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The extrapolated T50 at 100 cd m−2 for the a-SiNx:H/SiOxNy/hybrid SiOx (ASH)-encapsulated QD-LEDs is estimated to be 9804 h, which is compatible to that of 12112 h for glass lid encapsulated QD-LEDs.

Efficiency roll-off is a significant issue in blue light-emitting diodes (LEDs), but its origin still remains controversial. We report CsPbBr3−xClx/PbBry (or PbCly) (core/shell) quantum dot LEDs exhibiting the emission peak spanning from λpeak = 492 to λpeak = 435 nm by varying the Cl composition (0 ≤ x ≤ 2.21). PLQY and EQE significantly decreased with the increase of the Cl composition. Careful analyses of the composition and the energy structure using EL, PL, TRPL, UPS, XPS and STEM-EDX measurements reveal that the luminance efficiency roll-off in CsPbBr3−xClx LEDs is attributed to the following three combined effects: (1) luminescence quenching by the non-radiative trap-assisted recombination, (2) the hole transfer process at the CsPbBr3−xClx/PbBry core/shell, and (3) imbalanced charge injection caused by a high energy barrier for the hole conduction at the PVK/QD heterointerface (Δh′).

Halide vacancy defect is one of the major origins of non-radiative recombination in the lead halide perovskite light emitting devices (LEDs). Hence the defect passivation is highly demanded for the high-performance perovskite LEDs. Here, we demonstrated that FA doping led to the enrichment of Br in Cs1−xFAxPbBr3 QDs. Due to the defect passivation by the enriched Br, the trap density in Cs1−xFAxPbBr3 significantly decreased after FA doping, and which improved the optical properties of Cs1−xFAxPbBr3 QDs and their QD-LEDs. PLQY of Cs1–xFAxPbBr3 QDs increased from 76.8% (x = 0) to 85.1% (x = 0.04), and Lmax and CEmax of Cs1–xFAxPbBr3 QD-LEDs were improved from Lmax = 2880 cd m−2 and CEmax = 1.98 cd A−1 (x = 0) to Lmax = 5200 cd m−2 and CEmax = 3.87 cd A−1 (x = 0.04). Cs1–xFAxPbBr3 QD-LED device structure was optimized by using PVK as a HTL and ZnO modified with b-PEI as an ETL. The energy band diagram of Cs1–xFAxPbBr3 QD-LEDs deduced by UPS analyses.

Organic electronic devices such as organic light-emitting diodes (OLEDs), quantum dot LEDs, and organic photovoltaics are promising technologies for future electronics. However, achieving long-term stability of organic-based optoelectronic devices has been regarded as a crucial problem to be solved. In this work, a simple and reproducible fabrication method for ultralow water permeation barrier films having a triple-layered (triad) hydrogenated silicon nitride (a-SiNx:H)/nanosilicon oxynitride (n-SiOxNy)/hybrid silicon oxide (h-SiOx) multistructure is presented. Two triad (a-SiNx:H/n-SiOxNy/h-SiOx)n=2 multistructure barrier films are deposited on both sides of a poly(ethylene terephthalate) substrate using a combination of low-pressure plasma-enhanced chemical vapor deposition and dip coating. The deposited films show a high average transmittance (400-700 nm) of 84% and an ultralow water vapor transmission rate of 2 × 10-6 g/m2/day. In the electroluminescence characteristics of OLEDs encapsulated with two triad barrier films, the operational lifetime (T50) of OLEDs is 1584 h, which is almost similar to that (1416 h) of OLEDs encapsulated with a glass lid.

