Ultranarrow and widely tunable Mn²⁺-induced photoluminescence from single Mn-doped nanocrystals of ZnS-CdS alloys

Abstract

Extensively studied Mn-doped semiconductor nanocrystals have invariably exhibited photoluminescence over a narrow energy window of width ≤150 meV in the orange-red region and a surprisingly large spectral width (≥180  meV), contrary to its presumed atomic-like origin. Carrying out emission measurements on individual single nanocrystals and supported by ab initio calculations, we show that Mn PL emission, in fact, can (i) vary over a much wider range (~370 meV) covering the deep green—deep red region and (ii) exhibit widths substantially lower (~60–75  meV) than reported so far, opening newer application possibilities and requiring a fundamental shift in our perception of the emission from Mn-doped semiconductor nanocrystals.