Flexible Displays Research Articles

Coaxial-helix MXene/PANI-based core-spun yarn towards strain-insensitive conductor and supercapacitor

Stretchable electrical conductors hold great promise in the wearable electronic devices, such as flexible display and human-machine interface. Stable conductivity is vital for wearable devices to maintain their stable performance. However, the electrical resistance of most reported yarns dramatically increases when they are deformed. Herein, we propose a design for a coaxial-helix structure by wrapping the polyaniline/MXene-based elastic core-spun yarn on itself in the form of coils. The fabricated coaxial-helix structured yarns (DCSs) exhibit excellent strain-insensitive properties, including low relative resistance change (25.4%), large strain (200%) and high quality factor (17.95). Moreover, the DCSs can be used as the stretchable electrodes for the supercapacitors, and delivers a linear specific capacitance of 256.7 mF cm−1, which is higher than most stretchable yarns. Therefore, the proposed coaxial-helix structure design creates a new approach for the strain-insensitive stretchable conductor, thereby paving the way for the development of stretchy electronics.

GlycoDraw: a python implementation for generating high-quality glycan figures.

Glycans are essential to all scales of biology, with their intricate structures being crucial for their biological functions. The structural complexity of glycans is communicated through simplified and unified visual representations according to the Symbol Nomenclature for Glycans (SNFGs) guidelines adopted by the community. Here, we introduce GlycoDraw, a Python-native implementation for high-throughput generation of high-quality, SNFG-compliant glycan figures with flexible display options. GlycoDraw is released as part of our glycan analysis ecosystem, glycowork, facilitating integration into existing workflows by enabling fully automated annotation of glycan-related figures and thus assisting the analysis of e.g. differential abundance data or glycomics mass spectra.

Preparation and Characterization of Low CTE Poly(ethersulfone) Using Lignin Nano Composites as Flexible Substrates.

Polyethersulfone (PES) has outstanding thermal and dimensional stability. It is considered an engineering thermoplastic. However, its high coefficient of thermal expansion (CTE) hinders its use in automobiles, microelectronics, and flexible display areas. To overcome its high coefficient of thermal expansion (CTE), recent studies have focused on reducing its high CTE and improving its mechanical properties by adding nano-sized fillers or materials. The addition of nanofiller or nanofibrils to the PES matrix often has a positive effect on its mechanical and thermal properties, making it a flexible display substrate. To obtain ideal flexible substrates, we prepared polyethersulfone with lignin nanocomposite films to reduce CTE and improve the mechanical and thermal properties of PES by varying the relative ratio of PES in the lignin nanocomposite. In this study, lignin as a biodegradable nanofiller was found to show high thermal, oxidative, and hydrolytic stability with favorable mechanical properties. PES/lignin nanocomposite films were prepared by solution casting according to the content of lignin (0 to 5 wt.%). PES/lignin composite films were subjected to mechanical, thermo-mechanical, optical, and surface analyses. The results showed enhanced thermomechanical and optical properties of PES, with the potential benefits of lignin filler materials realized for the development of thermoplastic polymer blends.

Luminescence properties of Tb3+/Eu3+ ions activated LiLaSiO4 phosphors for solid-state lighting and flexible display applications

