FlexibleElectronics with NanoManufacturing

　　 半导体材料作为信息科学技术物质基础的主体，半个多世纪来发挥着巨大的作用，随着信息科学技术的迅猛发展，推动着信息光电技术向可再生、超快响应、超高容量和高集成度方向发展；近年来随着能源危机的凸显和环保意识的普及，对发展高效光电、电光转换半导体材料的需求日益迫切，对半导体材料及相关器件的制造过程提出了简化工艺、降低能耗等方面的要求。但现有半导体材料已难以胜任。20世纪80年代发展起来的有机/无机复合半导体材料通过结构复合、功能复合而兼具了有机材料的设计多样性、柔性、易加工性和无机材料的高载流子迁移率、高稳定性的优点，并往往产生协同优化效应，是一类含有两种及两种以上有机和无机组分并具有半导体性质的新型复合功能材料，成为信息和能源未来发展的关键材料之一。而由复合带来的新现象、新结构、新效应等一系列新的科学问题亟待解决，以推动材料科学自身的发展。有机/无机复合半导体材料的研究具有大跨度的多学科交叉特点，是材料科学中最活跃、最具创新潜力和发展空间的研究方向之一，有很强的前瞻性，属于《国家中长期科学和技术发展规划纲要（2006～2020年）》和《国家自然科学基金“十一五”发展规划》中优先发展的信息、能源和新材料领域。
　　一、科学目标
　　在有机/无机复合半导体材料的复合原理、复合界面结构与特性、光电转换过程、载流子在有机/无机复合材料中的传输机理和结构稳定化等相关理论问题上有重要创新，注重有机/无机复合而产生的新现象、新结构、新效应的发现；在有机/无机复合半导体材料的高载流子迁移率的实现途径与低成本可控制备等关键技术上有重大突破，注重新原理、新功能、新机制的探索；在具有重大应用背景的薄膜晶体管、非染料敏化型薄膜太阳能电池等方面获得处于世界领先水平的创新成果。
　　二、研究内容
　　1．有机/无机复合半导体材料的设计与结构可控的简易制备加工
　　研究设计、制备过程中材料微结构的调控，鼓励引入创新性的复合手段及简易制备与加工方法。
　　2．有机/无机复合半导体材料的表面与界面性质研究
　　结合理论计算模拟，研究复合体系表面与界面结构与特性、光电转换过程，以及载流子在不同界面、界面过渡层及体相中的注入、输运规律等等。
　　3．有机/无机复合半导体材料结构稳定性研究
　　研究有机/无机复合半导体材料在光、热等外场作用下结构的演化与控制以及稳定化途径。
　　4．高载流子迁移率的有机/无机复合半导体材料的研究
　　研究有机/无机复合半导体材料结构与载流子长程输运性能的关系以及高载流子迁移率的实现途径。注重新原理、新功能、新机制的探索。
　　5．有机/无机复合半导体器件的设计与制备
　　研究有机/无机复合半导体材料薄膜的形态结构和器件性能之间的关系、探明其工作原理以及器件设计与制造的主要工艺。鼓励研究材料与器件一体化的设计与制造。
　　三、申请注意事项
　　申请书的资助类别选择“重大项目”，亚类说明选择“项目申请书”或“课题申请书”，附注说明选择“有机/无机复合半导体材料的基础研究”。
　　“项目申请书”中的“主要参与者”只填写各课题“申请人”相关信息；“签字和盖章页”中“项目依托单位公章”盖“项目申请人”所属依托单位公章，“课题依托单位公章”盖“课题申请人”所属依托单位公章。
　　“课题申请书”的“主要参与者”包括课题所有主要成员相关信息；“签字和盖章页”中“课题依托单位公章”盖“课题申请人”所属依托单位公章，“合作单位公章”盖合作单位公章。
　　“项目申请书”和“课题申请书”应通过各自的依托单位提交。
　　本项目由工程与材料科学部、化学科学部、信息科学部和数理科学部联合提出，由工程与材料科学部负责组织评审。

