Bright Blue Emitting Cu-doped Cs2ZnCl4 Colloidal Nanocrystals
2020
We report here the synthesis
of undoped and Cu-doped Cs2ZnCl4 nanocrystals (NCs), in
which we could tune the concentration of Cu from 0.7% to 7.5%. According to electron
paramagnetic resonance analysis, in 0.7% and 2.1% Cu-doped NCs the Cu ions were
present in the +1 oxidation state only, while in NCs at higher Cu
concentrations we could detect Cu(II) ions. The undoped Cs2ZnCl4
NCs were non emissive, while the Cu-doped samples had a bright intra-gap photoluminescence
(PL) at 2.6eV mediated by band-edge absorption. The PL quantum yield was maximum (~55%) for the samples with low Cu concentration (≤ 2.1%) and it systematically
decreased when further increasing the concentration of Cu, reaching 15%
for the NCs with the highest doping level (7.5%). Density functional theory calculations indicated that the
PL emission could be ascribed only to Cu(I) ions: these ions introduce intra-gap
states that promote the formation of
self-trapped excitons, through which an efficient emission takes place.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
0
Citations
NaN
KQI