Perovskite-Gallium Nitride Tandem Light-Emitting Diodes with Improved Luminance and Color Tunability

Area of Science:

• Materials Science
• Optoelectronics
• Display Technology

Background:

• Perovskite-based multicolor electroluminescence (EL) devices are promising for ultra-high-resolution displays.
• Challenges include low brightness and stability of blue perovskite light-emitting diodes (PeLEDs), hindering independent luminance and color tuning.
• Existing tandem structures face limitations due to the electronic and photonic co-excitation (EPCE) effect impacting PeLED performance.

Purpose of the Study:

• To achieve independently tunable luminance and color in perovskite-based multicolor LEDs.
• To overcome the limitations of blue PeLEDs in tandem structures for advanced display applications.
• To improve the performance and commercial viability of perovskite-based EL devices.

Main Methods:

• Vertical integration of a blue gallium nitride (GaN) LED with a green MAPbBr3 PeLED to create a Pe-GaN tandem LED.
• Investigated the electronic and photonic co-excitation (EPCE) effect on PeLED performance under direct current modulation.
• Implemented pulse-width modulation (PWM) to mitigate the EPCE effect and enhance device efficiency.

Main Results:

• Successfully fabricated a Pe-GaN tandem LED with independently tunable luminance and color.
• Identified EPCE effect as a cause for luminance degradation under direct current modulation.
• Achieved a 139.5% improvement in average hybrid current efficiency using PWM, reaching a record tunable luminance of 16631 cd m⁻².

Conclusions:

• The developed Pe-GaN tandem LED demonstrates excellent independent tunability for luminance and color.
• Pulse-width modulation effectively suppresses the EPCE effect, significantly boosting device performance.
• This work provides a foundation for commercializing perovskite-based multicolor EL devices in ultra-high-resolution displays.