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

Tandem structures with different subpixels are promising for perovskite‐based multicolor electroluminescence (EL) devices in ultra‐high‐resolution full‐color displays; however, realizing excellent luminance‐ and color‐independent tunability considering the low brightness and stability of blue perovskite light‐emitting diodes (PeLEDs) remains a challenge. Herein, a bright and stable blue gallium nitride (GaN) LED is utilized for vertical integration with a green MAPbBr(3) PeLED, successfully achieving a Pe‐GaN tandem LED with independently tunable luminance and color. The electronic and photonic co‐excitation (EPCE) effect is found to suppress the radiative recombination and current injection of PeLEDs, leading to degraded luminance and current efficiency under direct current modulation. Accordingly, the pulse‐width modulation is introduced to the tandem device with a negligible EPCE effect, and the average hybrid current efficiency is significantly improved by 139.5%, finally achieving a record tunable luminance (average tuning range of 16631 cd m(−2) at an arbitrary color from blue to green) for perovskite‐based multi‐color LEDs. The reported excellent independent tunability can be the starting point for perovskite‐based multicolor EL devices, enabling the combination with matured semiconductor technologies to facilitate their commercialization in advanced display applications with ultra‐high resolution.