Schematic illustration of a thin-film LED composed with a ZnO NC EML and a pentacene HTL.
Typical FESEM surface image of ZnO NC layer printed on a quartz substrate.
XRD pattern of a commercial wurtzite ZnO powder (a) and those of the ZnO NC powders as a function of (b). XRD patterns are offset for clarity.
Time evolutions of crystal size: the average crystal radius cubed of ZnO NCs plotted vs . The solid and dashed lines show the fit of the results to Eq. (2).
PL spectra of the ZnO NCs as a function of (a) and PL peak intensities of UV (●) and green (◆) bands, respectively, plotted vs (b).
PL peak energies of exciton emission (●) plotted as a function of . Those reported in Ref. 30 are also plotted (◼).
characteristics of thin-film LEDs using ZnO NC EMLs with different (8 nm: ●, 9 nm: ◆, and 11 nm: ▲) (a) and its expanded plot in light-emitting region (b). The inset in (a) shows EL intensities plotted vs as a function of (8 nm: ●, 9 nm: ◆, and 11 nm: ▲). Solid lines in (a) represents asymptotic lines to the power laws.
Optical transmittance spectrum of a pentacene HTL deposited on a quartz substrate (a) and EL spectra of thin-film LEDs with ZnO NC EMLs with different (b) [8 nm (top), 9 nm (middle), and 11 nm (bottom)]. The spectra are offset for clarity. The EL spectra were measured near their maximum intensities as shown in the inset of Fig. 7(a).
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