وأيد هذا العمل من قبل R تكنولوجيا المعلومات والاتصالات وبرنامج D من MSIP / IITP (R0190-15-2040، تطوير نظام إدارة التكوين محتويات وجهاز محاكاة للطباعة 3D باستخدام المواد الذكية).

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الكتاب ليس لديهم ما يكشف.

تم إدراج كابل SMF في حفرة كابل SMF على رقاقة، كما هو مبين في نقطة مستطيلة الشكل 6A. لأن الكابل حفرة SMF أكبر من قطر الكابل، تم استخدام الايبوكسي الغراء لاغلاق الفجوة لمنع تسرب من الحل الجسيمات المتدفقة. قبل تطبيق الغراء الايبوكسي، كتلة الذهب وحافة كابل يجب أن تكون محاذاة محوري باليد باستخدام المجهر. على الرغم من أنها مثالية للحافة كابل إدراج وnanohole إلى الانحياز محوري، وهو اختلال طفيف يمكن السكوت لأن شعاع الليزر يتباعد بمجرد خروجه من نهاية كابل NA SMF حافة 0.14، وشعاع يؤثر على أكبر من ذلك بكثير منطقة. لأنه تم تكوين رقاقة أن يكون عمودي على المحور البصري للالمجهر، ونحن لا يمكن أن نلاحظ مباشرة موقع nanohole. موقع nanohole لا يمكن تحديدها بشكل غير مباشر من خلال مراقبة الموقع من الجسيمات المحاصرين plasmonically في nanohole. ايمكن توفير حل عن طريق تثبيت الكاميرا على كابل الألياف واستخدامه لمراقبة كتلة الذهب. والسمة المميزة للرقاقة هو قدرته على رصد حركة الجسيمات بالقرب من nanohole plasmonic في الوقت الحقيقي. حركة الجسيمات تتبع السيناريو هو موضح أدناه. عندما تيارات السائل الجسيمات إلى الأمام، بعض الجسيمات تتحرك نحو كتلة الذهب. في بعض الحالات، الجسيمات يحصل خصوصا على مقربة من حافة nanohole بسبب جاذبية للnanohole وفي النهاية يصبح يجمد. في هذه اللحظة، مارست القوة الضوئية على تجاوز جسيم القوة السوائل. وفي وقت لاحق، والجسيمات يجمد يهرب من حافة nanohole عندما يزيد سرعة السائل. وبالتالي، فإن قوة السوائل تصبح أقوى من القوة البصرية. ويمكن قياس قوة محاصرة القصوى من هذه سرعة السائل الطرفية. ومع ذلك، فإن معادلة قوة السحب التقليدية لا يمكن استخدامها لأن الجسيمات في اتصال جسدي مع زالجدار القديم في nanohole. للنظر في تأثير سطح الجدار الذهب، استخدمنا طريقة محدود، عنصر، والتي تعتبر حركة السوائل بالقرب من السطح، وحصل على قوة السوائل. وأدخلنا الإعداد منتاش plasmonic الجديد الذي تمكن من رصد ديناميات الجسيمات على طول محور شعاع الليزر. في المقابل، الدراسات السابقة قدم فقط حركة الجسيمات في الطائرة عمودي على محور شعاع الليزر، مثل مع nanoblock 12، nanodisk 13 و 14 و 19 و 21 و 20 nanostick، وnanopyramid 18. وعلاوة على ذلك، في حالة أنواع nanohole، لا يمكن إلا أن يشهد محاصرة من خلال رصد إشارة تشتت، وليس عن طريق رصد بصرية 10 و 11 و 23. ومع ذلك،لم نتمكن من قياس بدقة موقف جسيم بسبب القدرات المحدودة لتقنيات التصوير الحالية. ينبغي تحسين جودة التصوير أيضا على تأكيد القياسات خلع بالضبط. هذه التقنية يمكن تطبيقها في توصيف وbiosensing من جزيء واحد.