In modern society, advanced technology has facilitated the emergence of multifunctional appliances, particularly, portable electronic devices, which have been growing rapidly. Therefore, flexible thermally conductive materials with the combination of properties like outstanding thermal conductivity, excellent electrical insulation, mechanical flexibility, and strong flame retardancy, which could be used to efficiently dissipate heat generated from electronic components, are the demand of the day. In this study, graphite fluoride, a derivative of graphene, was exfoliated into graphene fluoride sheets (GFS) via the ball-milling process. Then, a suspension of graphene oxide (GO) and GFSs was vacuum-filtrated to obtain a mixed mass, and subsequently, the mixed mass was subjected to reduction under the action hydrogen iodide at low temperature to transform the GO to reduced graphene oxide (rGO). Finally, a highly flexible and thermally conductive 30-μm thick GFS@rGO hybrid film was prepared, which showed an exceptional in-plane thermal conductivity (212 W·m

Owing to the growth of demand for highly integrated electronic devices, high heat dissipation of thermal management materials is essential. Epoxy composites have been prepared with vertically aligned (VA) three-dimensional (3D)-structured SiC sheet scaffolds. The required VA-SiC sheet scaffolds were prepared by a novel approach starting with a graphene oxide (GO) scaffold. The VA-GO scaffolds were reduced to VA-graphene scaffolds in an argon environment, and the latter were subsequently transformed into VA-SiC sheet scaffolds by a template-assisted chemical vapor deposition method. Epoxy resin was filled in the empty spaces of the 3D scaffold of SiC sheets to prepare the composite mass. The material so prepared shows anisotropic thermal property with ultrahigh through-plane conductivity of 14.32 W·m-1·K-1 at a SiC sheet content of 3.71 vol %. A thermal percolation is observed at 1.78 vol % SiC filler. The SiC sheet scaffold of covalently interconnected SiC nanoparticles plays a vital role in the formation of the thermal conductive network to significantly enhance the thermal conductivity of epoxy composites. The application of the VA-SiC/epoxy composite as an efficient thermal dissipating material has also been presented. The VA-SiC/epoxy composites have a strong potential for preparing heat-dissipating components in integrated microelectronics.

Ecofriendly cation metal oxide quantum dots (QDs) are one of the promising candidates to replace for QDs containing expensive indium (In) or hazardous Cd- and Pb-elements. Super-Eg excitation wavel...

With the development of portable and flexible electronic devices, demends for high-performance thermal management materials with high thermal conductivity and electrical insulation are growing. Recently, graphene fluoride has received numerous attention from science community due to its high thermal conductivity and electrical insulation. Here, we report an advanced exfoliated graphene fluoride (EGF) film as a high performance heat spreader and thermal interface material for flexible electronic devices, which simultaneously exhibits ultrahigh thermal conductivity, excellent electrical insulation, and satisfactory flexibility. Commercially available graphite fluoride was directly exfoliated into graphene fluoride solution using ball milling method, followed by preparing ultrathin graphene fluoride films to take full advantage of graphene fluoride properties for heat dissipating applications. The resultant films show a tunable thermal conductivity by altering the thickness of films and show a superior in-plane thermal conductivity of 242 W m−1 K−1 and exceptional through-plane thermal conductivity of 21.8 W m−1 K−1 at the thickness of 10 μm. More interestingly, the graphene fluoride films possess excellent flexibility. The newly developed EGF film provides a creative opportunity for fabrication of multifunctional highly flexible materials, which may promote the development of heat dissipation materials in next generation flexible electronics.

