Quantitative electrochemical control over optical gain in colloidal quantum-dot and quantum-well solids

Jaco J. Geuchies, Baldur Brynjarsson, Gianluca Grimaldi, Indy Du Fossé, Robbert Dijkhuizen, Marijn Koel, Solrun Gudjonsdottir, Ward Van Der Stam, Wiel H. Evers, Pieter Geiregat, Arjan J. Houtepen, More Authors

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

2 Citations (Scopus)

Abstract

Solution processed quantum dot (QD) lasers are one of the holy-grails of nanoscience. They are not yet commercialized because the lasing threshold is too high: one needs < 1 exciton per QD, which is hard to achieve due to fast non-radiative Auger recombination. The threshold can however be reduced by electronic doping of the QDs, which decreases the absorption near the band-edge, such that the stimulated emission (SE) can easily outcompete absorption. Here, we show that by electrochemically doping films of CdSe/CdS/ZnS QDs we achieve quantitative control over the gain threshold. We obtain stable and reversible doping more than two electrons per QD. We quantify the gain threshold and the charge carrier dynamics using ultrafast spectroelectrochemistry and achieve quantitative agreement between experiments and theory, including a vanishingly low gain threshold for doubly doped QDs. Over a range of wavelengths with appreciable gain coefficients, the gain thresholds reach record-low values of ∼10-5 excitons per QD. These results demonstrate an unprecedented level of control over the gain threshold in doped QD solids, paving the way for the creation of cheap, solution-processable low-threshold QD-lasers.

Original languageEnglish
Title of host publicationProceedings of SPIE
Subtitle of host publicationPhysical Chemistry of Semiconductor Materials and Interfaces XIX
EditorsChristian Nielsen, Daniel Congreve, Andrew J. Musser
PublisherSPIE
Number of pages20
Volume11464
ISBN (Electronic)9781510637344
DOIs
Publication statusPublished - 2020
EventPhysical Chemistry of Semiconductor Materials and Interfaces XIX 2020 - Virtual, Online, United States
Duration: 24 Aug 20204 Sep 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume11464
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferencePhysical Chemistry of Semiconductor Materials and Interfaces XIX 2020
CountryUnited States
CityVirtual, Online
Period24/08/204/09/20

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