A CuO Nanowire-Based Alternating Current Oxide Powder Electroluminescent Device with High Stability

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Traditional AC powder electroluminescent (EL) devices often suffer from limited operational lifetimes, particularly those based on sulfide phosphors.
• Developing stable and efficient oxide-based phosphors for EL applications remains a challenge.
• Enhancing electric field distribution is crucial for improving EL device performance.

Purpose of the Study:

• To achieve an AC-driven powder electroluminescent (EL) device using a CuO nanowire-Zn2GeO4:Mn phosphor heterogeneous junction.
• To investigate the role of CuO nanowires in enhancing the local electric field for electroluminescence.
• To demonstrate a fabrication method for stable, low-cost, and large-scale EL devices.

Main Methods:

• Synthesis of CuO nanowire arrays via in situ thermal oxidation at 400°C in air.
• Fabrication of heterogeneous structures by drop-coating Zn2GeO4:Mn phosphor suspension onto CuO nanowire arrays.
• Construction and testing of the AC powder EL device, evaluating luminescent performance and brightness maintenance.

Main Results:

• Successful fabrication of an AC-driven powder EL device based on a CuO nanowire-Zn2GeO4:Mn phosphor heterogeneous junction.
• Demonstrated electroluminescence originating from field injection at the CuO nanowire tips, enhancing the oxide phosphor's emission.
• Achieved promising luminescent performance with brightness maintenance over 360 hours, showing less than 1% intensity loss at over 10 cd/m² luminance.

Conclusions:

• The CuO nanowire array effectively enhances the local electric field, enabling electroluminescence in oxide phosphors for EL devices.
• The developed fabrication method is simple, low-cost, and suitable for large-scale production of EL devices.
• This approach offers a potential solution to the limited operational lifetime issues associated with conventional sulfide-based AC powder EL devices.