The photoluminescence stability of all-inorganic perovskite nanocrystals (CsPbBr3) with different size is studied.

Novel white light emitting diodes (LEDs) with environmentally friendly dual emissive quantum dots (QDs) as single color-converters are one of the most promising high-quality solid-state lighting sources for meeting the growing global demand for resource sustainability. A facile method was developed for the synthesis of the bright green-red-emitting Mn and Cu codoped Zn-In-S QDs with an absorption bangdgap of 2.56 eV (485 nm), a large Stokes shift of 150 nm, and high emission quantum yield up to 75%, which were suitable for warm white LEDs based on blue GaN chips. The wide photoluminescence (PL) spectra composed of Cu-related green and Mn-related red emissions in the codoped QDs could be controlled by varying the doping concentrations of Mn and Cu ions. The energy transfer processes in Mn and Cu codoped QDs were proposed on the basis of the changes in PL intensity and lifetime measured by means of steady-state and time-resolved PL spectra. By integrating these bicolor QDs with commercial GaN-based blue LEDs, the as-fabricated tricolor white LEDs showed bright natural white light with a color rendering index of 95, luminous efficacy of 73.2 lm/W, and color temperature of 5092 K. These results indicated that (Mn,Cu):Zn-In-S/ZnS QDs could be used as a single color-converting material for the next generation of solid-state lighting.

We report the fabrication of efficient white light-emitting diodes (WLEDs) based on Cu : ZnInS/ZnS core/shell quantum dots (QDs) with super large Stokes shifts. The composition-controllable Cu : ZnInS/ZnS QDs with a tunable emission from deep red to green were prepared by a one-pot noninjection synthetic approach. The high performance Cu : ZnInS QD-WLEDs with the colour rendering index up to 96, luminous efficacy of 70-78 lm W(-1), and colour temperature of 3800-5760 K were successfully fabricated by integration of red and green Cu-doped QDs. Negligible energy transfer between Cu-doped QDs was clearly found by measuring the photoluminescence lifetimes of the QDs, consistent with the small spectral overlap between QD emission and absorption. The experimental results indicated low toxic Cu : ZnInS/ZnS QDs could be suitable for solid state lighting.

The enhanced luminescence of Mn2+ in Mn2+:CsPbCl3−xBrx NCs is related to Br composition-dependent energy transfer from excitons to Mn2+.

The Mn2+-doped CsPbCl3 nanocrystals (NCs) with a low Mn2+ doping concentration were synthesized using different reaction temperatures to control the NC size from 5.3 to 17.4 nm and then were studied by means of steady-state and time-resolved photoluminescence (PL) spectroscopy at various temperatures. The Mn2+ emissions with different quantum yields in the doped NCs in hexane exhibited nearly size-independent and single-exponential decay lifetimes of 1.8 ms at room temperature. The PL lifetimes in all Mn2+ in CsPbCl3-doped NCs had similar temperature dependence from 80 to 300 K, whereas they were size-dependent at elevated temperatures, reflecting thermal degradation of doped NCs. The degradation mechanisms of Mn2+ PL were attributed to the amount of surface defects as nonradiative recombination centers generated in size-unchanged and grown Mn2+:CsPbCl3 NCs. The study provides the detailed understanding of the thermal degradation mechanisms in doped perovskite NCs for optoelectronic applications.

The photoluminescence (PL) properties of the Cu:Zn-In-S core quantum dots (QDs) and core-shell QDs were systematically investigated by using steady-state and time-resolved PL spectra at temperatures ranging from 80 to 400 K. The effects of the shell structure and the host bandgap on the thermal stability of Cu dopant emissions were studied by measuring the change in the PL intensity and the lifetime. It was found that the PL intensities and lifetimes of the core and core/shell QDs with green, yellow, and red emissions almost decrease with increasing temperatures while their PL was quenched at 300 K and 400 K, respectively, indicating the shell-enhanced thermal stability of the PL. The emission wavelength of the QDs as a function of temperature was also provided. The mechanisms of Cu dopant emission and thermal quenching were discussed. Finally, the green, yellow, red, and white light emitting light emitting diodes (LEDs) were fabricated based on Cu:Zn-In-S QDs.

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We have demonstrated organic light-emitting diodes (OLEDs) by incorporating copper iodide (CuI) in 4,4′,4′′-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (m-MTDATA) as a hole injection layer (HIL) based on the emitting system of C545T–Alq3.