Presented by Zhijun Ning,
Time:10:00-11:00 a.m.,Nov 21,2013
Title: Novel colloidal quantum dot solid for solar cells application
Abstract: Colloidal quantum dot (CQD) based solar cells received great attention in recent years due to their promise for low-cost, high-efficiency photovoltaics deriving from solution-phase processibility and quantum-size-effect tunability for tandem and multijunction devices. In this presentation, the state of art study of colloidal quantum dot photovoltaics will be introduced. The content will mainly include two parts: (1) The development of solution phase halides treatment to reduce trap density, and using solid state ligand exchange to control doping type and density of the film. (2) Electrical engineering of the CQDs devices based on the improvement and understanding of the CQDs characters. Based on these efforts, the first certified efficiency of 7% was achieved for CQD photovoltaics and over 8% efficiency was realized recently.
Biography: Zhijun Ning obtained his bachelor degree from Liaoning Shihua University at 2004, and PhD degree from East China University of Science and Technology at 2009. After PhD study, he moved to Royal Institute of Technology in Sweden as a postdoctor from April 2009 to July 2011. Since July 2011, he has been working at University of Toronto as a postdoctor. His research mainly focused on the development of organic and colloidal quantum dot based optoelectronic materials and device structures design. Up to now, he has write three book chapters for Royal society of chemistry, Taylor & Francis Group, and Nova publishers respectively. 36 papers have published on professional journals including Nat. Nanotech., Adv. Mater., Angew. Chem. Int. Ed., Adv. Funct. Mater., ACS Nano., Energy & Environment Science etc. The total citation number is over 1300. He received nation hundred outstanding doctorate paper nomination at 2011, and Wenner gren postdoctoral scholarship in Sweden.
Presented by Kai Zhang,
Time:11:00-12:00 a.m.,Nov 21,2013
Title: Chemical Vapor Depositions of 2D materials and 2D heterostructures
Abstract: Two-dimensional (2D) materials got intense attentions due to their pretty electronic, thermal, optical and optoelectronic properties together with interesting physics behind them. Scalable synthesis of various 2D materials is necessary for both lab researches and industry applications. In this seminar, I will introduce my effort on the large scale growth of high quality 2D mateirals by chemical vapor depositions (CVD), including: monolayer and few-layer graphene films, monolayer and few-layer hexagonal boron nitride films using low-pressure CVD, atmosphere pressure CVD, plasma enhanced CVD, etc. Besides the CVD growth, different 2D heterostructures in either vertical or in-plane assembly or hybridization were also developed. Interesting plasmonic, optical properties and physics were observed and studied within the artificially designed 2D heterostructures.
Biography: Dr. Kai Zhang is a Postdoctoral Research Fellow in Graphene Research Center & Department of Chemistry at National University of Singapore (NUS). Dr. Zhang received his B.S. (2000) and M.S. (2004) degree from Hubei University, and Ph.D. degree (2011) from The Hong Kong Polytechnic University. Before joining NUS, Dr. Zhang worked as a Research Assistant with an attachment Programme in Department of Electrical Engineering & Computer Science at Massachusetts Institute of Technology. His current research interests are focused on Chemical Vapor depositions of novel 2D materials beyond graphene; 2D heterostructures and their optical and optoelectronic properties. Dr. Zhang has published more than 20 high-profile scientific papers and patents in conferences and journals such as Nature Communications, Nano Letters, Advanced Functional Materials, Lab on a Chip, Biosensors and Bioelectronics, Biomicrofluidics, etc.