The synthesis and luminescence properties of Tb3+ and Eu3+ single- and co-doped LiLaSiO4 (LLSO) phosphors with energy transfer mechanisms were reported. The rare-earth ions doped LLSO phosphors were synthesized via a solid-state reaction method and their physical characterizations such as phase purity, surface morphology, and elemental analysis were investigated systematically. For the Tb3+ and Eu3+ single- and co-doped LLSO phosphors, their photoluminescence (PL) properties were studied in detail. The LLSO:Tb3+ and LLSO:Eu3+ single-doped phosphors showed superior red and green emissions due to 5D4→7F5 and 5D0→7F2 in the optimized characteristic electronic transitions under ultraviolet (UV) irradiation, respectively. The luminescence performances for both the LLSO:Tb3+ and LLSO:Eu3+ phosphors were optimized at 0.125 mol of doping ion concentration. Under UV excitation, by adjusting the Eu3+ ion concentration in LLSO:0.125Tb3+/Eu3+ phosphors, the tunable emissions from green to red via yellow-orange were obtained. Thus, the tunable emission spectra and luminescence decay lifetimes with increasing the doping content of acceptor ions (Eu3+) confirmed an efficient energy transfer from Tb3+ to Eu3+ ions in the co-doped samples. The critical distance between Tb3+ and Eu3+ was determined to be 13.26 Å and the energy transfer mechanism from Tb3+ to Eu3+ ions was demonstrated to be a dipole-dipole mechanism interaction. In addition, the temperature-dependent PL study was carried out for the LLSO:0.125Tb3+/0.025Eu3+ co-doped phosphor sample and it showed better thermal stability against the temperature quenching. The Tb3+ and Eu3+ single- and co-doped LLSO/polydimethylsiloxane (PDMS) flexible composite films were fabricated by mixing the phosphor powders and PDMS solution. Benefiting from the effective protection of the PDMS matrix, the luminescence stability of the composite films was greatly enhanced. Based on the excellent properties of the synthesized phosphors, Tb3+ and Eu3+ single-doped and Tb3+/Eu3+ co-doped LLSO phosphors could serve as a single-phase multicolor-emitting phosphor under UV excitations.

DGE-CNN: 2D-to-3D holographic display based on a depth gradient extracting module and ZCNN network.

Holography is a crucial technique for the ultimate three-dimensional (3D) display, because it renders all optical cues from the human visual system. However, the shortage of 3D contents strictly restricts the extensive application of holographic 3D displays. In this paper, a 2D-to-3D-display system by deep learning-based monocular depth estimation is proposed. By feeding a single RGB image of a 3D scene into our designed DGE-CNN network, a corresponding display-oriented 3D depth map can be accurately generated for layer-based computer-generated holography. With simple parameter adjustment, our system can adapt the distance range of holographic display according to specific requirements. The high-quality and flexible holographic 3D display can be achieved based on a single RGB image without 3D rendering devices, permitting potential human-display interactive applications such as remote education, navigation, and medical treatment.

Preparation of PP/PC light‐diffusing materials with UV‐shielding property

AbstractIn this study, we presented a one‐step melt‐blending method to fabricate polypropylene (PP)/polycarbonate (PC) light‐diffusing materials. A promising balance between haze and transmittance was obtained by the addition of small amount of PC to the matrix. On the basis of Mie scattering theory and morphology analysis, the correlation between processing conditions and light‐diffusing properties was built. Low rotor speed and high viscosity ratio were beneficial to optical properties of PP/PC composites. To extend the advanced application, two general anti‐ultraviolet additives nanoscale titanium dioxide (Nano‐TiO2) and 2‐(2‐hydroxy‐5‐methylphenyl) benzotriazole (UV‐P) were added to impart UV‐shielding property to the composites. Their specific influences on the morphology and comprehensive properties of PP/PC composites were studied. It was found that the introduction of Rayleigh scattering raised by Nano‐TiO2 could strengthen the scattering effect and cause a significant reduction in light transmittance, while UV‐P had little effect on the optical properties of the light‐diffusing composites. In summary, this study prepared the PP/PC composites with high‐performance light scattering and UV‐shielding properties applying a facile blending method, which showed a potential application in flexible lightings and LCD displays.

Flexible Quantum Dot Light-Emitting Device for Emerging Multifunctional and Smart Applications.

Quantum dot light-emitting diodes (QLEDs), owing to their exceptional performances in device efficiency, color purity/tunability in the visible region, and solution-processing ability on various substrates, become a potential candidate for flexible and ultrathin electroluminescent (EL) lighting and display. Moreover, beyond the lighting and display, flexible QLEDs are enabled with endless possibilities in the era of the internet of things and artificial intelligence by acting as input/output ports in wearable integrated systems. Challenges remain in the development of flexible QLEDs with the goals for high performance, excellent flexibility/even stretchability, and emerging applications. In this paper, we review the recent developments of QLEDs including quantum dot materials, working mechanism, flexible/stretchable strategies, and patterning strategies, and highlight its emerging multifunctional integrations and smart applications covering wearable optical medical devices, pressure-sensing EL devices, and neural smart EL devices. We also summarize the remaining challenges and make an outlook on the future development of flexible QLEDs. The review is expected to offer a systematic understanding and valuable inspiration for flexible QLEDs to simultaneously satisfy optoelectronic and flexible properties for emerging applications. This article is protected by copyright. All rights reserved.

