and applied, remain. For example, basic physics of light-induced charge carrier generation and subsequent transport and extraction, the processes that lay foundation for most of the applications of organic optical materials, is still not completely understood. On the applied side, it is often challenging to make a series of organic thin films with exactly reproducible properties, especially if large-area devices are desired. Indeed, the dependence of the thin film structure on the fabrication methods and conditions and the relationship between the structure and optical and electronic properties of the film are not straightforward. Therefore, systematic comprehensive studies are needed to reveal the physical nature of all processes contributing to the device performance and understand structure-property relationships [2-5].

Incorporating molecules in microcavities enables strong interactions betweeen the molecular excitons and cavity photon, leading to formation of a polariton, a light-matter hybrid quasiparticle. Polaritons are part light and part matter, and thus they have fascinating properties [6,7]. They also provide additional tunability of properties and offer promises to boost performance and stability of optoelectronic devices.

References