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Quantum dot light-emitting diodes (QLEDs) hold great promise for next-generation display applications owing to their exceptional optical properties and versatile tunability. In this study, we investigate the effects of quantum dot (QD) shell thickness, polyethylenimine (PEI) concentration, and PEI layer position on the performance of inverted QLED devices. Two types of alloyed-core/shell QDs with varying shell thicknesses were synthesized using a one-pot method with mean particle sizes of 8.0 ± 0.9 nm and 10.3 ± 1.3 nm for thin- and thick-shelled QDs, respectively. Thick-shelled QDs exhibited a higher photoluminescence quantum yield (PLQY) and a narrower emission linewidth compared to their thin-shelled counterparts. Next, QLEDs employing these QDs were fabricated. The incorporation of PEI layers on either side of the QD emissive layer significantly enhanced device performance. Using PEI on the hole transport side resulted in greater improvement than on the electron injection side. Sandwiching the QD layer between two PEI layers led to the best performance, with a maximum external quantum efficiency (EQE) of 17% and a peak luminance of 91,174 cd/m2 achieved using an optimized PEI concentration of 0.025 wt% on both electron injection and hole injection sides. This study highlights the critical role of QD shell engineering and interfacial modification in achieving high-performance QLEDs for display applications.

Microdisplay technologies include a variety of miniature display solutions designed to specific requirements in various applications, such as near-to-eye (NTE) platforms. Among these solutions, OLED based microdisplays stands out as an advanced micro-display technology that goes beyond the core principles of conventional OLED technology. This review investigates deeply into the landscape of OLED-on-Silicon (OLEDoS) microdisplays, providing a meticulous analysis of both the CMOS backplane and the OLED frontplane technology, along with subsidiary technologies. It thoroughly examines the challenges and potential drawbacks associated with each technology, offering a comprehensive understanding of their limitations. It also sheds light on the advancements and breakthroughs in the field and highlights the design considerations to overcome the outlined limitations. OLEDs are ideal for microdisplays due to their high contrast ratios, deep blacks, and fast response times, all essential for eXtended Reality (XR) experiences. Their self-emissive nature, which eliminates the need for backlighting, enabling thin, light, power-efficient displays with vibrant colors. These features make OLEDoS microdisplays particularly well-suited for NTE platforms. The review also examines the commercial landscape of OLEDoS, covering market trends, major industry players, and the adoption of these technologies across the industry. In conclusion, it provides a forward-looking perspective on the future of OLEDoS microdisplays, outlining emerging trends and opportunities within the rapidly evolving XR ecosystem.

Organic Light Emitting Diode (OLED) technology is preferred in modern display applications due to its superior efficiency, color quality, and flexibility. It also carries a high potential of applicability in military displays where emission color tuning is required for MIL-STD-3009 Night Vision Imaging Systems (NVISs), as compatibility is critical. Herein, we report the effects of different OLED device layer materials and thicknesses such as the hole injection layer (HIL), hole transport layer (HTL), and electron transport layer (ETL) on the color coordinates, luminance, and efficiency of OLED devices designed for night vision (NVIS) compatibility. In this study, simulation tools like SETFOS® (Semi-conducting Emissive Thin Film Optics Simulator), MATLAB®, and LightTools® (Illumination Design Software) were used to verify and validate the luminance, luminance efficiency, and chromaticity coordinates of the proposed NVIS-OLED devices. We modeled the OLED device using SETFOS®, then the selection of materials for each layer for an optimal electron–hole balance was performed in the same tool. The effective reflectivity of multiple OLED layers was determined in MATLAB® in addition to an optimal device efficiency calculation in SETFOS®. The optical validation of output luminance and luminous efficiency was performed in LightTools®. Through a series of simulations for a green-emitting OLED device, we observed significant shifts in color coordinates, particularly towards the yellow spectrum, when the ETL materials and their thicknesses varied between 1 nm and 200 nm, whereas a change in the thickness of the HIL and HTL materials had a negligible impact on the color coordinates. While the critical role of ETL in color tuning and the emission characteristics of OLEDs is highlighted, our results also suggested a degree of flexibility in material selection for the HIL and HTL, as they minimally affected the color coordinates of emission. We validated via a combination of SETFOS®, MATLAB®, and LightTools® that when the ETL (3TPYMB) material thickness is optimized to 51 nm, the cathode reflectivity via the ETL-EIL stack became the minimum enabling output luminance of 3470 cd/m2 through our emissive layer within the Glass/ITO/MoO3/TAPC/(CBP:Ir(ppy)3)/3TPYMB/LiF/Aluminum OLED stack architecture, also yielding 34.73 cd/A of current efficiency under 10 mA/cm2 of current density. We infer that when stack layer thicknesses are optimized with respect to their reflectivity properties, better performances are achieved.

Since its invention in the 1960s, one of the most significant evolutions of metal-oxide semiconductor field effect transistors (MOSFETs) would be the 3D version that makes the semiconducting channel vertically wrapped by conformal gate electrodes, also recognized as FinFET. During recent decades, the width of fin (Wfin) and the neighboring gate oxide width (tox) in FinFETs has shrunk from about 150 nm to a few nanometers. However, both widths seem to have been leveling off in recent years, owing to the limitation of lithography precision. Here, we show that by adapting the Penn model and Maxwell–Garnett mixing formula for a dielectric constant (κ) calculation for nanolaminate structures, FinFETs with two- and three-stage κ-graded stacked combinations of gate dielectrics with SiO2, Si3N4, Al2O3, HfO2, La2O3, and TiO2 perform better against the same structures with their single-layer dielectrics counterparts. Based on this, FinFETs simulated with κ-graded gate oxides achieved an off-state drain current (IOFF) reduced down to 6.45 × 10−15 A for the Al2O3: TiO2 combination and a gate leakage current (IG) reaching down to 2.04 × 10−11 A for the Al2O3: HfO2: La2O3 combination. While our findings push the individual dielectric laminates to the sub 1 nm limit, the effects of dielectric permittivity matching and κ-grading for gate oxides remain to have the potential to shed light on the next generation of nanoelectronics for higher integration and lower power consumption opportunities.