RESUMEN
Indium gallium nitride (InGaN)-based micro-LEDs (µLEDs) are suitable for meeting ever-increasing demands for high-performance displays owing to their high efficiency, brightness and stability1-5. However, µLEDs have a large problem in that the external quantum efficiency (EQE) decreases with the size reduction6-9. Here we demonstrate a blue InGaN/GaN multiple quantum well (MQW) nanorod-LED (nLED) with high EQE. To overcome the size-dependent EQE reduction problem8,9, we studied the interaction between the GaN surface and the sidewall passivation layer through various analyses. Minimizing the point defects created during the passivation process is crucial to manufacturing high-performance nLEDs. Notably, the sol-gel method is advantageous for the passivation because SiO2 nanoparticles are adsorbed on the GaN surface, thereby minimizing its atomic interactions. The fabricated nLEDs showed an EQE of 20.2 ± 0.6%, the highest EQE value ever reported for the LED in the nanoscale. This work opens the way for manufacturing self-emissive nLED displays that can become an enabling technology for next-generation displays.
RESUMEN
This work reports the synthesis and application of highly tuned cadmium-free green and red InPZnSe1-xSx/ZnS quantum dots (QDs) in QD enhanced liquid crystal displays (LCD). The emissions of the quantum dots were synthetically tuned to sharp emissions at low full-width at half maximum. The QDs were incorporated in LCD devices as quantum dot enhancement film (QDEF) or as a quantum dot incorporated color filter (QDCF). Synthetic tuning of the gradient inter-shell in the QDs leads to reduced full width at half-maximum, resulting in sharp green and red emissions from both types of devices. The application of the same QDs to devices using these different integration techniques shows the superiority of QDCF devices over QDEF ones. The RGB color gamut of a QDCF-LCD was 81.4% of REC.2020 in the CIE 1931 color space compared to 71.2% obtained for a QDEF-LCD display. The improved performance of QDCF was mainly due to the optimal interactions between the green QDs and the green color filter. The superior performance of cadmium-free InPZnSe1-xSx/ZnS QDCFs in LCDs make them well-suited for ultra-high-definition TV formats.
RESUMEN
Quantum dot enhancement film (QDEF) working in tandem with a blue light-emitting-diode (LED) back-light-unit (BLU) has been recently used in liquid crystal display (LCD) to minimize the cross talks between the polarized emitting B-, G-, and R-light. However, they still exhibit a fundamental and considerable emitting-light-power loss from QDEF because of the light absorption loss in resin and transparent films of QDEF. In this work, we propose and demonstrate the superiority of the LCD using blue-(B-), green-(G-), and red-(R-) perovskite-quantum-dot (PrQD) functional CFs coupled with a blue LED BLU. This LCD using PrQD functional CFs and a blue LED BLU features cross-talk free spectra of polarized emitting B-, G-, and R-light, maximizing the LCD color gamut and exhibiting a world record performance of over 102.7% (137%) of Rec.2020 standard (NTSC standard). Theoretically, such an improvement in color gamut would facilitate unlimited scaling-down of the pixel leading to super ultra-high resolution LCD.