AgGaS2/Ga2S3 quantum dots exhibiting efficient narrow blue emission

Abstract

Ternary metal chalcogenide quantum dots (QDs) have become an important class of materials characterised by a large tunability of the band gap and hence spectral range of light absorption and emission by changing their composition and size. They are an appealing alternative to toxic Cd-based NCs and offer a simpler synthetic process compared to III–V QDs such as InP or InAs. However, in the blue region, they typically exhibit broad emission peaks and low photoluminescence quantum yield (PLQY). Herein, we report AgGaS₂/Ga₂S₃ core–shell QDs emitting in the deep-blue region at 442 nm, and exhibiting a narrow line width (FWHM = 24 nm) as well as a PLQY exceeding 50% on passivation of defect states through treatment with tributylphosphine.