{"id":74008,"date":"2025-06-10T14:13:09","date_gmt":"2025-06-10T12:13:09","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=74008"},"modified":"2025-06-25T14:29:46","modified_gmt":"2025-06-25T12:29:46","slug":"when-graphene-starts-to-glow-without-heating-up","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/newsletter\/when-graphene-starts-to-glow-without-heating-up.html","title":{"rendered":"When graphene starts to glow without heating up"},"content":{"rendered":"<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-mbqaem2b-b4a58135bcb3536eda97284645960765\">\n#top .av-special-heading.av-mbqaem2b-b4a58135bcb3536eda97284645960765{\npadding-bottom:10px;\n}\nbody .av-special-heading.av-mbqaem2b-b4a58135bcb3536eda97284645960765 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-mbqaem2b-b4a58135bcb3536eda97284645960765 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-mbqaem2b-b4a58135bcb3536eda97284645960765 av-special-heading-h1  avia-builder-el-0  el_before_av_hr  avia-builder-el-first'><h1 class='av-special-heading-tag'  itemprop=\"headline\"  >When graphene starts to glow without heating up<\/h1><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n<div  class='hr av-2wh9e3l-f6f25effe8c9cdb169898f7a544f1b5b hr-default  avia-builder-el-1  el_after_av_heading  el_before_av_one_third'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-2dfkgox-492b6f658dede1ae8e08e32f7113ad77\">\n@keyframes av_boxShadowEffect_av-2dfkgox-492b6f658dede1ae8e08e32f7113ad77-column {\n0%   { box-shadow:  0 0 0 0 #efefef; opacity: 1; }\n100% { box-shadow:  0 0 7px 0 #efefef; opacity: 1; }\n}\n.flex_column.av-2dfkgox-492b6f658dede1ae8e08e32f7113ad77{\nbox-shadow: 0 0 7px 0 #efefef;\npadding:15px 15px 15px 15px;\nbackground-color:#ffffff;\n}\n<\/style>\n<div  class='flex_column av-2dfkgox-492b6f658dede1ae8e08e32f7113ad77 av_one_third  avia-builder-el-2  el_after_av_hr  el_before_av_one_third  first flex_column_div shadow-not-animated'     ><style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-mbqafqhu-b1e7cf3dbb7b602b08fcfad0ba3a1142\">\n#top .av_textblock_section.av-mbqafqhu-b1e7cf3dbb7b602b08fcfad0ba3a1142 .avia_textblock{\ntext-align:justify;\n}\n<\/style>\n<section  class='av_textblock_section av-mbqafqhu-b1e7cf3dbb7b602b08fcfad0ba3a1142'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div>\n<div>\n<p style=\"font-weight: 400;\">It is a rule that every physics student learns: \u201cmetals cannot be electroluminescent.\u201d However, a team of researchers from several laboratories, including the IEMN, has just demonstrated that graphene, a material with metallic behavior, can emit light without heating up, a phenomenon previously thought to be exclusive to semiconductors. This unprecedented electroluminescence, observed in the infrared range, opens up new perspectives for more efficient and miniaturized light sources.<\/p>\n<p style=\"font-weight: 400;\">Electroluminescence refers to the emission of light induced by an electric current, without significant heat generation. It underpins many modern technologies, from flat-panel displays to laser diodes. Until now, this effect was believed to be limited to semiconductors and considered fundamentally inaccessible to metals.<\/p>\n<p style=\"font-weight: 400;\">In semiconductors, electrons can be excited into higher energy states, separated from lower-energy states by a bandgap. This energy can then be released as \u2018cold\u2019 light as seen in light-emitting diodes (LEDs). In contrast, metals lack such a bandgap: their electrons typically relax too rapidly, dissipating energy as heat and incandescent light, which renders electroluminescence impossible\u2026 or so we thought.<\/p>\n<p style=\"font-weight: 400;\">Graphene, a two-dimensional material consisting of a single layer of carbon atoms arranged in a honeycomb lattice, defies this expectation. Under specific conditions, it can exhibit electroluminescence. This breakthrough, published in <em>Nature<\/em>, relies on the use of ultra-high-quality graphene encapsulated in hexagonal boron nitride (hBN), which preserves the the material\u2019s\u00a0intrinsic and unusual electronic properties.