القدرة على التعامل مع الأشياء الميكروسكيل هي ميزة لا غنى عنها للعديد من التجارب الصغيرة / نانو. يمكن التلاعب الاتصال مباشرة يضر الكائنات التلاعب بها. الافراج عن الكائنات التي عقدت سابقا هو أيضا تحديا بسبب مشاكل stiction. للتغلب على هذه القضايا، العديد من الطرق غير المباشرة باستخدام فلويديك 1، 2 الكهربائية، والمغناطيسية 3، أو قوات الضوئية 4، 5، 6، 7، 8 تم اقتراحها. تستند ملاقط Plasmonic التي تستخدم قوات الضوئية على فيزياء استثنائية تعزيز المجال عدة أوامر أكبر من شدة الحادث 9. هذا التعزيز ميداني قوي للغاية تمكن محاصرة من جزيئات صغيرة جدا. على سبيل المثال، فقد تبين لشل والتلاعب النانوالأشياء، مثل جزيئات البوليستيرين 7 و 10 و 11 و 12 و 13 و 14 و 15 سلاسل البوليمر والبروتينات 16، النقاط الكمومية 17، وجزيئات DNA 8، 18. دون ملاقط plasmonic، فمن الصعب أن الجسيمات النانوية فخ لأنها تختفي بسرعة قبل أن يتم فحصها بشكل فعال أو لكانت معطوبة بسبب كثافة عالية من الليزر. وقد استخدمت العديد من الدراسات plasmonic مختلف الهياكل الذهب النانوية. يمكننا تصنيف الهياكل الذهب وجاحظ أنواع nanodisk 12، 13، 14، 15، 19 <sتصل&gt;، 20، 21 أو قمعها أنواع nanohole 7، 8، 10، 11، 22، 23. من حيث الراحة والتصوير، وأنواع nanodisk هي أكثر ملاءمة من أنواع nanohole لأن لهذا الأخير، يمكن للركائز الذهب عرقلة عرض الملاحظة. وعلاوة على ذلك، يحدث محاصرة plasmonic بالقرب من هيكل plasmonic ويجعل المراقبة أكثر تحديا. إلى حد علمنا، محاصرة plasmonic على أنواع nanohole تم التحقق فقط باستخدام إشارات نثر غير المباشرة. ومع ذلك، لا الملاحظات المباشرة الناجحة، مثل الصور المجهرية، فقد تم الإبلاغ عنها. ووصف عدد قليل من الدراسات الموقف من الجسيمات المحاصرين. وقدم واحدة من هذه النتيجة وانغ وآخرون. وأنشأوا عمود الذهب على ركيزة الذهب، ولاحظ عالمادة الحركة باستخدام المجهر الفلورسنت 24. ومع ذلك، هذا هو فعالة فقط لرصد الحركات الجانبية وليس في اتجاه مواز لمحور الحزمة. في هذه الورقة، ونحن نقدم تصميم رقاقة وتلفيق إجراءات الموائعية جديدة. باستخدام هذه الشريحة، علينا أن نظهر رصد الجسيمات المحاصرين plasmonically، سواء في اتجاهات متوازية ومتعامدة مع البنية النانوية plasmonic. وعلاوة على ذلك، فإننا قياس القوة القصوى للجسيمات يجمد عن طريق زيادة سرعة السائل للعثور على سرعة تحول في رقاقة. هذه الدراسة هي فريدة من نوعها لأن معظم الدراسات على ملاقط plasmonic لا يمكن أن تظهر من الناحية الكمية قوات محاصرة القصوى المستخدمة في الاجهزة الخاصة بهم التجريبية.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Negative photoresist&#160;</td>