By Phil Berardelli
ScienceNOW Daily News
7 August 2008

Chock-full of transistors, the average circuit board is a rigid and delicate thing. Such stiff circuit boards are fine for computers and other large, stationary devices. But engineers are pushing to weave electronics into the objects all around us--including our clothes--and doing that requires flexible circuits. Some circuit boards can bend, but they don't twist or stretch. Now, a Japanese team has produced a rubbery, stretchy conducting material--the first step toward building a flexible circuit.
To do it, Takao Someya, an electronics engineer at the University of Tokyo, and his team mixed tiny tubes of carbon known as nanotubes with a polymer. The nanotubes carry the electricity, and the polymer provides the flexibility. To get the technique to work, the researchers had to overcome several obstacles. For example, the nanotubes attract one another so strongly that it's difficult to keep them from clumping.
So first, Someya and colleagues made the carbon nanotubes much less mutually attractive by mixing them into a substance called an ionic liquid. The treatment turns the nanotubes into a black, pasty concoction the researchers call bucky gel. (The molecular structure of nanotubes resembles the famous geodesic domes designed by Buckminster Fuller.) Next, they mixed the bucky gel with a rubberlike substance called a fluorinated copolymer and poured the mixture onto a glass plate. Last, Someya's team coated the substance with silicone rubber and punched tiny holes all over the matrix to increase its flexibility.
The resulting material looks a bit like a woman's nylon stocking, and Someya says it can be stretched by up to 38% of its original length without loss of conductivity because enough of the nanotubes stay in contact to continue to carry electricity. That's nearly four times more elastic than any other conducting substance, he says, and about 100 times more conductive than any other known elastic material. And that's just the prototype. "We believe there is much room for further improvement in elastic conductors," he says.
It's an important finding, says materials scientist John Rogers of the University of Illinois, Urbana-Champaign. For example, he says, any attempt to integrate electronics with the human body requires flexibility that doesn't hinder movement, and this can't be achieved with conventional devices. "Fully stretchable electronics is the best option for this broad area," Rogers says. Possible applications for the technology include large, stretchable video displays, artificial skin, and electronic books in Braille for the blind.
http://sciencenow.sciencemag.org/cgi/content/full/2008/807/2

PORTLAND, Ore. — Nano-inks for aerosol printing of electronics circuitry are being jointly developed by Applied Nanotech Inc. and Optomec for its M3D aerosol jet printer.
Optomec's jet printer transfers metallic, semiconducting and insulating inks onto any shaped substrate. Aerosol Jet printing like ink-jet printing can reproduce electronic circuits on inexpensive flexible polymer films.
Optomec's printer is designed for rapid prototyping of new devices and short production runs, but printable electronics is also poised to debut in consumer electronics devices later this year, according to IDTechEx Ltd. (Cambridge, Mass.) Printed electronics applications include patterning circuit boards, solar panels, on-battery testers, RFID tags, interconnection planes and other flexible electronics.
Most ink-jet printing is currently done with silver inks, which are expensive compared to copper nano-inks announced by Applied Nanotech (Austin, Texas) and Optomec (Albuquerque, N.M.). Current copper inks copper flakes over 250 nanometers in size, requiring 424-degree F annealing. Applied Nanotech said its copper nanoparticles 10 to 20 nanometers and can be deposited at annealing temperatures below 212 degrees F.
The Optomec printer's minimum feature size of 10 microns prompted it to partner with Applied Nanotech to optimize its ultra-small-particle nano-inks for the M3D, which uses a finer nozzle configuration than ink-jet printers. Optomec also employed an aerodynamic flow guidance deposition head which can be focused to a virtual nozzle size of 10 microns. Since the deposition head is over 5 millimeters away from the substrate, it allows 3-D surfaces to be "painted" with electronic circuitry.
Applied Nanotech said it is also developing other nano-inks based on other nanoparticles formulations, including carbon nanotubes.