Sub–single-exciton lasing using charged quantum dots coupled to a distributed feedback cavity

Abstract

Colloidal semiconductor quantum dots (QDs) are attractive materials for realizing highly flexible, solution-processable optical gain media, but they are difficult to use in lasing because of complications associated with extremely short optical-gain lifetimes limited by nonradiative Auger recombination. By combining compositional grading of the QD’s interior for hindering Auger decay with postsynthetic charging for suppressing parasitic ground-state absorption, we can reduce the lasing threshold to values below the single-exciton-per-dot limit. As a favorable departure from traditional multi-exciton–based lasing schemes, our approach should facilitate the development of solution-processable lasing devices and thereby help to extend the reach of lasing technologies into areas not accessible with traditional, epitaxially grown semiconductor materials.

Surface passivation extends single and biexciton lifetimes of InP quantum dots

“…Colloidal quantum-conned nanocrystals, especially spherical quantum dots (QDs), can exhibit a broad tunability of their band-gaps, multiexciton lifetimes and band-edge positions by simply varying the particle sizes, 1,2 enabling their applications in lasing, 3,4 light-emitting diodes (LEDs), [5][6][7] and solar fuel generation. [8][9][10][11] In the past few decades, Cd and Pb-based chalcogenide nanocrystals (e.g., CdSe 3,4 and PbSe 12 ) have been widely investigated, leading to signicant advancement of our fundamental understanding of exciton and carrier dynamics of QDs and how these properties can be optimized through size, shape and composition control of QDs and heterostructures to improve their device performances. 2,13,14 However, the toxic heavy metals in Cd-and Pb-based QDs pose potential human health risks, hindering their commercial applications.…”

Facet Control for Trap‐State Suppression in Colloidal Quantum Dot Solids

“…Colloidal quantum dots (QDs) are promising semiconductor materials, due to their size‐tunable bandgap, solution processability, and adjustable surface chemistry, [ 1 ] for applications in devices including light‐emitting diodes, [ 2–3 ] photodetectors, [ 4 ] lasers, [ 5 ] transistors, [ 6 ] and solar cells. [ 7 ] With the significant progress in synthesis, ligand exchange, and device structure, the performance of PbS QD solar cells has been improved rapidly, achieving a certified power conversion efficiency (PCE) of 12.3%.…”

Electrical control of single-photon emission in highly charged individual colloidal quantum dots

“…The observation of reduced Auger recombination, leading to an increased quantum yield of colloidal quantum dots, has sparked a fast-paced progress in the development of highly fluorescent and stable quantum dots for displays (1), light-emitting diodes (LEDs) (2), and coherent (3) and quantum light sources (4,5). Still, in the colloidal quantum dot community, there is an ongoing struggle to reconcile suppressed Auger recombination with fast radiative recombination (6).…”