Altintas, YemlihaQuliyeva, UlviyyaGungor, KivancErdem, OnurKelestemur, YusufMutlugun, EvrenDemir, Hilmi Volkan2025-09-252025-09-2520191613-68101613-6829https://doi.org/10.1002/smll.201804854https://hdl.handle.net/20.500.12573/3942Kelestemur, Yusuf/0000-0003-1616-2728; Demir, Hilmi Volkan/0000-0003-1793-112X; Gungor, Kivanc/0000-0002-4628-0197; Erdem, Onur/0000-0003-2212-965X; Mutlugun, Evren/0000-0003-3715-5594Colloidal semiconductor nanoplatelets (NPLs) offer important benefits in nanocrystal optoelectronics with their unique excitonic properties. For NPLs, colloidal atomic layer deposition (c-ALD) provides the ability to produce their core/shell heterostructures. However, as c-ALD takes place at room temperature, this technique allows for only limited stability and low quantum yield. Here, highly stable, near-unity efficiency CdSe/ZnS NPLs are shown using hot-injection (HI) shell growth performed at 573 K, enabling routinely reproducible quantum yields up to 98%. These CdSe/ZnS HI-shell hetero-NPLs fully recover their initial photoluminescence (PL) intensity in solution after a heating cycle from 300 to 525 K under inert gas atmosphere, and their solid films exhibit 100% recovery of their initial PL intensity after a heating cycle up to 400 K under ambient atmosphere, by far outperforming the control group of c-ALD shell-coated CdSe/ZnS NPLs, which can sustain only 20% of their PL. In optical gain measurements, these core/HI-shell NPLs exhibit ultralow gain thresholds reaching approximate to 7 mu J cm(-2). Despite being annealed at 500 K, these ZnS-HI-shell NPLs possess low gain thresholds as small as 25 mu J cm(-2). These findings indicate that the proposed 573 K HI-shell-grown CdSe/ZnS NPLs hold great promise for extraordinarily high performance in nanocrystal optoelectronics.eninfo:eu-repo/semantics/openAccessCore/Shell NanocrystalsHot-Injection GrowthNanoplateletsOptical GainSemiconductor NanocrystalsStabilityArticle10.1002/smll.2018048542-s2.0-85061001564