Radioluminescent Cu-Au Metal Nanoclusters: Synthesis and Self-Assembly for Efficient X-ray Scintillation and Imaging.

Zero-dimensional (0D) scintillation materials have drawn tremendous attention due to their inherent advantages in the fabrication of flexible high-energy radiation scintillation screens by solution processes. Although considerable progress has been made in the development of 0D scintillators, such as the current leading lead-halide perovskite nanocrystals and quantum dots, challenges still persist, including potential issues with self-absorption, air stability, and eco-friendliness. Here, we present a strategy to overcome those limitations by synthesis and self-assembly of a new class of scintillators based on metal nanoclusters. We demonstrate the gram-scale synthesis of an atomically precise nanocluster with a Cu-Au alloy core exhibiting high phosphorescence quantum yield, aggregation-induced emission enhancement (AIEE) behavior, and intense radioluminescence. By controlling solvent interactions, the AIEE-active nanoclusters were self-assembled into submicron spherical superparticles in solution, which we exploited as a novel building block for flexible particle-deposited scintillation films with high-resolution X-ray imaging performance. This work reveals metal nanoclusters and their self-assembled superstructures as a promising class of scintillators for practical applications in high-energy radiation detection and imaging.

Implementation of flexible and customizable free-from mirror heads-up display

Implementation of flexible and customizable free-from mirror heads-up display

81‐3: Design of Narrow Border Flexible OLED Display Based on Simulation Analysis and Optimization

This paper analyzes the design of the down border of the flexible OLED display, and studies the influence of the neutral layer and the sensitivity of SD strain of different stacks of Pad Bending in the narrow border area based on the finite element simulation. The neutral layer is located in the PI2 layer, and the order of the strain sensitivity of SD at Bending edge is MCL>Organic layer>PI1>PI2, MCL thickness has the greatest influence on SD strain. Through the stacking optimization design based on the sensitivity analysis results, the SD strain is reduced from 11.1% to 6.6%. Finally realize the industry's smallest R0.1mm Pad Bending design. Based on bending strain gauge and 25N static push test, SD strain is at a safe level and pass more than 50 times push tests. Narrow border products with R0.1mm Pad Bending can pass various environmental reliability tests to meet the environmental requirements of terminal products.

58‐1: Research on 360 Degree Folding AMOLED Display and Optimization Design of Terminal Product By FEA

Aimed at in‐foldable and out‐foldable mobile phone terminal products on the market, a new 360 ° folding terminal scheme which integrates in & out‐foldable is proposed to realize three application modes: in‐fold portable, out‐fold mobile phone and large screen display. According to the application concept of product, the 360 degree hinge and flexible screen have been developed with U‐shaped out‐fold and water‐drop shaped in‐fold. Based on the finite element method, the mechanical simulation model of flexible screen is established, and the modeling method is programmed which is applied to practical engineering test. Based on Lagrange equation and multi‐body system dynamics theory, a system‐level simulation model of rigid‐flexible coupling of 360‐degree folding terminal is established to solve the complex kinematics and dynamic problems, and to achieve the optimal design of each functional module in the mechanism. Combined with the monomer bending test of the flexible screen, the simulation and test results show good consistency. The screen module pass 360 ° bending for 100000 times which verifies the correctness and universality of the scheme of 360 ° folding mechanism.

45‐2: 14.6‐inch 202‐ppi Rollable Micro LED Display with Color Conversion Technology

The 14.6‐inch 202‐ppi rollable micro LED display was fabricated on flexible LTPS TFT backplanes. The tiny micro LEDs, those size are less than 30 um, were bonded on backplanes by flip‐chip soldering technologies. More than 11 million micro LEDs were transferred to achieve brightness of >1000 nits, contrast ratio of >1,000,000:1 and resolution of 2560xRGBx1440. We investigated the structure and mechanism to achieve the rollable capability for micro LED displays.