			<td>MicroChem</td>
			<td>SU-8 2075</td>
		</tr>
		<tr>
			<td>Developer</td>
			<td>MicroChem</td>
			<td>SU-8 Developer</td>
		</tr>
		<tr>
			<td>Positive photoresist&#160;</td>
			<td>Merck Ltd.</td>
			<td>AZ GXR-601</td>
		</tr>
		<tr>
			<td>AZ Photoresist Developers</td>
			<td>Merck Ltd.</td>
			<td>AZ 300 MIF</td>
		</tr>
		<tr>
			<td>HMDS</td>
			<td>Merck Ltd.</td>
			<td>AZ Adhesion Promoter</td>
		</tr>
		<tr>
			<td>Aligner</td>
			<td>Midas System</td>
			<td>MDA 400M</td>
		</tr>
		<tr>
			<td>Atmospheric plasma machine&#160;</td>
			<td>Atmospheric Process 
			Plasma Co.</td>
			<td>IDP-1000</td>
		</tr>
		<tr>
			<td>Polydimethylsiloxane (PDMS)</td>
			<td>Dow Corning</td>
			<td>Sylgard 184 A/B</td>
		</tr>
		<tr>
			<td>Gold coated test slides</td>
			<td>EMF Co.</td>
			<td>TA124(Ti/Au)</td>
		</tr>
		<tr>
			<td>Au etchant&#160;</td>
			<td>Transene Inc.</td>
			<td>TFA</td>
		</tr>
		<tr>
			<td>Ti etchant&#160;</td>
			<td>Transene Inc.</td>
			<td>TFT</td>
		</tr>
		<tr>
			<td>40X objective lens&#160;</td>
			<td>Edmund Optics</td>
			<td>40X DIN</td>
		</tr>
		<tr>
			<td>60X water immersion 
			objective lens&#160;</td>
			<td>Olympus</td>
			<td>LUMPLFLN 60XW</td>
		</tr>
		<tr>
			<td>Optical fiber incident laser&#160;</td>
			<td>IPG Photonic</td>
			<td>YLR 10</td>
		</tr>
		<tr>
			<td>SMF coupler</td>
			<td>Thorlabs</td>
			<td>MBT612D/M</td>
		</tr>
		<tr>
			<td>Syringe micropump</td>
			<td>Harvard</td>
			<td>PC2 70-4501</td>
		</tr>
		<tr>
			<td>Fluorescent microscope&#160;</td>
			<td>Olympus</td>
			<td>IX-51</td>
		</tr>
		<tr>
			<td>Plasma system</td>
			<td>Femto Science Inc</td>
			<td>CUTE-MPR</td>
		</tr>
	</tbody>
</table>

