Fig. 1. (a) Structural design and (b) the corresponding energy level diagram of the Tr-QLEDs fabricated in this study [22]. Performance of the fabricated Tr-QLED device: (c) luminance–voltage (L–V) characteristics, (d) current density–voltage (J–V) characteristics, and (e) current efficiency and (f) EQE as functions of current density.

Fig. 2. (a) Current density–voltage (J–V) curves of the electron-only device with and without ZnMgO. Energy-level diagram of the materials and the corresponding working mechanisms of the electron-only devices (b) without and (c) with ZnMgO. (d)–(g) EL spectra of the fabricated Tr-QLEDs device with and without ZnMgO driven by different voltages.

Fig. 3. Bottom, top, and total emission characteristics of Tr-QLEDs without and with a ZnMgO layer: (a) and (b) luminance-voltage (L-V), (c) and (d) current efficiency, (e) and (f) EQE as a function of current density.

Fig. 4. (a) EL spectra, (b) CIE chromaticity diagram, and (c) transmittance spectra of the fabricated Tr-QLEDs with double ETLs. The inset of (c) shows images of the device at turn-off and turn-on states. (d) Photograph of the Tr-QLED in the front of a mirror.

Table 1. EL Characteristics of Tr-QLEDs with Different ETLs

Table 2. Comparison of the Characteristics and Performances of Reported Tr-QLEDs