A nice TEDtalk as our ESL practice activity… Enjoy!
Joseph DeSimone is a scholar, inventor and serial entrepreneur. A longtime professor at UNC-Chapel Hill, he’s taken leave to become the CEO at Carbon3D, the Silicon Valley 3D printing company he co-founded in 2013. DeSimone, an innovative polymer chemist, has made breakthrough contributions in fluoropolymer synthesis, colloid science, nano-biomaterials, green chemistry and most recently 3D printing. His company’s Continuous Liquid Interface Production (CLIP) suggests a breakthrough way to make 3D parts.
What we think of as 3D printing, says Joseph DeSimone, is really just 2D printing over and over … slowly. Onstage at TED2015, he unveils a bold new technique — inspired, yes, by Terminator 2 — that’s 25 to 100 times faster, and creates smooth, strong parts. Could it finally help to fulfill the tremendous promise of 3D printing?
By Susanta Banerjee Overview Fluoropolymers are used in applications demanding service at enhanced temperature while maintaining their structural integrity and have excellent combination of chemical, physical and mechanical properties. Advancements in materials and processing technology mean that a huge amount of research is currently taking place into new, high performance applications for…
By Tsuyoshi Nakajima, Henri Groult Overview Advanced Fluoride-Based Materials for Energy Conversion provides thorough and applied information on new fluorinated materials for chemical energy devices, exploring the electrochemical properties and behavior of fluorinated materials in lithium ion and sodium ion batteries, fluoropolymers in fuel cells, and fluorinated carbon in capacitors, while also…
[ Authors ]
K. Prabha Rajeev, C. Opoku, V. Stolojan, M. Constantinou, F. Meyer, L. Chen, M. Shkunov
[ Abstract ]
Silicon nanowires (Si NW) are ideal candidates for solution processable field effect transistors (FETs). The interface between the Si NW and the dielectric plays a crucial role in the FET performance, and it can be responsible for unwanted effects such as hysteresis of the I-V characteristics caused by the transistor threshold voltage shift when the gate voltage is applied. Using gate-voltage bias stress measurements and sweep-rate studies we show that a significant hysteresis of up to 40V in Si NW FETs with SiO2 dielectric is mainly due to the hole traps at the nanowire/SiO2 interface. We demonstrate a method for reducing hysteresis to only 2.5V by replacing SiO2 with a solution processable fluoropolymer dielectric Cytop. Finally, we demonstrate that nanowire surface trap density is dictated by the dielectric, by fabricating double gate FETs with bottom SiO2 and top Cytop gate insulators, where nanowire/SiO2 interface shows an order of magnitude higher trap density (1x10^13cm-2) compared to nanowire/fluoropolymer interface traps (7.5x10^11cm-2).