Piezo-phototronics of the third generationsemiconductors
王中林
中国科学院北京纳米能源与系统研究所，所长
-------演讲摘要-------
The first generation semiconductors (Si, Ge) and the second generationsemiconductors (GaAs) have a common characteristic: their crystal structuresare cubic, so that they have little piezoelectric effect. However, for thethird generation semiconductors, such as GaN. SiC and ZnO, they have thehexagonal crystal structure, which means that they have unique piezoelectriceffect. Due to the polarization of ions in a crystal that has non-centralsymmetry once subject to a mechanical strain, a piezoelectric potential (piezopotential) is created in thecrystal. Electronics fabricated by using inner-crystal piezopotential as a“gate” voltage to tune/control the charge transport behavior is named piezotronics, with applications instrain/force/pressure triggered/controlled electronic devices, sensors andlogic units. Using the piezoelectric polarization charges at the pn junction to control charge carrier separationor combination process in optoelectronics is called the piezo-phototroniceffect. This talk will focus on how to use piezo-phototronic effect to tune theefficiency of LED lighting and solar cells.
---------------------个人简介 ---------------------
王中林院士，中国科学院北京纳米能源与系统研究所所长，佐治亚理工学院终身校董事讲席教授。王教授是2022年Nano Research Award,2019年爱因斯坦世界科学奖(Albert EinsteinWorld Award of Science)、2018年埃尼奖 (ENI award –The “Nobel prize”for Energy)、2015年汤森路透引文桂冠奖、2014年美国物理学会James C. McGroddy新材料奖、2013年中华人民共和国国际科技合作奖，和2011年美国材料学会奖章(MRSMedal)等国际大奖得主。他是中科院外籍院士、美国国家发明家科学院院士，欧洲科学院院士、加拿大工程院外籍院士，美国国家发明家科学院院士，国际纳米能源领域著名刊物Nano Energy（最新IF：19.08）的创刊主编和现任主编。
Efficient single-layer blue organic light-emitting
diodes
Paul W.M. Blom
德国马普高分子所, 所长/教授
-------演讲摘要-------
Efficient organic light-emitting diodes (OLEDs) commonly comprise a multilayer stack including charge-transport and charge- and exciton-blocking layers, to ensure charge recombination within the emissive layer. Here, we demonstrate a highly simplified single-layer blue-emitting OLED based on thermally activated delayed fluorescence with the emitting layer simply sandwiched between Ohmic contacts consisting of a polymeric conducting anode and a metal cathode. Thesingle-layer OLED exhibits an external quantum efficiency of 27.7% with minorroll-off at high brightness. The internal quantum efficiency approaches unity,demonstrating that highly simplified single-layer OLEDs can achieve state-of-the-artperformance, while greatly reducing the complexity of the design, fabrication,and device analysis.
---------------------个人简介 ---------------------
Paul W.M. Blom,born in 1965 in The Netherlands, received his Ph. D. Degree in1992 from the Technical University Eindhoven on picosecond charge carrierdynamics in GaAs. At Philips Research Laboratories he was engaged in theelectro-optical properties of polymer light-emitting diodes. From 2000 he helda professorship at the University ofGroningen in the field of electrical and optical properties of organicsemiconducting devices. In September 2008 he became Scientific Director of theHolst Centre in Eindhoven, where the focus is on foil-based electronics,followed in 2012 by an appointment as director at the MPI for polymer researchin the field of molecular electronics. He is named among the World's MostInfluential Minds and the Top 1% Highly Cited Researchers in Materials Scienceby Thomson Reuters.
