Advanced organic and hybrid electronic devices for high-resolution Hall effect and photocurrent spectroscopy.

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Non-technical:This research project focuses on the working principles of transistors and photo-detectors based on two classes of novel materials. Organic semiconductors and organic-inorganic hybrid perovskites are promising materials for applications in solar cells, flexible electronics, sensors and actuators. High-purity single crystals of these materials are expected to conduct charge efficiently, have long charge carrier lifetimes, and tolerate defects. All of these properties are attractive for future applications in optoelectronics. The research team will characterize electrical conduction with high-precision of organic and perovskite devices under various external stimuli. Stimuli include calibrated mechanical strain, performed by bending flexible devices, illumination with visible light and varied temperature. These studies will yield a better understanding of the unique properties of these novel materials and behavior of devices based on them. The project will boost the development of flexible transistors and photo-detectors and yield powerful methods to characterize these devices. This project will give students an opportunity to perform research on emerging electronic materials. Aspiring researchers will learn semiconductor science, acquire modern research skills and prepare for careers in science and technology.Technical:Novel electronic devices based on emergent highly crystalline organic semiconductors and perovskite materials are under intense research for their potential use in the next-generation optoelectronic applications. The main focus of this project is to significantly advance the fundamental understanding of operating principles and microscopic mechanisms governing the behavior of organic field-effect transistors and perovskite photo-conductors. The research team plans to achieve this by employing a unique and powerful combination of high-resolution ac-Hall effect measurements, an in-situ application of calibrated uniaxial mechanical strains, variable temperature and/or photoexcitation, as well as using complementary theoretical modeling in order to understand the intrinsic (trap-free) charge carrier mobilities, electron-hole recombination rates, carrier lifetimes and diffusion lengths in these devices. Implementation of the project is expected to result in the development of high-performance, flexible organic field-effect transistors based ultra-thin organic crystals and optimized perovskite photo-conductors with chemically passivated surfaces, lead to new methodologies of high-precision Hall effect measurements, especially important for emergent ?soft? and flexible electronics, and more broadly contribute to a better understanding of the electronic, photonic and magneto-transport properties of novel semiconductor devices. The interdisciplinary nature of this project provides excellent educational, human resource and outreach opportunities in the area of optoelectronics and semiconductor device engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.