plasmonic trapping and release of nanoparticles in a monitoring environment

ملاقط Plasmonic استخدام بولاريتون مأكل سطح لحصر الأجسام النانوية قطوب. بين تصاميم مختلفة من ملاقط plasmonic، سوى عدد قليل يمكن أن نلاحظ جزيئات يجمد. وعلاوة على ذلك، فإن عددا محدودا من الدراسات قياسها تجريبيا قوات exertable على الجسيمات. يمكن تصنيف التصاميم وجاحظ نوع nanodisk أو قمعها نوع nanohole. لهذا الأخير، والمراقبة المجهرية هي صعبة للغاية. في هذه الورقة، وإدخال نظام منتاش plasmonic جديد لرصد الجسيمات، سواء في اتجاهات متوازية ومتعامدة مع محور متماثل هيكل nanohole plasmonic. هذه الميزة تتيح لنا مراقبة حركة كل جسيم بالقرب من حافة nanohole. وعلاوة على ذلك، يمكننا تقدير كمي لقوات محاصرة القصوى باستخدام قناة الموائعية جديدة.

يظهر عملية تصنيع متناهية والذهب nanohole لوحة PDMS في أرقام 1 و 2. طريقة الجمع بين البابين الثاني ويظهر رقاقة الفعلية في الشكل (3). تم قطع PDMS للكشف داخل القناة من جانب رقاقة. ومع ذلك، فإنه من الصعب مراقبة الجزيئات المتدفقة في القناة بسبب خشونة سطح الطائرة القطع. ولذلك، قدمنا طريقة PDMS طلاء لحل هذه المشكلة، كما هو مبين في الشكل (4). لاحظنا 5 ميكرون، وتتدفق جزيئات البوليستيرين في رقاقة لتأكيد تأثير طلاء PDMS. ويبين الشكل 5 رقاقة ملفقة الفعلية والجزيئات التي لوحظت في رقاقة باستخدام المجهر. الشكل 5A وج هي قبل وبعد appearaالامتحانات التنافسية الوطنية من رقاقة. الشكل 5B و د هي الأسطح تضخيم كل منها. ويبين الشكل 5E الجزيئات المتدفقة واضحة، في حين يبين الشكل 5F أن حواف الجزيئات لا سيما واضحة، وأنه يمكن رصد الحركات. على النحو الوارد أعلاه، وطلاء PDMS من سطح رقاقة ضروري لرصد الجسيمات المحاصرين. ويبين الشكل 6 100 نانومتر البوليسترين الجسيمات تمر محاصرة البصرية plasmonic من قبل النظام منتاش plasmonic. تم استخدام كابل SMF مع 0.14 الفتحة العددية (NA). تم إدراج أنبوب في الثقوب مدخل / مخرج للقناة رقاقة. تم استخدام MICROPUMP لادخال وجمع 100 نانومتر البوليسترين الفلورسنت حل الجسيمات. التأكيد على ظهور الداخلية للجسيمات المحاصرين من قبل ظاهرة plasmonic، تم توسيع الأجزاء المتقطعة في الشكل 6A كما أقحم، <stroنانوغرام&gt; الشكل 6B. وقد تنبعث الليزر تسليمها بواسطة كابل SMF إدراجها في رقاقة إلى nanohole من كتلة الذهب، والجسيمات تدفقت من اليسار إلى اليمين. تم الكشف عن الحركة على حافة nanohole، حيث كان تعزيز مجال الأقوى. ويبين الشكل 7 صور متتالية حيث كان محاصرا 100 نانومتر الفلورسنت الجسيمات البوليسترين التي تدفقت في متناهية وأفرج عنه في nanohole في شدة 0.42 ميغاواط / ميكرون 2. تدفقت الجسيمات بسرعة ثابتة من 3.4 ميكرون / ثانية في اتجاه السائل، كما هو مبين في الشكل 7A. بعد أن تحولت الليزر على، واحدة من الجزيئات كان محاصرا في nanohole، كما هو مبين في الشكل 7B. على العكس من ذلك، تدفقت جسيم آخر في مجرى، كما هو مبين في الشكل 7C. ثم، تم زيادة سرعة تدفق حتى نجا من الجسيمات المحاصرين. ويبين الشكل 7D المنتمادة الهروب من الفخ. في هذه اللحظة، يمكننا تقدير قوة محاصرة مع الملاحظة المباشرة عن طريق قياس سرعة السائل عندما هرب الجسيمات. كما عملنا في الاتجاه المعاكس. بدلا من زيادة سرعة السائل، ونحن انخفضت تدريجيا قوة الليزر في التناقصات من 1 ميغاواط وسجلت كثافة عندما هرب الجسيمات. ويعرف هذا كثافة الليزر كحد ادنى كثافة محاصرة الليزر وقياس ليبلغ 0.24 ميغاواط / ميكرون 2. <img alt="شكل 1" src="/files/ftp_upload/55258/55258fig1.jpg" /> الشكل 1. تصنيع متناهية PDMS. (أ) إعداد سي الرقاقة. (ب) الطلاء الواقي الضوئي دوران الرقاقة. (ج) المصنعة العفن متناهية من قبل عملية ضوئيه. (د) PDMS التصلب باستخدام الفرن بعد صب حل PDMS على رقاقة. (ه) PDMS قطع متناهية. (و) PDMS متناهية مفرزة من الرقاقة. (ز) مدخل / مخرج والثقوب كابل SMF ثقب في متناهية PDMS. (ح) الفعلية عزز PDMS على رقاقة. (ط) الفعلية PDMS فصل متناهية. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55258/55258fig1large.jpg" target="_blank">الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم.</a> <img alt="الشكل 2" src="/files/ftp_upload/55258/55258fig2.jpg" /> الشكل 2. التصنيع من nanohole على طبق من ذهب بعد عملية الحفر. (أ) ترسب الاتحاد الافريقي ومنظمة الشفافية الدولية على الزجاج. طلاء تدور (ب) الواقي من لوحة من الذهب. (ج) إزالة مقاومة للضوء الذائب بعد التعرض للأشعة فوق البنفسجية ضوء. (د) الاتحاد الافريقي الحفر. (ه) تي الحفر. (و) المتبقية مقاومة للضوء إعادة<html> moval. (ز) Nanohole الطحن بواسطة شعاع أيون تركيزا على كتلة الذهب. (ح) الفعلي كتلة الذهب ملفقة. (ط) nanohole المضروب الفعلي على كتلة الذهب. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55258/55258fig2large.jpg" target="_blank">الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم.</a> <img alt="الشكل (3)" src="/files/ftp_upload/55258/55258fig3.jpg" /> الشكل 3. عملية جمعية رقاقة. (أ) إصلاح متناهية PDMS ولوحة من الذهب على حامل القناع ومرحلة الركيزة، على التوالي، ومجهزة على اليجنر. (ب) الجمع بين متناهية جزء PDMS وطبق من ذهب بعد المعالجة السطحية مع O 2 البلازما. (ج، د) تجميعها رقاقة بعد الجمع. (ه) إزالة كميات زائدة من متناهية PDMS.<html> ce.jove.com/files/ftp_upload/55258/55258fig3large.jpg &quot;الهدف =&quot; _ فارغة &quot;&gt; الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم. <img alt="الشكل (4)" src="/files/ftp_upload/55258/55258fig4.jpg" /> الرقم 4. عملية السطح تحسين خشونة من قبل PDMS الطلاء. (أ) إزالة كميات زائدة باستخدام شفرة حلاقة بعد الجمع بين شطري. (ب) خشونة عالية سطح رقاقة بعد القطع. (ج) PDMS حل طلاء تدور في طبق بتري. (د) غمس سطح نافذة رقاقة في حل PDMS المغلفة زيادة ونقصان. (ه) المغلفة PDMS رقاقة مفرزة من طبق بيتري. (و) تحسين خشونة السطح PDMS الطلاء. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55258/55258fig4large.jpg" target="_blank">الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم.</a> SS = &quot;jove_content&quot; FO: المحافظة على together.within الصفحات = &quot;1&quot;&gt; <img alt="الرقم 5" src="/files/ftp_upload/55258/55258fig5.jpg" /> الشكل 5. تجميعها رقاقة والمراقبة من جزيئات البوليستيرين 5 ميكرون في متناهية قبل وبعد PDMS الطلاء. (أ، ب) رقاقة قبل PDMS الطلاء وعرض المكبرة. (ج، د) رقاقة بعد PDMS الطلاء وعرض المكبرة. (ه، و) مراقبة الجزيئات في متناهية قبل وبعد طلاء PDMS. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55258/55258fig5large.jpg" target="_blank">الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم.</a> <img alt="الشكل (6)" src="/files/ftp_upload/55258/55258fig6.jpg" /> الرقم 6. تصميم نظام منتاش plasmonic. (أ) تخطيطي لنظام منتاش plasmonic. (ب </sترونج&gt;) محاصرة من 100 نانومتر الجسيمات البوليسترين الفلورسنت على حافة nanohole في رقاقة. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55258/55258fig6large.jpg" target="_blank">الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم.</a> <img alt="الرقم 7" src="/files/ftp_upload/55258/55258fig7.jpg" /> الرقم 7. محاصرة وإطلاق سراح من 100 نانومتر الجسيمات البوليسترين الفلورسنت في متناهية. (أ) متناهية مع الجسيمات التي تصب في تيار. (ب، ج) الجسيمات المحاصرين في nanohole بالمقارنة مع جزيء آخر. (د) الجسيمات التي هربت من فخ نظرا لقوة السوائل زيادة. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55258/55258fig7large.jpg" target="_blank">الرجاء انقر هنا لمشاهدة نسخة أكبر من هذا الرقم.</a>