Despite the great interest in inorganic halide perovskites (IHPs) for a variety of photoelectronic applications, environmentally robust nanopatterns of IHPs have hardly been developed mainly owing to the uncontrollable rapid crystallization or temperature and humidity sensitive polymorphs. Herein, we present a facile route for fabricating environment- and phase-stable IHP nanopatterns over large areas. Our method is based on nanoimprinting of a soft and moldable IHP adduct. A small amount of poly(ethylene oxide) was added to an IHP precursor solution to fabricate a spin-coated film that is soft and moldable in an amorphous adduct state. Subsequently, a topographically prepatterned elastomeric mold was used to nanoimprint the film to develop well-defined IHP nanopatterns of CsPbBr3 and CsPbI3 of 200 nm in width over a large area. To ensure environment- and phase-stable black CsPbI3 nanopatterns, a polymer backfilling process was employed on a nanopatterned CsPbI3. The CsPbI3 nanopatterns were overcoated with a thin poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) film, followed by thermal melting of PVDF-TrFE, which formed the air-exposed CsPbI3 nanopatterns laterally confined with PVDF-TrFE. Our polymer backfilled CsPbI3 nanopatterns exhibited excellent environmental stability over one year at ambient conditions and for 10 h at 85 °C, allowing the development of arrays of two-terminal, parallel-type photodetectors with nanopatterned photoactive CsPbI3 channels. Our polymer-assisted nanoimprinting offers a fast, low-pressure/temperature patterning method for high-quality nanopatterns on various substrates over a large area, overcoming conventional costly time-consuming lithographic techniques.

Environmentally friendly metal oxide quantum dot (QD) nanostructures have become attractive alternative materials for replacing QDs containing toxic elements of Cd and Pb. Although many attempts have been proposed for optoelectronic applications of hybrid metal oxide QDs with tailored opto-electronic properties, the fabrication of heterogeneous QD–fullerene hybrids as an emissive material has been studied little for optoelectronic devices. Herein, we report the preparation of ZnO–fullerene C70 (ZnO–C70) QDs by a facile chemical reaction with a zero length linker and demonstrate whitish light-emitting diodes by fullerene induced multicolor emission from the ZnO–C70 QD heterostructure. The electroluminescence (EL) is attributed to three new emission features in the visible region that originate from the electron transitions from three split lowest unoccupied molecular orbital levels of C70 molecules to the valence band of ZnO QDs. Compared with photoluminescence, the EL emission was red-shifted by 50–130 meV due to the interaction between ZnO–C70 QDs in the solid state. The energy levels of C70 were also suitably aligned to those of ZnO QDs with a lower electron transfer barrier of 0.22 eV, which offers an advantageous route for electron transport. Consequently, the environmentally friendly ZnO–C70 QDs with extraordinary properties promise great potential for use as novel encapsulating materials in the field of opto-electronic applications adopting QDs.

A facile thin film encapsulation (TFE) method having a triple-layered structure of a-SiN

Quantum dot light-emitting diodes (QLEDs) are expected to be the basis of next-generation displays and have consequently been extensively investigated with the aim of commercialization. Herein, QLE...

This study demonstrates quantum-dot light-emitting diodes (QD-LEDs) with a function of resistive switching memory, capable of on/off operation at the same driving current depending on reset/set state. The QD-LEDs were fabricated by spin-coating process and experienced two different annealing conditions, which yielded defective or less-defective V2O5–x layer. One of the annealing conditions produced QD-LEDs with the unusual electrical behaviors of negative differential resistance (NDR), capacitance oscillation, and voltage–current hysteresis curves, signifying so-called resistive switching characteristics. X-ray and ultraviolet photoelectron spectroscopies were used to examine the chemical state of the differently annealed V2O5–x layers. The less stoichiometric V2O5–x layer was found to be responsible for the resistive switching behaviors of the NDR and the low and high resistance states (LRS and HRS, respectively). We discuss the LRS/HRS of V2O5–x for resistive switching in terms of a conductive filament effect, induced by microstructural changes caused by oxygen drift and vacancy annihilation processes in the high defect density V2O5–x layer.

