Enhanced photoluminescence quantum yield of red-emitting CdTe:Gd³⁺ QDs for WLEDs applications

In order to improve the quantum yield of red-emitting CdTe quantum dots (QDs), CdTe:Gd³⁺ QDs were synthesized by a facile one-step aqueous method. The composition, morphology, and photoluminescence property of CdTe:Gd³⁺ QDs were characterized. The results show that the doping of Gd³⁺ not only leads to a red-shift in the emission wavelength but also improves the photoluminescence quantum yield (PL QY) of CdTe QDs up to 85.74%. Doping of Gd element causes the Te dangling bond on the surface of CdTe QDs to be destroyed, thus reducing the nonradiative surface recombination, which is considered to be the reason of the increase in PL QY of CdTe QDs. Finally, high color rendition white light was generated from the CdTe:Gd³⁺ QDs-assisted phosphor-converted white light-emitting diode (WLED). Under operation of 50 mA forward bias current, the fabricated WLED emitted bright warm white light with a high color rendering index of 86, a low correlated color temperature (CCT) of 4020 K, a suitable Commission Internationale de l’Eclairage color coordinates of (0.3651, 0.3223), and an enhanced luminous efficiency of 68.52 lm/W.