{"id":1143,"date":"2013-07-25T18:26:14","date_gmt":"2013-07-25T18:26:14","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/?p=1143"},"modified":"2013-08-14T20:41:49","modified_gmt":"2013-08-14T20:41:49","slug":"high-performance-near-infrared-light-emitting-devices-using-core-shell-pbs-cds-colloidal-quantum-dots","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/high-performance-near-infrared-light-emitting-devices-using-core-shell-pbs-cds-colloidal-quantum-dots\/","title":{"rendered":"High-performance Near-infrared Light-emitting Devices using Core-shell (PbS-CdS) Colloidal Quantum-dots"},"content":{"rendered":"<p>Near-infrared light sources integrated at room temperature with any planar surface could be realized by harnessing the broad spectral tunability, high brightness, and solution-processability of colloidal quantum-dots (QDs)<sup>[<a href=\"#footnote_0_1143\" id=\"identifier_0_1143\" class=\"footnote-link footnote-identifier-link\" title=\"Y. Shirasaki, G. J. Supran, M. G. Bawendi, and V. Bulovic\u0301, &ldquo;Emergence of Colloidal Quantum-Dot Light-Emitting Technologies,&rdquo; Nature Photonics, vol. 7, pp. 13-23, Jan. 2013.\">1<\/a>]<\/sup>. Yet the performance of near-infrared quantum-dot light-emitting devices (NIR QD-LEDs) has remained relatively low until now<sup>[<a href=\"#footnote_0_1143\" id=\"identifier_1_1143\" class=\"footnote-link footnote-identifier-link\" title=\"Y. Shirasaki, G. J. Supran, M. G. Bawendi, and V. Bulovic\u0301, &ldquo;Emergence of Colloidal Quantum-Dot Light-Emitting Technologies,&rdquo; Nature Photonics, vol. 7, pp. 13-23, Jan. 2013.\">1<\/a>]<\/sup>. Here we show that PbS-CdS core-shell QDs, synthesized via a Pb-to-Cd cation-exchange reaction<sup>[<a href=\"#footnote_1_1143\" id=\"identifier_2_1143\" class=\"footnote-link footnote-identifier-link\" title=\"J. M. Pietryga et al., &ldquo;Utilizing the lability of lead selenide to produce heterostructured nanocrystals with bright, stable infrared emission,&rdquo; J. Am. Chem. Soc., vol. 130, pp. 4879-4885, Mar. 2008.\">2<\/a>]<\/sup> (Figure 1, inset), enhance the peak external quantum efficiency (EQE) of PbS core-only control devices by 50- to 100-fold, up to 4.3 \u00b1 0.3% (Figure 2). By incorporating the core-shell QDs into the novel organic-QD-inorganic hybrid NIR QD-LED architecture depicted in Figure 1, \u201cturn-on\u201d voltages are lowered by 0.6 \u00b1 0.2 V, and per-amp radiant intensities are increased by up to 150 times. Peak EQEs and power conversion efficiencies are more than double those of previous QD-LEDs emitting at wavelengths beyond 1 \u03bcm<sup>[<a href=\"#footnote_2_1143\" id=\"identifier_3_1143\" class=\"footnote-link footnote-identifier-link\" title=\"L. Sun et al., &ldquo;Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control,&rdquo; Nature Nanotechnology, vol. 7, pp. 369-373, May 2012.\">3<\/a>]<\/sup> and are comparable with those of commercial NIR LEDs. We demonstrate that the primary origin of the performance enhancement is passivation of PbS cores by CdS shells against <i>in situ<\/i> photoluminescence quenching, suggesting that core-shell QDs may become a mainstay of high-efficiency NIR QD-LEDs.<\/p>\n<p>Electrically-driven and wavelength-selectable NIR light sources that can be deposited on any substrate and at lower cost than existing (usually epitaxially grown) NIR-emitters have the potential to enhance existing technologies and to trigger the development of new ones<sup>[<a href=\"#footnote_0_1143\" id=\"identifier_4_1143\" class=\"footnote-link footnote-identifier-link\" title=\"Y. Shirasaki, G. J. Supran, M. G. Bawendi, and V. Bulovic\u0301, &ldquo;Emergence of Colloidal Quantum-Dot Light-Emitting Technologies,&rdquo; Nature Photonics, vol. 7, pp. 13-23, Jan. 2013.\">1<\/a>]<\/sup>. Beneficiaries could include optical telecommunications and computing, bio-medical imaging, on-chip bio(sensing) and spectroscopy, night-time surveillance, and other security applications.