We introduce NanoPen, a novel technique for low optical power intensity, flexible, real-time reconfigurable, and large-scale light-actuated patterning of single or multiple nanoparticles, such as metallic spherical nanocrystals, and one-dimensional nanostructures, such as carbon nanotubes. NanoPen is capable of dynamically patterning nanoparticles over an area of thousands of square micrometers with light intensities <10 W/cm2 (using a commercial projector) within seconds. Various arbitrary nanoparticle patterns and arrays (including a 10 × 10 array covering a 0.025 mm2 area) are demonstrated using this capability. One application of NanoPen is presented through the creation of surface-enhanced Raman spectroscopy hot-spots by patterning gold nanoparticles of 90 nm diameter with enhancement factors exceeding 107 and picomolar concentration sensitivities.
“奈米鋼筆”破解粒子快速鋪置難題
改寫自科學網
物理學家組織網9月2日報導稱，美國加州的研究人員開發出一種稱為“奈米鋼筆 ”（NanoPen）的新技術，可將奈米粒子快速鋪置成奈米線或是奈米電路，從而解決了一個長期困擾科學家的難題，為製造下一代電子設備、進行醫療診斷測試以及其他備受期待的奈米科技應用帶來了希望。
奈米粒子極其微小，其直徑還不足人發直徑的五萬分之一。如何快速有效地將這些微小的粒子鋪置成人們想要的形狀，一直是長期困擾科學家的難題。該項技術的研發人員之一、加州大學柏克萊分校(University of California, Berkeley)電子工程與電腦科學系(Department of Electrical Engineering and Computer Sciences)的吳明（Ming C. Wu）指出，雖然目前科研人員已經開發出幾種鋪設奈米粒子的方法，但這些技術往往過於複雜，所用儀器龐大，耗時費力，往往需要花費幾分鐘甚至幾小時才能完成。同時這些技術對溫度的要求也極高，需要高溫將奈米結構固附於目標表面。這些弱點都妨礙了它們的廣泛應用。
報導稱，“奈米鋼筆”技術有效地解決了這些問題。研究人員使用這種“鋼筆”，在相對較低的溫度和光照條件下，可迅速地將各種奈米粒子鋪置成特定圖案。這個過程需要使用一種特殊的“光導”表面，僅用幾秒鐘即可完成。而通過調節電壓、光線強度和暴露時間，研究人員可調整奈米粒子鋪設的面積和密度。
參與該項技術研發的還有來自美國勞倫斯利弗莫爾國家實驗室(Lawrence Livermore National Laboratory)和勞倫斯柏克萊國家實驗室(Lawrence Berkeley National Laboratory)的研究人員。而相關研究發表在美國化學學會刊物《奈米快報》（Nano Letters）上。（來源：科技日報 劉海英）
PHYSORG.COM原文報導
'NanoPen' may write new chapter in nanotechnology manufacturing
September 2nd, 2009
Nano Letters原文論文
NanoPen: Dynamic, Low-Power, and Light-Actuated Patterning of Nanoparticles
Arash Jamshidi†, Steven L. Neale†, Kyoungsik Yu†, Peter J. Pauzauskie‡, Peter James Schuck§, Justin K. Valley†, Hsan-Yin Hsu†, Aaron T. Ohta† and Ming C. Wu*†
Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, Chemical Sciences Division, Lawrence Livermore National Laboratory, Berkeley, California 94720, and Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
Ming C. Wu在UC Berkeley的研究實驗室
IPL: Integrated Photonics Laboratory
Device structure used in optoelectronic tweezers (OET). Liquid that contains microscopic particles is
sandwiched between the top ITO glass and the bottom photosensitive surface consisting of ITO-coated glass topped with multiple featureless layers: heavily doped a-Si:H, undoped a-Si:H, and silicon nitride. The top and bottom surfaces are biased with an AC electric signal. The illumination source is an LED operating at a wavelength of 625 nm (Lumileds, Luxeon Star/O). The optical images shown on the digital micromirror display (DMD) are focused onto the photosensitive surface and create the non-uniform electric field for DEP manipulation.
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