Mn doped AZIS/ZnS nanocrystals (NCs): Effects of Ag and Mn levels on NC optical properties

Abstract

In this work, Mn-doped AZIS/ZnS NCs were prepared using a nucleation doping approach with the tuning of Mn and Ag levels in their synthesis. The optical properties of Mn:AZIS/ZnS NCs are found to be significantly affected by Ag and Mn levels. Specifically, more Ag and Mn atoms in Mn:AZIS/ZnS NCs cause their fluorescence red-shift, and as the Ag or Mn level reaches a high threshold, the fluorescence lifetime of Mn:AZIS/ZnS NC has a significant drop. The reasons for the effects of Mn and Ag levels on NC optical properties were explored and discussed. Through this study, it is also found that with certain Ag and Mn levels in synthesis, some Mn:AZIS/ZnS NCs present optimal optical properties including high brightness (QY > 40%), long fluorescence lifetime (> 1.2 ms), low energy for excitation (excitable at 405 nm), and no reabsorption. The feasibility of the optimized NCs for time-gated fluorescence measurement using a portable/compact instrument was further demonstrated, which indicates the application potential of the NCs in time-gated biosensing including point-of-care testing. Notably, this study also discloses that Mn:AZIS/ZnS NCs with different lifetimes can be achieved by tuning Mn and Ag levels in synthesis, which may further broaden the applications of Mn:AZIS/ZnS NCs in multiplexing detection/measurement.

Optical Properties of Mn-Doped CuGa(In)S-ZnS Nanocrystals (NCs): Effects of Host NC and Mn Concentration

“…Note that the interaction would cause the further decrease of the lifetime (both the short lifetime and the long lifetime). The long lifetime is thought be due to the relatively isolated Mn dopants in the NCs [ 31 , 46 , 47 ]. The number of relatively isolated Mn dopants could be reduced with the incorporation of more Cu atoms into the host NCs, which would result in the decrease in the long lifetime.…”

Review of Mn-Doped Semiconductor Nanocrystals for Time-Resolved Luminescence Biosensing/Imaging

“…For such NCs, the origin of the short lifetime τ 1 of these NCs is still under debate. According to the literature, [113][114][115][116]119 the short lifetime τ 1 could result from Mn−Mn coupling or the interaction of Mn with the host lattice field. Its related magnitude (A 1 ) should indicate the degree of the interaction of between Mn and Mn or between Mn and the host NC.…”

“…Zaeimian et al developed Mn-doped AgZnInS/ZnS NCs and investigated how the NC luminescence properties were affected by the Ag and Mn levels in NCs . The researchers used the nucleation-doping approach.…”

A Highly Sensitive Time-Gated Fluorescence Immunoassay Platform Using Mn-Doped AgZnInS/ZnS Nanocrystals as Signal Transducers

“…The Mn:AgZnInS/ZnS NCs were synthesized according to our previous report [ 19 ]. In the first step, Mn:AgZnInS were synthesized by using 0.2 mmol Zn precursor, 0.2 mmol In precursor, 0.025 mmol Mn precursor, 0.8 mmol sulfur precursor, and 0.05 mmol Ag precursor.…”

“…In spite of these merits, some recent works on Mn doping into I(II)-III-VI NCs show significant variations on their absorption/fluorescence spectra and lifetimes (hundreds of nanoseconds to milliseconds) of the doped NCs depending on the synthesis approaches/conditions [ 17 , 18 ]. Recognizing that the electronic energy bands of the host NCs could interact with the energy levels of Mn dopants and thus determine the optical properties of Mn-doped quaternary NCs [ 15 , 19 ], we have specifically investigated the interaction between Mn dopants and host AgZnInS/ZnS NCs by tuning host composition and also changing Mn spatial distribution and its concentration in host NCs [ 19 ]. Therefore, we achieved Mn-doped AgZnInS/ZnS (Mn:AgZnInS/ZnS) NCs with optimal optical properties, including long fluorescence lifetimes (1.33 milliseconds), low excitation energy (excitable at 405 nm wavelength), minimal emission reabsorption, and adequate brightness (>40% quantum yield).…”