<\/p>\n<\/div>\n<\/div>\n<div>\n<div><\/div>\n<\/div>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-7d81wh-4cf52abf94eba0774cf1b4992b02ffce\">\n@keyframes av_boxShadowEffect_av-7d81wh-4cf52abf94eba0774cf1b4992b02ffce-column {\n0%   { box-shadow:  0 0 0 0 #eaeaea; opacity: 1; }\n100% { box-shadow:  0 0 7px 0 #eaeaea; opacity: 1; }\n}\n.flex_column.av-7d81wh-4cf52abf94eba0774cf1b4992b02ffce{\nbox-shadow: 0 0 7px 0 #eaeaea;\npadding:10px 10px 10px 10px;\nbackground-color:#ffffff;\n}\n<\/style>\n<div  class='flex_column av-7d81wh-4cf52abf94eba0774cf1b4992b02ffce av_one_third  avia-builder-el-4  el_after_av_one_third  el_before_av_one_third  flex_column_div shadow-not-animated'     ><section  class='av_textblock_section av-mbqag0h1-b5c92c67b69f7ef7a29781515db0db58'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div>\n<div>\u00a0Graphene is a semi-metal with exceptionally mobile charge carriers that interact weakly with their environment. These electrons can reach highly non-equilibrium electronic states, far from thermal equilibrium. In this regime, the researchers observed infrared light emission consistent with electroluminescence, rather than mere incandescence. This makes graphene the first known metal-like material to exhibit electroluminescence.<\/div>\n<div>\n<p style=\"font-weight: 400;\">Beyond this light emission, the study reveals another key phenomenon: a remarkably efficient transfer of radiative energy between graphene and its substrate. Up to 70% of the energy dissipated by the electrical current is transferred to the substrate via electromagnetic interactions, particularly through the excitation of hyperbolic phonon-polaritons in hBN.<\/p>\n<p style=\"font-weight: 400;\">These quasi-particles, arising from the coupling of photons with vibrational modes in the crystal lattice, allow energy to propagate without relying on thermal conduction and therefore without significant heating.<\/p>\n<p style=\"font-weight: 400;\">This discovery challenges the conventional limits of electroluminescence and opens new avenues for designing light sources in the infrared domain, which is vital for telecommunications and sensing. Graphene\u2019s ability to emit light with minimal heating may pave the way for more efficient, compact optoelectronic devices, with promising applications in nanophotonics and ultra-miniaturized integrated light sources.<\/p>\n<\/div>\n<\/div>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-12z7zkx-515eb9c053f8a28edf8ae203b215e261\">\n.flex_column.av-12z7zkx-515eb9c053f8a28edf8ae203b215e261{\nbackground-color:#e2e2e2;\n}\n<\/style>\n<div  class='flex_column av-12z7zkx-515eb9c053f8a28edf8ae203b215e261 av_one_third  avia-builder-el-6  el_after_av_one_third  el_before_av_one_half  flex_column_div'     ><section  class='av_textblock_section av-r3om2p-53d68b68dcb2a4dfa235d643fe2feaa5'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div id=\"attachment_73994\" style=\"width: 550px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-73994\" class=\"wp-image-73994\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre.png\" alt=\"\" width=\"540\" height=\"540\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre.png 500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre-300x300.png 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre-80x80.png 80w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre-12x12.png 12w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre-36x36.png 36w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/06\/Design-sans-titre-180x180.png 180w\" sizes=\"auto, (max-width: 540px) 100vw, 540px\" \/><\/a><p id=\"caption-attachment-73994\" class=\"wp-caption-text\">Graphene electroluminescence illustration generated by DALL\u00b7E. @Credit: PhD thesis of Aur\u00e9lien Schmitt (2023)<\/p><\/div>\n<div><\/div>\n<hr \/>\n<div>\n<div>This work is the result of a collaboration between the <a href=\"https:\/\/www.lpens.ens.psl.eu\/\">Laboratoire de Physique de l&rsquo;\u00c9cole normale sup\u00e9rieure (LPENS)<\/a>, <a href=\"https:\/\/www.institutoptique.fr\/\">the Institut Langevin, the Institut d&rsquo;Optique de Palaiseau<\/a>, <a href=\"https:\/\/www.universite-lyon.fr\/comue-universite-de-lyon-site-academique-lyon-saint-etienne-791.kjsp\">the University of Lyon<\/a> and <a href=\"https:\/\/www.groupe-insa.fr\/\">INSA<\/a>, with the participation of David Mele, now a lecturer at <a href=\"https:\/\/www.junia.com\/fr\/\">JUNIA<\/a> and a researcher at the IEMN, a laboratory also affiliated with this publication.