In our study, to optimize the electron–hole balance through controlling the electron transport layer (ETL) in the QD-LEDs, four materials (ZnO, ZnGaO, ZnMgO, and ZnGaMgO NPs) were synthesized and applied to the QD-LEDs as ETLs. By doping ZnO NPs with Ga, the electrons easily inject due to the increased Fermi level of ZnO NPs, and as Mg is further doped, the valence band maximum (VBM) of ZnO NPs deepens and blocks the holes more efficiently. Also, at the interface of QD/ETLs, Mg reduces non-radiative recombination by reducing oxygen vacancy defects on the surface of ZnO NPs. As a result, the maximum luminance (Lmax) and maximum luminance efficiency (LEmax) of QD-LEDs based on ZnGaMgO NPs reached 43 440 cd m−2 and 15.4 cd A−1. These results increased by 34%, 10% and 27% for the Lmax and 450%, 88%, and 208% for the LEmax when compared with ZnO, ZnGaO, and ZnMgO NPs as ETLs.

Dielectric elastomer generators (DEGs) are flexible capacitors that convert mechanical into electrical energy. They rely on an external voltage source to charge the capacitor during each operation cycle. An alternative to this is an autonomous DEG which operates with an electret as integrated voltage source. To increase the amount of energy generated per cycle, elastomers with increased permittivity, low viscoelastic losses and high strain at break are of advantage. Here, we report the synthesis of elastic materials with increased permittivity by blending different silicone matrices with nanospring carbon-nanotubes (NS-CNTs) particles and their performance as dielectric in electret DEGs. The best material developed has a dielectric permittivity of e′ = 4.6, a mechanical loss factor of 0.03 and a strain at break of 270%. The output voltage of the DEG constructed using this composite increases from 8.8 V to 14.5 V, when the strain increases from 33% to 66%, respectively. Additionally, the output voltage increases with the rise in permittivity, from 9.3 V for a regular polydimethylsiloxane elastomer (e′ = 2.9) to 14.5 for the best composite (e′ = 4.6).

Zn-doped SnOx/Ag/Zn-doped SnOx(ZTO/Ag/ZTO) multilayer thin films fabricated on a polyethylene terephthalate (PET) substrate using an optimized N2-to-(Ar + O2) gas ratio are used for transparent thin-film heaters with high performance and chemical stability. The ZTO/Ag/ZTO-based multilayer thin film exhibits enhanced durability at high temperatures and humid environments by incorporating nitrogen. The bending test results-there was no significant change in the sheet resistance even after 10,000 bending cycles-highlight the mechanical flexibility of the ZTO/Ag/ZTO multilayer thin film. The ZTO/Ag/ZTO-based thin-film heater on PET, fabricated under optimized deposition gas conditions, exhibits a fast thermal response time of 30 s and a low driving voltage of 6 V to attain 100 °C. It also exhibits uniform heat distribution at saturated temperature and chemical stability after 100 heating-cooling cycles. Hence, the proposed ZTO/Ag/ZTO-based thin-film heater is applicable for use in front and rear window automobile and building applications.

All-solid-state thin-film batteries have been actively investigated as a power source for various microdevices. However, insufficient research has been conducted on thin-film encapsulation, which is an essential element of these batteries as solid electrolytes and Li anodes are vulnerable to moisture in the atmosphere. In this study, a hybrid thin-film encapsulation structure of hybrid SiO

Because of its zero bandgap, graphene has not been considered to be useful for optoelectronic devices that utilize absorption or photoemission phenomena. Even though the finite size 0D graphene quantum dots can open the bandgap due to quantum confinement, graphene composites through hybridization have been investigated to control optical properties. Photoluminescence (PL) quenching or enhancement was achieved by resonance energy transfer to graphene or by the localized surface plasmon of graphene. Reduced graphene oxide (rGO) and graphene oxide (GO) composites with metal oxide (MO) also reduced or increased the PL intensity of the band-edge emission, or visible light emission related to the defect in MO was ascribed to charge transfer from MO to rGO or GO and depended on the amounts of sp2 C–C bonding in rGO and GO. These graphene-based functional composites have been also extensively developed as an active light-emitting material and a very promising candidate for flexible lighting and light-emitting diode.