88‐3: Late‐News Paper: IGZO Backplane for Full‐color Electrophoretic Display

E Ink's Gallery™ 3 with SDTC's IGZO backplane are being developed to have short page update time and good color image quality for full‐color EPD. Since the backplane for Gallery™ 3 must be driven by high voltage approximately close to +/‐ 30V, stable TFT characteristics and low TFT off‐leakage under high voltage application are important. SDTC's IGZO TFT was confirmed to be superior in terms of stability against high voltage application. An 8‐inch 300dpi Gallery™ 3, which is now in mass production, achieves page update time of less than 1 second in full color mode and 0.35 seconds in monochrome mode. Beyond the IGZO TFT employed in the 8‐ inch Gallery™ 3 panel, we have also proved the IGZO TFT with further high mobility, whose mobility is 3‐times higher than that of the current 8” panel, developed at SDTC has excellent characteristics stability against high voltage application as well, and it is currently being developed for mass production of EPD. We are also developing flexible IGZO EPD and large screen size IGZO signage EPD as the future technologies.

P‐144: Late‐News Poster: Evaluation for Flexible Substrates According to the Number of Rollings

A scratch test was performed to evaluate the substrate deformation according to the number of rolling times for the rollable display. For polyimide and thermal plastics polyurethane, the critical loads are analyzed according to the number of rolling times. As increasing the load, friction coefficients were measured during the scratch on films. The effect of substrate rolling times on plastic n and elastic deformations were evaluated.

72‐1: Invited Paper: Improving Improving Thermal Stability of The Coatable Polarizer by Optimization of Materials

In this paper, we fabricated the coatable polarizer based on guest‐host effect between the host polymerizable liquid crystal and the guest dichroic dye. However, its thermal stability is poor. We had attempts to optimize the structure of its materials and we obtained the optimized polarizer. It had a very small color difference of 2.91, and its DOP was only reduced from 99.0% to 96.2% with a samll loss of 2.7% after being heated at 90°C for 120 hours. It shows that the thermal stability is greatly enhanced. It will benefit the coatable polarizer's development of applications in ultra‐thin, ultra‐wide size and flexible display fields.

74‐1: Invited Paper: Highly Stretchable and Shrinkable AMOLED for Free Deformation

Flexible display technology has been successfully commercialized with foldable and rollable displays. Because of the limitation of the flexible technology, stretchable displays have attracted great attention which capable of realizing freeform design as a post‐flexible display. However, no technology has yet provided sufficient stretchability and resolution to realize genuine free‐form displays. We report on a highly deformable AMOLED display which capable of elongation over 20%. Moreover, our display is capable of more than 15% shrinkage deformation. We also developed low‐temperature thermal shrink process to make the most of the potential of the display. The fabricated full‐color stretchable AMOLED shows excellent deformability with high pixel density.

43‐2: Distinguished Student Paper: High‐Performance, Coplanar Amorphous IGZO TFTs by Spray Pyrolysis on PI Substrate for Low Cost Manufacturing of Foldable AMOLED Display

We report a method for low‐cost deposition of bubble‐free and high‐quality amorphous InGaZnO (a‐IGZO) on polyimide (PI) substrate for foldable AMOLED display by spray pyrolysis. The coplanar thin‐film transistor (TFT) with spray‐pyrolyzed (SP) a‐IGZO on PI substrate exhibits VTH of ‐0.8 V, μSAT of 40.95 cm2V‐1s‐1, and SS of 0.18 Vdec‐1 with on/off current ratio of ~108. The TFT shows VTH shift of ‐0.40 V and +0.05 V under tesnsile bending and positive bias temperature stress, respectively. The ring oscillator made of SP a‐IGZO TFTs exhibits an oscillation frequency of 2.38 MHz at VDD of 10 V. The SP a‐IGZO TFT can be used for low‐cost, high‐performance, and flexible display TFT backplanes.

