Altintas, YemlihaGungor, KivancGao, YuanSak, MustafaQuliyeva, UlviyyaBappi, GolamMutlugun, EvrenSargent, Edward H.Demir, Hilmi Volkan2021-03-182021-03-1820191936-08511936-086XPubMed ID: 31436957https://doi.org/10.1021/acsnano.9b04967https://hdl.handle.net/20.500.12573/595The authors gratefully acknowledge financial support from the Singapore National Research Foundation under the programs of NRF-NRFI2016-08 and the Science and Engineering Research Council, Agency for Science, Technology and Research (A*STAR) of Singapore, and also partially from TUBITAK 115E679 and 117E713. H.V.D. acknowledges support from TUBA. E.M. acknowledges support from TUBA-GEBIP, and E.M. and Y.A. also acknowledge funding from Abdullah Gul University Scientific Research Project No. FDK-2017-96. K.G. and M.S. acknowledge support from TUBITAK BIDEB 2211 program. We further acknowledge Mr. Mustafa Guler for his assistance in TEM imaging.As an attractive materials system for high- Record-low optical gain threshold in giant-shell COWs performance optoelectronics, colloidal nanoplatelets (NPLs) benefit from atomic-level precision in thickness, minimizing emission inhomogeneous broadening. Much progress has been made to enhance their photoluminescence quantum yield (PLQY) and photostability. However, to date, layer-by-layer growth of shells at room temperature has resulted in defects that limit PLQY and thus curtail the 0.2 performance of NPLs as an optical gain medium. Here, we introduce a hot-injection method growing giant alloyed shells using an approach that reduces core/shell lattice mismatch and suppresses Auger recombination. Near-unity PLQY is achieved with a narrow full-width-at-half-maximum (20 nm), accompanied by emission tunability (from 610 to 650 nm). The biexciton lifetime exceeds 1 ns, an order of magnitude longer than in conventional colloidal quantum dots (CQDs). Reduced Auger recombination enables record-low amplified spontaneous emission threshold of 2.4 mu J cm(-2) under one-photon pumping. This is lower by a factor of 2.5 than the best previously reported value in nanocrystals (6 /kJ cm(-2) for CdSe/CdS NPLs). Here, we also report single-mode lasing operation with a 0.55 mu J cm(-2) threshold under two-photoexcitation, which is also the best among nanocrystals (compared to 0.76 mu J cm(-2) from CdSe/CdS CQDs in the Fabry-Perot cavity). These findings indicate that hot-injection growth of thick alloyed shells makes ultrahigh performance NPLs.enginfo:eu-repo/semantics/openAccessVCSELsingle-mode lasingoptical gainhot-injection growthnanoplateletscolloidal quantum wellsarticleVolume: 1391066210670