Laser-induced doping and fine patterning of massively prepared luminescent ZnS nanospheres

Abstract

The laser-induced doping and fine patterning of luminescent ZnS nanospheres is reported. Monodispersive ZnS nanospheres were synthesized in a large scale (gram-quantity) by a low temperature (70 °C) aqueous method following a self-aggregation and size-limiting process. The nanospheres were in a narrow (60–80 nm) diameter distribution and were formed by aggregated nanocrystals (∼4 nm in diameter). Laser-induced doping to obtain luminescent patterns was realized by performing a laser irradiation (wavelength: 1064 nm) on the films of nanospheres mixed with dopant precursors (i.e. MnCl₂ or AlCl₃). Patterns on both the flat and highly curved substrates were fabricated. Fine luminescent microarrays with sizes of ∼15 μm were fabricated by further performing a laser-induced “peel-off” on the doped films. Single-element (Mn) doping and dual-element (Al–Cl) co-doping were demonstrated. Strong photoluminescence spectra centered at ∼590 nm and ∼513 nm were attained from the Mn doped and Al–Cl co-doped patterns, respectively, while the corresponding cathodoluminescence revealed a slight blue shift. The formation of a donor–acceptor pair was proposed to interpret the luminescence intensity enhancement of the featured Al–Cl co-doped ZnS. This work provides an approach to produce fine luminescent patterns for application in high resolution displays, multi-color light emitting diodes and X-ray imaging.