报告题目：Engineered micro-/nanostructures andnanomaterials for flexible electronics
报告人：Dr. Xihua Wang
单位：Electrical& Computer Engineering，Universityof Alberta，Edmonton,Alberta, Canada
Abstract: In this talk, I will show my group’s recent efforts in the design andfabrication of engineered micro-/nanostructures and nanomaterials for flexibleelectronics, from stretchable optical diffusers for solar cells and LEDs to flexiblesensors for wearable technologies.
Lightmanagement techniques have made a lot of contributions to improve powerconversion efficiency, sensitivity, or brightness of optical and optoelectronicsystems. We have demonstrated flexible and stretchable optical diffusers withapplications for light management in quantum dot solar cells and organiclight-emitting diodes (OLEDs). Thedeveloped optical diffuser exhibits highly efﬁcient and broadband light diffractionindependent of incident light polarization and angle of incidence whileconcurrently being able to achieve high diffraction efﬁciencies of about 80%. Luminescentsolar concentrator has gained a lot of attention due to its potential to reducethe cost of a solar system by concentrating both direct and diffused sun light.Quantum dots are of interests for their broadband absorption abovesemiconductor bandgap and tunable Stokes-shift for minimizing the lightreabsorption in luminescent solar concentrators. Here I show the incorporationof quantum dots into the cellulose nanocrystal, an eco-friendly biopolymer, basedflexible film as a luminescent solar concentrator for solar energy harvesting.
Nanomaterial based strain andpressure sensors have been reported for wearable electronics, health monitoringdevices, and e-skin products. Aside from high sensitivity of these sensors,their stability and reproducibility are seldom investigated. Furthermore, dueto the complicated fabrication process and re-calibration issues raised inoperation, these sensors are still staying in research labs. We reported a newclass of flexible sensors – digital microelectromechanical sensors for strainand force sensing using microstructure engineering of PDMS. These digital sensorscan be engineered with various sensitivities for different applications, andshow no degradation after 10,000 times’ bending or pressing in operation. Iwill also show the triboelectric flexible touch sensors developed in my group.
Biography:Dr. Xihua wang is an Assistant Professor in the Department of Electrical andComputer Engineering at the University of Alberta, Canada, and a registeredprofessional engineer (P.Eng.) in Alberta. He works in the area ofnanomaterials and micro-/nanofabrication for photonics and flexibleelectronics, and has published 36 papers in prestigious journal with an h-indexof 18 with over 3,500 citations [Google Scholar].
Dr. Wangreceived the BSc degree in Physics from Peking (Beijing) University in 2003,and the Master and PhD degrees in Physics from Boston University in 2005 and2009, respectively. He was a Postdoctoral Fellow in Dr. Ted Sargent’s group atthe University of Toronto from 2009 to 2012. He has previously received thePhotonics Graduate Fellowship at Boston University (2006) and the OntarioPostdoctoral Fellowship at the University of Toronto (2010).