Template‐Assisted Fabrication of Flexible Perovskite Scintillators for X‐Ray Detection and Imaging

AbstractMetal halide perovskites have recently emerged as exceptional scintillator materials for ionizing radiation detection devices. Their chemical composition consists of elements with high atomic numbers, leading them to have a high attenuation coefficient. Their high attenuation coefficient, in combination with their excellent optoelectronic properties, versatile chemical tunability, and facile and low‐cost fabrication processes, makes them the ideal scintillator material. However, existing perovskite‐based scintillators suffer from poor material stability, especially in humid atmospheres. Moreover, current perovskite films have morphologies that have been optimized for photovoltaics, which results in the relatively long charge carrier lifetimes, a property that is detrimental for fast scintillation. Furthermore, existing reports of perovskite‐based scintillators have shown limited spatial resolution due to poor light transmittance that arises from light scattering from large aggregates of perovskite grains. To address these issues, this work introduces a template‐assisted in situ polymerization‐based process to prepare perovskite/polymer composite scintillators that simultaneously reduces afterglow effects, improves perovskite stability, and is industrially scalable. The optimized perovskite scintillators are then incorporated into X‐ray detection devices to investigate detection performance and device stability. Compared with existing commercial scintillators, the perovskite scintillators show superior detection performance metrics for imaging, indicating the great potential of perovskites for next‐generation, large‐area, and flexible scintillation screens.

2D Perovskite Mn2+ -Doped Cs2 CdBr2 Cl2 Scintillator for Low-Dose High-Resolution X-ray Imaging.

High-performance X-ray scintillators with low detection limits and high light yield are of great importance and are a challenge for low-dose X-ray imaging in medical diagnosis and industrial detection. In this work, the synthesis of a new 2D perovskite, Cs2 CdBr2 Cl2 , via hydrothermal reaction is reported. By doping Mn2+ into the perovskite, a yellow emission located at 593nm is obtained, and the photoluminescence quantum yield (PLQY) of Cs2 CdBr2 Cl2 :5%Mn2+ perovskite reaches the highest value of 98.52%. The near-unity PLQY and negligible self-absorption of Cs2 CdBr2 Cl2 :5%Mn2+ enable excellent X-ray scintillation performance with a high light yield of 64 950 photons MeV-1 and low detection limit of 17.82 nGyair s-1 . Moreover, combining Cs2 CdBr2 Cl2 :5%Mn2+ with poly(dimethylsiloxane) to fabricate a flexible scintillator screen achieves low-dose X-ray imaging with a high resolution of 12.3 line pairs (lp) mm-1 . The results suggest that Cs2 CdBr2 Cl2 :5%Mn2+ is a promising candidate for low-dose and high-resolution X-ray imaging. The study presents a new approach to designing high-performance scintillators through metal-ion doping.

Theoretical insight on the charge transport properties: The formation of "head-to-tail" and "head-to-head" stacking of asymmetric aryl anthracene derivatives.

Organic semiconductors (OSCs) are widely used in flexible display, renewable energy, and biosensors, owing to their unique solid-state physical and optoelectronic properties. Among the abundant crystal library of OSCs, asymmetric aryl anthracene derivatives have irreplaceable advantages due to the interplay between their distinct π-conjugated geometry and molecular stacking as well as efficient light emission and charge transport properties that can be simultaneously utilized. However, the poor crystal stacking patterns of most asymmetric molecules limit their utility as excellent OSCs. Thus, it is crucial to clarify the structural features that enable the extremely ordered stacking and favorable electronic structure of asymmetric anthracene derivatives to become high-performance OSCs. This contribution investigates the charge transport properties of a series of asymmetric aryl anthracene derivatives to reveal the modulation factors of the molecular stacking modes and to explore the structural factors, which are beneficial to charge transport. The analysis demonstrated that the vinyl-linker facilitated the injection of hole carriers, and the alkynyl-linker effectively reduces the reorganization energy. Importantly, the linear polarizability and permanent dipole moment of a single molecule play a vital regulation to molecular stacking modes and the transfer integral of the dimer. The "head-to-head stacking" motif shows a compact stacking pattern and the maximum 2D anisotropic mobility more than 10cm2V-1s-1. These findings sharpen our understanding of the charge transport properties in asymmetric organic semiconductors and are essential for developing a diverse range of high-performance OSC materials.