Watch this Scientific Journal Video about Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment at JoVE.com

Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

ويرد عملية تصنيع الرقائق الدقيقة التي تتضمن ملاقط plasmonic هنا. رقاقة تمكن التصوير من الجسيمات المحاصرين لقياس قوات محاصرة القصوى.

Plasmonic اصطياد والإفراج عن النانوية في بيئة المراقبة

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few ...

plasmonic-trapping-release-nanoparticles-monitoring

Nanyang Technological University

Research

JoVE Journal

Engineering

7.5K Views.  Korea Basic Science Institute (KBSI).  ويرد عملية تصنيع الرقائق الدقيقة التي تتضمن ملاقط plasmonic هنا. رقاقة تمكن التصوير من الجسيمات المحاصرين لقياس قوات محاصرة القصوى. 

Video: Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

الكريستالات السليكون الخلايا الشمسية الأغشية الرقيقة مع Plasmonic معززة للضوء للاحتباس

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

Optical Trapping of Nanoparticles

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3.
A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure.
The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres.

The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.

البصرية محاصرة من الجسيمات النانوية

Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping ...

Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular organelles 2,3, as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope 4,5 at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale.

The system described herein employs a traditional optical trap as well as an independent holographic optical trapping line, capable of creating and manipulating multiple traps. This allows for the creation of complex geometric arrangements of refractive particles while also permitting simultaneous high-speed, high-resolution measurements of the activity of biological enzymes.

بناء مجهر عالي الدقة مع التقليدية والتصوير المجسم قدرات ملائمة بصري

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular ...

Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters

In this video article we present a detailed demonstration of a highly efficient method for generating terahertz waves. Our technique is based on photoconduction, which has been one of the most commonly used techniques for terahertz generation 1-8. Terahertz generation in a photoconductive emitter is achieved by pumping an ultrafast photoconductor with a pulsed or heterodyned laser illumination. The induced photocurrent, which follows the envelope of the pump laser, is routed to a terahertz radiating antenna connected to the photoconductor contact electrodes to generate terahertz radiation. Although the quantum efficiency of a photoconductive emitter can theoretically reach 100%, the relatively long transport path lengths of photo-generated carriers to the contact electrodes of conventional photoconductors have severely limited their quantum efficiency. Additionally, the carrier screening effect and thermal breakdown strictly limit the maximum output power of conventional photoconductive terahertz sources. To address the quantum efficiency limitations of conventional photoconductive terahertz emitters, we have developed a new photoconductive emitter concept which incorporates a plasmonic contact electrode configuration to offer high quantum-efficiency and ultrafast operation simultaneously. By using nano-scale plasmonic contact electrodes, we significantly reduce the average photo-generated carrier transport path to photoconductor contact electrodes compared to conventional photoconductors 9. Our method also allows increasing photoconductor active area without a considerable increase in the capacitive loading to the antenna, boosting the maximum terahertz radiation power by preventing the carrier screening effect and thermal breakdown at high optical pump powers. By incorporating plasmonic contact electrodes, we demonstrate enhancing the optical-to-terahertz power conversion efficiency of a conventional photoconductive terahertz emitter by a factor of 50 10.

We describe methods for the design, fabrication, and experimental characterization of plasmonic photoconductive emitters, which offer two orders of magnitude higher terahertz power levels compared to conventional photoconductive emitters.

تصميم وتصنيع، والتجريبية توصيف Plasmonic بواعث تيراهيرتز موصل كهربائي بفعل الضوء

In this video article we present a detailed demonstration of a highly efficient method for generating terahertz waves. Our technique is based on ...

