Emission-tunable Mn-doped ZnS/ZnO heterostructure nanobelts for UV-pump WLEDs

The development of emission-tunable structures opens an optimistic future for white light-emitting diodes (WLED) utilizing a UV pump. Herein, we report emission-tunable Mn-doped ZnS/ZnO heterostructure nanobelts synthesized by the thermal evaporation method, following by an appropriate oxidation process. Under the UV excitation of 330 nm, the as-received nanobelts show an orange-yellow light with CCT of 3056 K, the 500 and 700 degrees C-oxidized samples strongly exhibit a warm white light emission with CCT of 3393 K and 3551 K, respectively. Surprisingly, the Mn-doped ZnS/ZnO heterostructures oxidized at 600 degrees C show a white light emission with CIE chromaticity coordinate of (0.31, 0.39) and CCT value of 6290 K, which are nearly very close to that of the commercial YAG:Ce3+ phosphor. A prototype WLED with the color coordinates of (0.33, 0.45), the CCT of 5491 K, and the QE similar to 61% was successfully fabricated using Mn-doped ZnS/ZnO heterostructure nanobelts coated on the surface of UV (370 nm) chip. The obtained Mn-doped ZnS/ZnO heterostructures are promising to be applied in UV-pumped WLED fabrication.

Automated summary

A new emission-tunable Mn-doped ZnS/ZnO heterostructure nanobelts were successfully synthesized with controllable light emission properties. By adjusting the oxidation temperature, the nanobelts exhibit white light emission characteristics similar to commercial phosphors. By incorporating these nanobelts into UV-pumped WLED fabrication, a prototype with good luminous efficiency was achieved.