Probing Microscopic Transport Processes in Organic and Hybrid Materials using Ultrafast Electron Imaging
Abstract
Organic and hybrid electronic materials are being increasingly used to make flexible electronic devices, organic LEDs, photovoltaics and photodetectors. For example, organic/inorganic hybrid halide perovskites have attracted intense research interest recently due to the rapidly increasing power conversion efficiency of photovoltaic devices based on them, now well over 20%. Microscopic transport processes play a significant role in determining the performance of devices based on organic and hybrid electronic materials. On one hand, the intriguing charge transfer processes in these materials, often mediated by excitons and polarons, need to be optimized but are challenging to characterize with existing tools with limited spatial and temporal resolutions. On the other hand, the heat transport and ion migration processes in these materials have increasingly been recognized to be critical to the long-term stability and efficiency of the devices but remain less explored. The overarching goal of the proposed research is to combine first-principles materials modeling with state-of-the-art ultrafast electron microscopy and optical spectroscopy to systematically examine the interplay of charge, heat and ion transport in organic and hybrid materials and unravel the influence of these microscopic transport processes on the physical properties of both uniform materials and device-relevant heterostructures. In particular, we will take advantage of the UCSB scanning ultrafast electron microscope (SUEM), which is a newly developed photon-pump-electron-probe technique that combines the temporal resolution of ultrafast lasers with the spatial resolution of scanning electron microscopes. Our research will provide new fundamental insights into microscopic energy transfer and conversion processes in organic and hybrid electronic materials and devices and will enable new applications of these emerging materials in energy harvesting, sensing and wearable devices that are of DoD interests. In addition to the scientific program, we will closely integrate research with education on both the undergraduate and graduate levels. Graduate and undergraduate researchers will participate in the proposed research and learn research skills in materials science, thermal physics and ultrafast optical spectroscopy and electron microscopy. Although this project will not support the tuition and stipend of graduate students, graduate and undergraduate students will be important participants and will be mentored by postdoctoral scholars and the PIs directly supported by this project. They will be trained to work with lasers, optical instruments, and electron microscopes, and will learn the theory of transport processes in solid-state materials by direct mentoring or taking part in advanced specialty courses developed by the PIs. The PIs have a track record of supporting URM researchers in STEM, having built and led vibrant and diverse research teams. We have collaborated with the UCSB California Alliance of Minority Participance (CAMP) program and UCSB Quantum Foundry Summer Intern program to have hosted five URM summer research interns in the past four years, and this collaboration will be continued.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 24, 2023
- Source ID
- W911NF2310188
Entities
People
- Bolin Liao
Organizations
- Army Contracting Command
- Office of the Secretary of Defense
- University of California, Santa Barbara