Shaoxin Song,Yang Liu,Xuejuan Liu,Jianping Ge,Dengteng Ge,Lili Yang
Electrically-responsive photonic crystals have drawn extensive interest due to the growing demands of camouflage, displays, sensing, energy-saving buildings, etc., due to their fine control, fast response and convenient implementation. Veiled by the development on hue modulation, brightness/saturation tuning still remains a challenge. This work demonstrates a strategy to modulate the brightness of electrically-responsive photonic pixels via surface charge treatment of electrodes. The reflection intensity is raised by 110% due to the growth of the short-range ordered Fe3O4@C colloidal lattice as a result of enhanced Coulombic forces. The numerical simulation of the potential of the photonic liquid confirms that the potential distribution depends on the electrode surface charge. Furthermore, wide angle-independent photonic colors are well-tuned due to the anisotropic expansion/compression of the photonic lattice via electrophoretic movements of charged particles under an electric field. We believe that our work not only provides a useful way to modulate brightness but also suggests novel designs for electrically-responsive photonic devices.
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.
危险品化学品经营许可证（带存储）