Evaluating Plasmonic Transport in Current-carrying Silver Nanowires

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information support1,2,3. In this context, metal nanowires are especially desirable for realizing dense routing networks4. A prerequisite to operate such shared nanowire-based platform relies on our ability to electrically contact individual metal nanowires and efficiently excite surface plasmon polaritons5 in this information support. In this article, we describe a protocol to bring electrical terminals to chemically-synthesized silver nanowires6 randomly distributed on a glass substrate7. The positions of the nanowire ends with respect to predefined landmarks are precisely located using standard optical transmission microscopy before encapsulation in an electron-sensitive resist. Trenches representing the electrode layout are subsequently designed by electron-beam lithography. Metal electrodes are then fabricated by thermally evaporating a Cr/Au layer followed by a chemical lift-off. The contacted silver nanowires are finally transferred to a leakage radiation microscope for surface plasmon excitation and characterization8,9. Surface plasmons are launched in the nanowires by focusing a near infrared laser beam on a diffraction-limited spot overlapping one nanowire extremity5,9. For sufficiently large nanowires, the surface plasmon mode leaks into the glass substrate9,10. This leakage radiation is readily detected, imaged, and analyzed in the different conjugate planes in leakage radiation microscopy9,11. The electrical terminals do not affect the plasmon propagation. However, a current-induced morphological deterioration of the nanowire drastically degrades the flow of surface plasmons. The combination of surface plasmon leakage radiation microscopy with a simultaneous analysis of the nanowire electrical transport characteristics reveals the intrinsic limitations of such plasmonic circuitry.

Silver nanowires can simultaneously transport electrons and optical information in the form of surface plasmons. A procedure is described here to realize such a shared circuitry and the limitations at propagating both information carriers are evaluated.

تقييم النقل Plasmonic في سيلفر الحالية الحاملة الأسلاك المتناهية الصغر

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information ...

Analyzing the Movement of the Nauplius 'Artemia salina' by Optical Tracking of Plasmonic Nanoparticles

We demonstrate how optical tweezers may provide a sensitive tool to analyze the fluidic vibrations generated by the movement of small aquatic organisms. A single gold nanoparticle held by an optical tweezer is used as a sensor to quantify the rhythmic motion of a Nauplius larva (Artemia salina) in a water sample. This is achieved by monitoring the time dependent displacement of the trapped nanoparticle as a consequence of the Nauplius activity. A Fourier analysis of the nanoparticle&#39;s position then yields a frequency spectrum that is characteristic to the motion of the observed species. This experiment demonstrates the capability of this method to measure and characterize the activity of small aquatic larvae without the requirement to observe them directly and to gain information about the position of the larvae with respect to the trapped particle. Overall, this approach could give an insight on the vitality of certain species found in an aquatic ecosystem and could expand the range of conventional methods for analyzing water samples.

Analyzing the Movement of the Nauplius 'Artemia salina' by Optical Tracking of Plasmonic Nanoparticles

We use optical tracking of plasmonic nanoparticles to probe and characterize the frequency movements of aquatic organisms.

تحليل حركة اليرقات &#39;<em&gt; الأرتيميا سالينا</em&gt; من خلال تتبع بصري من Plasmonic النانوية

We demonstrate how optical tweezers may provide a sensitive tool to analyze the fluidic vibrations generated by the movement of small aquatic organisms. A ...

