Super-Eg excitation wavelength dependent Zni-VO complex defects related characteristic
emissions of green, yellow, and orange-red from ZnO QDs are completely inhibited by reducing
oxygen vacancies through the hybridization of Zn interstitials in ZnO QDs with antibonding O-
states of graphene oxide (GO) QDs. Only λex independent violet-purple-blue (V-P-B)
emission resulting from transitions among Frenkel pairs (Zni0-VZn) and the defects Zni0-Oi in ZnO-
GO QDs is successfully achieved. White-light emission from PL QD-LEDs is achieved using a mixture of yellow emissive ZnO and blue emissive ZnO-GO QDs with CIE (0.32, 0.34) excited by a UV LEDs chip (λ = 365 nm). Further, ZnO-GO QD-based deep-blue LEDs (λ = 438 nm) with luminance of 1980 cd/m2, a luminous efficacy (LE) of 2.53 cd/A, and external quantum efficiency (EQE) of 2.78% with CIE (0.16, 0.11) are also realized.
|