In this study, Iridium (Ir) metallic layer as an ultra-thin surface modifier (USM) was deposited on ITO coated glass substrate using radio frequency magnetron sputtering for improving the photo-conversion efficiency of organic photovoltaic cells. Ultra-thin Ir acts as a surface modifier replacing the conventional hole transport layer (HTL) PEDOT:PSS in organic photovoltaic (OPV) cells with two different active layers P3HT:PC60BM and PTB7:PC70BM. The Ir USM (1.0 nm) coated on ITO glass substrate showed transmittance of 84.1% and work function of >5.0 eV, which is higher than that of ITO (4.5–4.7 eV). The OPV cells with Ir USM (1.0 nm) exhibits increased power conversion efficiency of 3.70% (for P3HT:PC60BM active layer) and 7.28% (for PTB7:PC70BM active layer) under 100 mW/cm2 illumination (AM 1.5G) which are higher than those of 3.26% and 6.95% for the same OPV cells but with PEDOT:PSS as HTL instead of Ir USM. The results reveal that the chemically stable Ir USM layer could be used as an alternative material for PEDOT:PSS in organic photovoltaic cells.

This work reports about the enhancement of the thermal conductivity of an acrylic pressure-sensitive adhesive (PSA) with the incorporation of functionalized and reduced graphene oxide (frGO...

We present a simple method to improve the thermal and electrical conductivity of epoxy composites via sintering of formic acid-treated Cu nanoparticles (NPs) in the presence of polymethylmethacrylate (PMMA) beads. The surface-treated Cu NPs, epoxy, and PMMA beads were mixed and then sintered under 20 MPa of pressure at 200 °C. The morphology of the Cu NPs and the thermal conductivity, volume resistivity, and thermal stability of the epoxy composites were investigated. The significant improvement of the thermal and electrical conductivity of epoxy composites was attributed to segregation of the Cu NPs between PMMA beads and sintering of neighboring Cu NPs. At 30 wt% of Cu NPs, the thermal conductivity of the epoxy composites was 1.05 W/mK, and the volume resistivity was 5.9 × 1010 Ω cm at a (bead)/(epoxy + bead) ratio of 0.6. The thermal stability of the composites increased with increasing cross-linked PMMA bead content. Low-temperature sintering of formic acid-treated Cu NPs in the presence of PMMA beads affords an innovative way to improve the thermal and electrical conductivity of the composites.

Recently, a theory for cutting supported brushes was published for a blade with an inclined edge. When the angle of inclination is large, the inclined edge may be called a peripheral edge or shear edge, to distinguish the edge from conventional radial edges. However, it is difficult to find a theory for cutting unsupported brushes (most flexible brushes are unsupported brushes). In this study, an inertia force that resists cutting is derived kinetically as a function of time and other conditions. Based on this resisting inertia force, the stresses of the brush are analyzed; the brush is in contact with the edge of the nose with radius re. The outer part of the brush is subject to a high tensile stress owing to the inertia force and bending curvature. The inner part of the brush is subject to a high shear stress due to the inertia force and high contact stress. And also the brush properties determine the conditions that cause fracture of the brush.

We report on InGaZnO (IGZO) thin film transistors (TFTs)-based bio-chemical sensors which can detect the chemical/biological species. As novel sensing platform, the IGZO TFT with Ag nanowire (NW) mesh showed pronounced output voltage changes responding to all analytes of H 2 O 2 , b- d -glucose, d -glucono-1,5-Lactione, and lactic acid, which are reproducible and reversible. Herein, porous Ag NW-functionalized top gate electrode plays a major role in sensing platform for enhanced sensing capability in aqueous medium. Moreover, these top gate geometry serve as a stable backplane for electrical modulation. As a result, analytes solutions become acidic or basic and such pH alterations induce significant turn-on voltage shifts on our devices. For implementation of a resistive load inverter, the output sensing voltage signals can be directly extracted, and such signals are reproducible and reversible. The proposed IGZO TFTs with Ag NW mesh top gate electrode based sensing platform pave the way for development of portable and reusable real-time non-destructive label-free chemical/biological sensors.