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial resolution, and is even capable of providing atomically resolved elemental maps. In this technique, a highly focused electron beam is incident upon a thin sample and the energy of emitted X-rays is measured in order to determine the atomic species of material within the beam path. This elementally sensitive spectroscopy technique can be extended to three dimensional tomographic imaging by acquiring multiple spectrum images with the sample tilted along an axis perpendicular to the electron beam direction.
Elemental distributions within single nanoparticles are often important for determining their optical, catalytic and magnetic properties. Techniques such as X-ray tomography and slice and view energy dispersive X-ray mapping in the scanning electron microscope provide elementally sensitive three dimensional imaging but are typically limited to spatial resolutions of &gt; 20 nm. Atom probe tomography provides near atomic resolution but preparing nanoparticle samples for atom probe analysis is often challenging. Thus, elementally sensitive techniques applied within the scanning transmission electron microscope are uniquely placed to study elemental distributions within nanoparticles of dimensions 10-100 nm.
Here, energy dispersive X-ray (EDX) spectroscopy within the STEM is applied to investigate the distribution of elements in single AgAu nanoparticles. The surface segregation of both Ag and Au, at different nanoparticle compositions, has been observed.

The use of energy dispersive X-ray tomography in the scanning transmission electron microscope to characterize elemental distributions within single nanoparticles in three dimensions is described.

التصوير المقطعي الطاقة المتشتتة الأشعة السينية ل3D عنصري رسم الخرائط من الجسيمات النانوية الفردية

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial ...

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently. 
Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches. 
In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies.

Saturable and reverse saturable scattering were discovered in isolated plasmonic particles and adopted as a novel non-bleaching contrast method in super-resolution microscopy. Here the experimental procedures of detecting and extracting nonlinear scattering are explained in detail, as well as how to enhance resolution with the aid of saturated excitation microscopy.

قياس التشتت الغير خطية من الجسيمات النانوية Plasmonic واحدة

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus ...

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl4) to neutral gold Au(0) by reducing agents, such as sodium citrate or sodium borohydride. The extension of this method to decorate iron oxide or similar nanoparticles with gold nanoparticles to create multifunctional hybrid Fe2O3-Au nanoparticles is straightforward. This approach yields fairly good control over Au nanoparticle dimensions and loading onto Fe2O3. Additionally, the Au metal size, shape, and loading can easily be tuned by changing experimental parameters (e.g., reactant concentrations, reducing agents, surfactants, etc.). An advantage of this procedure is that the reaction can be done in air or water, and, in principle, is amenable to scaling up. The use of such optically tunable Fe2O3-Au nanoparticles for hyperthermia studies is an attractive option as it capitalizes on plasmonic heating of gold nanoparticles tuned to absorb light strongly in the VIS-NIR region. In addition to its plasmonic effects, nanoscale Au provides a unique surface for interesting chemistries and catalysis. The Fe2O3 material provides additional functionality due to its magnetic property. For example, an external magnetic field could be used to collect and recycle the hybrid Fe2O3-Au nanoparticles after a catalytic experiment, or alternatively, the magnetic Fe2O3 can be used for hyperthermia studies through magnetic heat induction. The photothermal experiment described in this report measures bulk temperature change and nanoparticle solution mass loss as functions of time using infrared thermocouples and a balance, respectively. The ease of sample preparation and the use of readily available equipment are distinct advantages of this technique. A caveat is that these photothermal measurements assess the bulk solution temperature and not the surface of the nanoparticle where the heat is transduced and the temperature is likely to be higher.

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

We describe the synthesis and properties of multifunctional Fe2O3-Au nanoparticles produced by a wet chemical approach and investigate their photothermal properties using laser irradiation. The composite Fe2O3-Au nanoparticles retain the properties of both materials, creating a multifunctional structure with excellent magnetic and plasmonic properties.

هجين متعدد الوظائف الحديد<sub&gt; 2</sub&gt; O<sub&gt; 3</sub&gt; -Au النانوية لالتدفئة Plasmonic كفاءة

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl4) to ...

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m2&#183;g-1. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

A protocol for fabricating porous, nanostructured yttria-stabilized-zirconia (YSZ) scaffolds at temperatures between 1,000 &#176;C and 1,400 &#176;C is presented.

تصنيع درجة الحرارة عالية من ذات البنية النانومترية اليتريا-استقرت-زركونيا (YSZ) السقالات من قبل<em&gt; في الموقع</em&gt; الكربون النموذجيه Xerogels

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...