{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:44:37Z","timestamp":1760150677387,"version":"build-2065373602"},"reference-count":32,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,12,22]],"date-time":"2023-12-22T00:00:00Z","timestamp":1703203200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NSF ECCS","award":["2132098"],"award-info":[{"award-number":["2132098"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>Transition metal dichalcogenides (TMDs) have unique absorption and emission properties that stem from their large excitonic binding energies, reduced-dielectric screening, and strong spin\u2013orbit coupling. However, the role of substrates, phonons, and material defects in the excitonic scattering processes remains elusive. In tungsten-based TMDs, it is known that the excitons formed from electrons in the lower-energy conduction bands are dark in nature, whereas low-energy emissions in the photoluminescence spectrum have been linked to the brightening of these transitions, either via defect scattering or via phonon scattering with first-order phonon replicas. Through temperature and incident-power-dependent studies of WS2 grown by CVD or exfoliated from high-purity bulk crystal on different substrates, we demonstrate that the strong exciton\u2013phonon coupling yields brightening of dark transitions up to sixth-order phonon replicas. We discuss the critical role of defects in the brightening pathways of dark excitons and their phonon replicas, and we elucidate that these emissions are intrinsic to the material and independent of substrate, encapsulation, growth method, and transfer approach.<\/jats:p>","DOI":"10.3390\/nano14010037","type":"journal-article","created":{"date-parts":[[2023,12,22]],"date-time":"2023-12-22T04:44:40Z","timestamp":1703220280000},"page":"37","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Observation of Multi-Phonon Emission in Monolayer WS2 on Various Substrates"],"prefix":"10.3390","volume":"14","author":[{"given":"Eli R.","family":"Adler","sequence":"first","affiliation":[{"name":"Department of Physics, Georgetown University, Washington, DC 20057, USA"},{"name":"U.S. Army Combat Capabilities Development Command, Army Research Laboratory, Adelphi, MD 20783, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thy Doan Mai","family":"Le","sequence":"additional","affiliation":[{"name":"Department of Physics, Georgetown University, Washington, DC 20057, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ibrahim","family":"Boulares","sequence":"additional","affiliation":[{"name":"U.S. Army Combat Capabilities Development Command, Army Research Laboratory, Adelphi, MD 20783, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Robert","family":"Boyd","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5518-5087","authenticated-orcid":false,"given":"Yangchen","family":"He","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"Rhodes","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8348-7587","authenticated-orcid":false,"given":"Edward","family":"Van Keuren","sequence":"additional","affiliation":[{"name":"Department of Physics, Georgetown University, Washington, DC 20057, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4151-262X","authenticated-orcid":false,"given":"Paola","family":"Barbara","sequence":"additional","affiliation":[{"name":"Department of Physics, Georgetown University, Washington, DC 20057, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sina","family":"Najmaei","sequence":"additional","affiliation":[{"name":"U.S. Army Combat Capabilities Development Command, Army Research Laboratory, Adelphi, MD 20783, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"021001","DOI":"10.1103\/RevModPhys.90.021001","article-title":"Colloquium: Excitons in atomically thin transition metal dichalcogenides","volume":"90","author":"Wang","year":"2018","journal-title":"Rev. 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