Transition metal dichalcogenide (TMD) nanosheets exfoliated in the liquid phase are of significant interest owing to their potential for scalable and flexible photoelectronic applications. Although various dispersants such as surfactants, oligomers, and polymers are used to obtain highly exfoliated TMD nanosheets, most of them are electrically insulating and need to be removed; otherwise, the photoelectric properties of the TMD nanosheets degrade. Here, inorganic halide perovskite nanocrystals (NCs) of CsPbX

Surface engineering of the electron collecting layers (ECLs) is a straightforward and practical strategy to develop high performance inverted structure organic solar cells (OSCs). Here, we systematically investigate four different types of surface modified ECLs to implement high performance low-energy band gap poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-bA]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b ]-thiophenediyl] (PTB7) and [6,6]-phenyl-C70-butyric acid methyl ester (PC 70 BM) based inverted OSCs: (1) single PEIE, (2) ZnO:PEIE mixture (1:1 vol ratio), (3) PEIE/ZnO bilayer, and (4) ZnO/PEIE bilayer. OSCs with the ZnO/PEIE ECL show the highest power conversion efficiency (PCE) value of 8.61% while all the other devices exhibit PCE values of less than 7.80%. The excellent surface coverage as well as proper band alignment of the ZnO/PEIE bilayer leads to the highest device performance.

We report on the effects of zinc oxide (ZnO) morphology on the photovoltaic performance of inverted polymer solar cells (PSCs). Three different ZnO layers, fabricated from a sol–gel, nanoparticles (NPs), or nanorods (NRs), were employed as electron-collecting interlayers (ECIs) to compare their electrical, morphological, and optical properties in poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-bA]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7): [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM)-based inverted PSCs. The work functions of all the ZnO layers were lower than or similar to the electron affinity of the acceptor, PC70BM, allowing the ZnO-coated indium tin oxide (ITO) substrates to act as efficient electron-collecting electrodes. The ZnO NRs induced not only stronger scattering effects but also more efficient electron collection than those of the devices with ZnO sol‒gel or NP ECIs, resulting in enhanced external quantum efficiency and, consequently, the highest power conversion efficiency (8.38±0.09%) under illumination (AM 1.5G, 100 mW/cm2). The optical effects of the ZnO NRs were confirmed by a finite-difference time-domain simulation.

The science and technology of organic electronics have made consistent progress. However, the long-term stability of organic devices is a critical issue that remains to be resolved. Encapsulation is a straightforward and practical means to protect organic materials from oxygen or moisture and thus improve air stability. Here, we report a high-performance flexible inorganic SiNx/SiOxNy hybrid barrier film for application in organic solar cells (OSCs). This hybrid barrier film shows average transmittance of 85.5% and a water-vapor transmission rate of 7.1×10–5 g m−2 day−1. In OSCs comprising poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-bA]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno[3,4-b]-thiophenediyl] (PTB7) and [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM), which were encapsulated by the SiNx/SiOxNy hybrid barrier film, the power-conversion efficiency remained above 86% of the initial value even after 2000 h of storage in air, which is comparable to that obtained for a device encapsulated by a glass lid.

Fabrication of highly flexible, inverted, indium tin oxide (ITO)-free top-emitting quantum-dot light-emitting diodes (QDLEDs) on elastic polyurethane (PU) substrates is reported here. To cope with the irregular surfaces of the PU substrate, polyvinyl alcohol (PVA) is used as a buffer layer. By adopting the PVA buffer layer, we demonstrate red-color and green-color top-emitting QDLEDs that show turn-on voltages from 4.0 V to 4.5 V, and maximum luminance values of 1200 cd m−2 (red) and 4800 cd m−2 (green). In addition, when the QDLEDs are stuck on the curved surfaces (vials and a tumbler), the devices still exhibit a clear light emission. These highly flexible QDLEDs can pave the way for further development of next-generation wearable or attachable displays, or solid-state lighting.