<\/p>\n\n\t\t<style type=\"text\/css\">\n\t\t\t#gallery-1 {\n\t\t\t\tmargin: auto;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-item {\n\t\t\t\tfloat: left;\n\t\t\t\tmargin-top: 10px;\n\t\t\t\ttext-align: center;\n\t\t\t\twidth: 50%;\n\t\t\t}\n\t\t\t#gallery-1 img {\n\t\t\t\tborder: 2px solid #cfcfcf;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-caption {\n\t\t\t\tmargin-left: 0;\n\t\t\t}\n\t\t\t\/* see gallery_shortcode() in wp-includes\/media.php *\/\n\t\t<\/style>\n\t\t<div id='gallery-1' class='gallery galleryid-1143 gallery-columns-2 gallery-size-medium'><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/high-performance-near-infrared-light-emitting-devices-using-core-shell-pbs-cds-colloidal-quantum-dots\/supran_irqdled_01-2\/'><img width=\"300\" height=\"191\" src=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_01-300x191.jpg\" class=\"attachment-medium size-medium\" alt=\"\" loading=\"lazy\" aria-describedby=\"gallery-1-1144\" srcset=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_01-300x191.jpg 300w, https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_01-1024x653.jpg 1024w, https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_01-220x140.jpg 220w, https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_01.jpg 1500w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1144'>\n\t\t\t\tFigure 1: The novel organic-QD-inorganic hybrid NIR QD-LED architecture, fabricated at room temperature, employed in this work. The inset is a schematic illustration of the Pb-to-Cd cation-exchange reaction used to convert core-only PbS QDs into core-shell PbS-CdS QDs.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/high-performance-near-infrared-light-emitting-devices-using-core-shell-pbs-cds-colloidal-quantum-dots\/supran_irqdled_02-2\/'><img width=\"300\" height=\"250\" src=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_02-300x250.jpg\" class=\"attachment-medium size-medium\" alt=\"\" loading=\"lazy\" aria-describedby=\"gallery-1-1145\" srcset=\"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_02-300x250.jpg 300w, https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_02-1024x855.jpg 1024w, https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_02-220x183.jpg 220w, https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-content\/blogs.dir\/22\/files\/2013\/06\/supran_irqdled_02.jpg 1500w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1145'>\n\t\t\t\tFigure 2: A plot of external quantum efficiency versus current density, demonstrating the ~50- to 100-fold enhancement in QD-LED performance achieved by replacing core-only PbS QDs (black) with core-shell PbS-CdS QDs (green). The inset is a photograph of an array of five QD-LEDs taken with an infrared camera, with the middle device turned on and emitting at a center wavelength of \u03bb=1242 nm . \n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/>\n\t\t<\/div>\n\n<ol class=\"footnotes\"><li id=\"footnote_0_1143\" class=\"footnote\">Y. Shirasaki, G. J. Supran, M. G. Bawendi, and V. Bulovic\u0301, \u201cEmergence of Colloidal Quantum-Dot Light-Emitting Technologies,\u201d <i>Nature Photonics<\/i>, vol. 7, pp. 13-23, Jan. 2013. [<a href=\"#identifier_0_1143\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>] [<a href=\"#identifier_1_1143\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>] [<a href=\"#identifier_4_1143\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><li id=\"footnote_1_1143\" class=\"footnote\">J. M. Pietryga <i>et al.<\/i>, \u201cUtilizing the lability of lead selenide to produce heterostructured nanocrystals with bright, stable infrared emission,\u201d <i>J. Am. Chem. Soc.<\/i>, vol. 130, pp. 4879-4885, Mar. 2008. [<a href=\"#identifier_2_1143\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><li id=\"footnote_2_1143\" class=\"footnote\">L. Sun <i>et al.<\/i>, \u201cBright infrared quantum-dot light-emitting diodes through inter-dot spacing control,\u201d <i>Nature Nanotechnology<\/i>, vol. 7, pp. 369-373, May 2012. [<a href=\"#identifier_3_1143\" class=\"footnote-link footnote-back-link\">&#8617;<\/a>]<\/li><\/ol>","protected":false},"excerpt":{"rendered":"<p>Near-infrared light sources integrated at room temperature with any planar surface could be realized by harnessing the broad spectral tunability,&#8230;<\/p>\n","protected":false},"author":370,"featured_media":1145,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[28,8,6083],"tags":[4232,6131],"_links":{"self":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts\/1143"}],"collection":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/users\/370"}],"replies":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/comments?post=1143"}],"version-history":[{"count":11,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts\/1143\/revisions"}],"predecessor-version":[{"id":2504,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/posts\/1143\/revisions\/2504"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/media\/1145"}],"wp:attachment":[{"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/media?parent=1143"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/categories?post=1143"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mtlsites.mit.edu\/annual_reports\/2013\/wp-json\/wp\/v2\/tags?post=1143"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}