Sumeet Mishra & Hyeonggeun Yu
Materials Science & Engineering
NC State University
Actuation Behavior of Elastomer Films Containing Chained Magnetic Nanoparticles
Infrared-to-visible up-conversion light-emitting photo-transistor
Location: EB1 Room 1011
Friday, February 12th 2016 - 11:00 am
Abstract for Sumeet Mishra's Talk:
Soft robots use materials that are amenable to dynamic reshaping, and encompass a broad range of material systems - in terms of both their composition and structural design. Commonly employed materials include elastomers, hydrogels, thermoplastics and their composites with other functional hard materials. These inorganic materials allow for actuation via programmed mechanical, chemical, magnetic, or electrical stimuli. Magnetic stimulus is a non-contact mode of actuation that does not require a line of sight to generate a response and can pervade the human body without severe complications, which is especially appealing for biomedical applications. Consequently, there is considerable interest in designing and understanding magnetically responsive devices and actuators. The actuation response of these polymer nanocomposites can be controlled by the arrangement of the functional nanoparticles within, which is the focus of my research. In this talk, I will briefly introduce the field of soft robotics and show that by designing the material and geometry of a simple actuator, complex 3D actuation can be obtained using magnetic fields.
Abstract for Hyeonggeun Yu's Talk:
Infrared imaging has attracted extensive research interest due to its applications in night vision, remote sensing, security, as well as biomedical imaging. Direct integration of an infrared photodetector and an organic light-emitting diode (OLED), which is called infrared-to-visible up-conversion device, potentially offers low cost, pixel-free infrared imaging. However, the external quantum efficiencies (EQEs) of these devices are very low due to the low photon-to-electron conversion efficiency of the infrared detector when integrated with an OLED. In this work, a novel high gain vertical infrared phototransistor is developed by fabricating IR-sensitized gate and a perforated metallic source electrode with EQEs up to 105%. By incorporating a phosphorescent OLED in this phototransistor, an infrared-to-visible up-conversion light-emitting phototransistor (LEPT) with a photon-to-photon conversion efficiency over 1,000% is demonstrated.