Coaxial type piezoelectric energy generator (C-PEG) nanofiber was fabricated by a self-designed continuous electrospinning deposition system. Piezoelectric PVDF-TrFE nanofiber as an electroactive material was electrospun at a discharge voltage of 9–12 kV onto a simultaneously rotating and transverse moving Cu metal wire at an angular velocity of ω g = 60–120 RPM. The piezoelectric coefficient d33 of the PVDF-TrFE nanofiber was approximately −20 pm V−1. The generated output voltage (V G) increased according to the relationship exp(-α P) (α = 0.41– 0.57) as the pressure (P) increased from 30 to 500 kpa. The V G values for ten and twenty pieces of C-PEG were V G = 3.9 V and 9.5 V at P = 100 kpa, respectively, relatively high output voltages compared to previously reported values. The high V G for the C-PEG stems from the fact that it can generate a fairly high V G due to the increased number of voltage collection points compared to a conventional two-dimensional (2-dim) capacitor type of piezoelectric film or fiber device. C-PEG yarn was also fabricated via the dip-coating of a PDMS polymer solution, followed by winding with Ag-coated nylon fiber as an outer electrode. The current and power density of ten pieces of C-PEG yarn were correspondingly 22 nA cm−2 and 8.6 μW cm−3 at V G = 1.97 V, higher than previously reported values of 5.54 and 6 μW cm−3. The C-PEG yarn, which can generate high voltage compared to the conventional film/nanofiber mat type, is expected to be very useful as a wearable energy generator system.

A simple and industrially scalable ultrasonic spraying was used to prepare an ultrasmooth transparent conductive films (TCFs) of graphene oxide (GO) and single-walled nanotube (SWNT). The hybridization of two-dimensional reduced GO (rGO) and one-dimensional SWNT on polymethylmethacrylate (PMMA) film resulted in flexible TCFs. The vapor treatment of nitric acid on the rGO/SWNT film revealed a significant decrease in sheet resistance. The peeled-off rGO/SWNT/PMMA film from the glass substrate exhibited an exceptionally low surface roughness of 0.54 nm with a light transmittance of 85% and a sheet resistance of 153 Ω/□. The sheet resistance of the TCFs films changed little under 500 bending.

Although various colloidal quantum dot (QD) coating and patterning techniques have been developed to meet the demands in optoelectronic applications over the past years, each of the previously demonstrated methods has one or more limitations and trade-offs in forming multicolor, high-resolution, or large-area patterns of QDs. In this study, we present an alternative QD patterning technique using conventional photolithography combined with charge-assisted layer-by-layer (LbL) assembly to solve the trade-offs of the traditional patterning processes. From our demonstrations, we show repeatable QD patterning process that allows multicolor QD patterns in both large-area and microscale. Also, we show that the QD patterns are robust against additional photolithography processes and that the thickness of the QD patterns can be controlled at each position. To validate that this process can be applied to actual device applications as an active material, we have fabricated inverted, differently colored, active QD light-emitting device (QD-LED) on a pixelated substrate, which achieved maximum electroluminescence intensity of 23 770 cd/m

Two-dimensional (2D) van der Waals (vdW) atomic crystals have been extensively studied and significant progress has been made. The newest 2D vdW material, called black phosphorus (BP), has attracted considerable attention due to its unique physical properties, such as its being a singlecomponent material like graphene, and its having a high mobility and direct band gap. Here, we report on a high-performance BP nanosheet based ferroelectric field effect transistor (FeFET) with a poly(vinylidenefluoride-trifluoroethylene) top-gate insulator for a nonvolatile memory application. The BP FeFETs show the highest linear hole mobility of 563 cm2/Vs and a clear memory window of more than 15 V. For more advanced nonvolatile memory circuit applications, two different types of resistive-load and complementary ferroelectric memory inverters were implemented, which showed distinct memory on/off switching characteristics.