Tunable White Fluorescent Copper Gallium Sulfide Quantum Dots Enabled by Mn Doping

Abstract

Fluorescence of semiconductor quantum dots (QDs) can be tuned by engineering the band gap via size and composition control and further doping them with impurity ions. Targeting on highly bright white-emissive I-III-VI -type copper gallium sulfide (Cu-Ga-S, CGS) host QDs with the entire visible spectral coverage of blue to red, herein, Mn(2+) ion doping, through surface adsorption and lattice diffusion is fulfilled. Upon doping a distinct Mn emission from (4)T1-(6)A1 transition successfully appears in white photoluminescence (PL) of undoped CGS/ZnS core/shell QDs and with varying Mn concentration a systematic white spectral evolution of CGS:Mn/ZnS QDs is achievable with high PL quantum yield retained. The origins of white PL of CGS:Mn/ZnS QDs that is well decomposed into three emission bands are appropriately assigned. The resulting single-phased, doped QDs are then employed as near-UV-to-white down converters for the fabrication of white light-emitting diodes (LEDs). Electroluminescent properties of white QD-LEDs depending on Mn concentration of CGS:Mn/ZnS QDs and forward current are also discussed in detail.

Dual-Emissive and Color-Tunable Mn-Doped InP/ZnS Quantum Dots via a Growth-Doping Method

“…Doped semiconductor QDs have also been widely investigated due to their unique optical properties [ 3 – 8 ]. The PL of QDs can be tailored by doping impurity ions, while their absorption bands remain unchanged.…”

Engineering Bicolor Emission in 2D Core/Crown CdSe/CdSe1–xTex Nanoplatelet Heterostructures Using Band-Offset Tuning

“…They rely on QDs heterostructure 6,7 and on doped QDs. 8,9 In particular, the observation of a phosphorescence signal from Mn doped NCs have been extensively studied. 10 However, in most of these reports, the two PL efficiencies are very different which prevent their use as phosphor for display.…”

Effective Mn-Doping in AgInS2/ZnS Core/Shell Nanocrystals for Dual Photoluminescent Peaks

“…To identify the PL components, we attempted to measure the time-resolved PL lifetimes of our AIS-based NCs. Generally, the semiconductor NCs show typically fast PL lifetimes with few hundreds of nanoseconds, whereas the Mn emission corresponds to the d-d transition ( 4 T 1 → 6 A 1 ) within the Mn d multiplets, leading to long lifetimes in the range of several hundreds of microseconds [50,51]. We measured the PL decay curves of AIS NCs and AIS/ZnS NCs at the PL wavelength of 608 nm and 538 nm, respectively, as shown in Figure 2b.…”