Quantum dots (QDs) offer size-dependent tunability across the infrared to ultraviolet range with narrow emission linewidths and high color purity, making them highly attractive for next-generation light-emitting devices. Quantum dot lightemitting diodes (QLEDs) further combine precise spectral control with scalable, low-cost solution processing, positioning them as strong candidates for wearable, stretchable, and AR/VR display technologies. However, conventional single-emission QLEDs suffer from charge imbalance, efficiency roll-off, and limited operational lifetime, necessitating new device architectures. Tandem QLEDs, which vertically stack multiple emissive layers (EMLs) connected by charge generation layers (CGLs), provide a compelling solution by enabling higher luminance, improved charge balance, and longer lifetime at equivalent current density. The CGL serves as the interfacial region mediating charge injection and generation between adjacent EMLs, directly determining device efficiency and stability. This review highlights recent progress in CGL engineering, categorizing representative designs into planar heterojunction, inorganic-based, and dipole-based configurations. Comparative analysis of their formation mechanisms, material systems, and process compatibilities reveals evolving charge-control strategies that extend beyond material selection. These insights establish design principles for next-generation tandem QLEDs with enhanced efficiency, durability, and manufacturability.

Electrohydrodynamic jet (e-jet) printing, a type of direct contactless microfabrication technology, is a versatile fabrication process that enables a wide range of micro/nanopattern arrays by applying a strong electric field between the nozzle and the substrate. In general, the morphology and the thickness of polymers/quantum dot micropatterns show a systematic dependence on the diameter of the nozzle and the ink composition with a fully automated printing machine. The purpose of this report is to provide typical examples of e-jet printed micropatterns of polymers/quantum dots to explain the effect of each process variable on the result of experiments. Here, we demonstrate several operating conditions that allow high-resolution printing of layers of polymers/quantum dots with a precise control over thickness and submicron lateral resolution.

In this work, we synthesized alloy-core InZnP quantum dots, which are more efficient than single-core InP quantum dots, using a solution process method. The effect of synthesis conditions of alloy core on optical properties was investigated. We also investigated the conditions that make up the gradient shell to minimize defects caused by lattice mismatch between the InZnP core and ZnS is 7.7%. The stable synthesis temperature of the InZnP alloy core was 200℃. Quantum dots consisting of three layered ZnSe gradient shell and single layered ZnS exhibited the best optical property. The properties of quantum dots synthesized in 100 ml and in 2,000 ml flasks were almost equal.

We investigated the temperature-dependent photoluminescence spectroscopy of colloidal InZnP/ZnSe/ZnS (core/ shell/shell) quantum dots with varying ZnSe and ZnS shell thickness in the 278~363 K temperature range. Temperature-dependent photoluminescence of the InZnP-based quantum dot samples reveal red-shifting of the photoluminescence peaks, thermal quenching of photoluminescence, and broadening of bandwidth with increasing temperature. The degree of bandgap shifting and line broadening as a function of temperature is affected little by shell composition and thickness. However, the thermal quenching of the photoluminescence is strongly dependent on the shell components. The irreversible photoluminescence quenching behavior is dominant for thin-shell-deposited InZnP quantum dots, whereas thick-shelled InZnP quantum dots exhibit superior thermal stability of the photoluminescence intensity.

In this study, we report the doping effect of graphene quantum dots (QDs) in nematic liquid crystal (NLC) system on rubbed polyimide (PI) surface. The good LC alignment and high thermal stability in QD-LC cell system on rubbed PI surfaces can be measured. Also, the low threshold voltage of QD-TN cell was observed about 2.77 V. The fast response time of 13.2 ms for QD-TN cell can be achieved. Finally, the good voltage holding ratio of QD-TN cell on rubbed PI surface was measured.

The water soluble quantum dots (QDs) are synthesized by the phase transfer and silica coating reaction. The photoluminescence intensity of silica-coated QDs are mainly affected by the amount of phase transfer agent, SDS (sodium dodecyl sulfate), and the maximum value is obtained at the cmc (critical micell concentration) concentration of SDS in the phase transfer reaction. Based on fluorescence spectra and field emission transmission electron microscope (FETEM), the energy transfer rate by forster resonance energy transfer (FRET) is increasing with the thickness of the silica shell coated on CdSe/ZnS QDs.

The spherical mesoporous silica is synthesized and incorporated with CdSe/ZnS quantum dots(QDs) for preparing micro beads to detect toxic and bio-materials with high sensitivity. The spherical silica beads with the brunauer-emmett-telle(BET) average pore size of 15 nm were prepared with a ratio 1, 3, 5-trimethylbenzen, as a swelling agent, to the block-copolymer template surfactant of over 1 and under vigorous mixing condition. The surface of spherical mesoporous silica is modified using octadecylsilane for incorporating QDs. Based on photoluminescence(PL) spectra, the relative brightness of mesoporous silica beads incorporated with 10 nM of QDs is 79,000 times brighter than that of Rodamine 6 G.