<\/div>\n<\/div>\n<\/div><\/section><\/div><\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-mbqcfppn-a2f6a7b71c2394ea3cd4b633354cb2c6\">\n@keyframes av_boxShadowEffect_av-mbqcfppn-a2f6a7b71c2394ea3cd4b633354cb2c6-column {\n0%   { box-shadow:  0 0 0 0 ; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 ; opacity: 1; }\n}\n.flex_column.av-mbqcfppn-a2f6a7b71c2394ea3cd4b633354cb2c6{\nbackground-color:#f2f2f2;\n}\n<\/style>\n<div  class='flex_column av-mbqcfppn-a2f6a7b71c2394ea3cd4b633354cb2c6 av_one_half  avia-builder-el-8  el_after_av_one_third  el_before_av_one_half  first flex_column_div  column-top-margin'     ><section  class='av_textblock_section av-mbqcfcxb-e5e8764597273f521ab542d086a1a8ad'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div>\n<blockquote>\n<p><span style=\"text-decoration: underline;\">R\u00e9f\u00e9rence<\/span>:<\/p>\n<p>Electroluminescence and energy transfer mediated by hyperbolic polaritons, <a href=\"https:\/\/www.nature.com\/articles\/s41586-025-08627-6#auth-Loubnan-Abou_Hamdan-Aff1-Aff2\">Loubnan Abou-Hamdan<\/a> et al, Nature 639, 909 (2025) ;<\/p>\n<p><a href=\"https:\/\/doi.org\/10.1038\/s41586-025-08627-6\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1038\/s41586-025-08627-6<\/a><\/p>\n<\/blockquote>\n<\/div>\n<div><\/div>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-2r69a9-40f33cd5e1f59b1815bc9ee1e0374d4d\">\n@keyframes av_boxShadowEffect_av-2r69a9-40f33cd5e1f59b1815bc9ee1e0374d4d-column {\n0%   { box-shadow:  0 0 0 0 #c9c9c9; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 #c9c9c9; opacity: 1; }\n}\n.flex_column.av-2r69a9-40f33cd5e1f59b1815bc9ee1e0374d4d{\nbox-shadow: 0 0 10px 0 #c9c9c9;\nborder-radius:15px 15px 15px 15px;\nbackground-color:#f2f2f2;\n}\n<\/style>\n<div  class='flex_column av-2r69a9-40f33cd5e1f59b1815bc9ee1e0374d4d av_one_half  avia-builder-el-10  el_after_av_one_half  avia-builder-el-last  flex_column_div shadow-not-animated  column-top-margin'     ><section  class='av_textblock_section av-mbqcj3p8-f6fdd10e7545f9c47cd3fb670933c961'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><blockquote>\n<p><span style=\"text-decoration: underline;\">Contact:<\/span><\/p>\n<p>david.mele<a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/05\/arobase6.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-73335 alignnone\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/05\/arobase6.png\" alt=\"\" width=\"16\" height=\"14\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/05\/arobase6.png 16w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2025\/05\/arobase6-14x12.png 14w\" sizes=\"auto, (max-width: 16px) 100vw, 16px\" \/><\/a>junia.com<\/p>\n<\/blockquote>\n<\/div><\/section><\/div>","protected":false},"excerpt":{"rendered":"","protected":false},"author":20,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[297],"tags":[],"class_list":["post-74008","post","type-post","status-publish","format-standard","hentry","category-newsletter"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/74008","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=74008"}],"version-history":[{"count":8,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/74008\/revisions"}],"predecessor-version":[{"id":74480,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/74008\/revisions\/74480"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=74008"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=74008"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=74008"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}