(DURIP-21) TIME RESOLVED SPECTROSCOPY FOR VIBRATIONAL DYNAMICS AND IMAGING OF MATERIALS
Abstract
Understanding the photophysics of organic and organic-inorganic hybrid materials is crucial for their optoelectronic device application such as solar cells, light-emitting diodes, and spintronics. We have been using femtosecond visible transient absorption spectroscopy to study carrier dynamics in metal halide perovskites, organic semiconductors, and organic ligand protected metal nanoclusters. To further probe the vibrational dynamics and combine the temporal resolution with spatial resolution, this DURIP proposal is for the acquisition of advanced time resolved spectroscopy that includes mid-IR transient absorption spectroscopy and transient absorption microscope. The aim is to support the PI’s research in photophysics of perovskite materials funded by Air Force Office of Scientific Research (AFOSR) through Young Investigator Program (YIP). It will also offer an excellent platform for other research groups on photophysics of different organic and hybrid materials. These advanced instruments will undoubtedly broaden and accelerate the investigation on the vibrational dynamics and imaging of current and emerging organic materials. The proposed study will enhance the basic understanding of physical chemistry of organic and hybrid materials, which will aid in the development of emerging materials and their newly found properties for future Air Force applications. Ultrafast pump-probe electronic spectroscopy (UV-visible) probes the electronic transitions between delocalized orbitals. It lacks the capability of probing the site-specific information of structural change, and strong overlaps of electronic transitions may complicate the interpretation of experimental results. Femtosecond UV-vis pump mid-IR probe spectroscopy is a powerful tool to investigate ultrafast structural dynamics. Moreover, the dephasing time of vibration is typically longer than that of electronic transition, resulting in narrower IR absorption and easier data analysis. With femtosecond UV-Vis pump Mid-IR probe spectroscopy, we plan to probe ultrafast photoinduced structural and conformational dynamics of perovskites, organic semiconductors, organic ligand protected metal nanoclusters, etc. Although ultrafast time resolved spectroscopy offers the time resolution to probe the carrier dynamics, it is performed on large ensembles of molecules in solution or films, which provides no spatial information. Transient absorption microscope combines spatial resolution and temporal resolution. The function of optoelectronic materials and systems depends on photoinduced process in a short time and molecule spatial distribution. With transient absorption microscope, we can characterize the energy and charge transport over long distance in different materials including perovskites and organic semiconductors.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110192
Entities
People
- He Wang
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Miami