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A successful test of Ferroelectric Liquid Crystal Displays (FLCD) on Gen 4.5 is realized in this paper. A new polyimide (PI) that can replace Nylon 6 (N6) is synthesized and tested on the production line. This used to be the barrier in the commercialization of FLCD. Apart from that, a new FLC for mass production is synthesized. To investigate the surface energy and relative performance, various materials are compared. This proof of the feasibility on the production line is a significant step towards the commercialization of field-sequential-color high-resolution FLCDs.

Stimuli-responsive materials have garnered substantial interest in recent years, particularly liquid crystal networks (LCNs) with sophisticatedly designed structures and morphing capabilities. Extensive efforts have been devoted to LCN structural designs spanning from two-dimensional (2D) to three-dimensional (3D) configurations and their intricate morphing behaviors through designed alignment. However, achieving microscale structures and large-area preparation necessitates the development of novel techniques capable of facilely fabricating LCN microstructures with precise control over both overall shape and alignment, enabling a 3D-to-3D shape change. Herein, a simple and cost-effective in-cell soft lithography (ICSL) technique is proposed to create LCN microstructures with customized shapes and predesigned morphing. The ICSL technique involves two sequential steps: fabricating the desired microstructure as the template by using the photopolymerization-induced phase separation (PIPS) method and reproducing the LCN microstructures through templating. Meanwhile, surface anchoring is employed to design and achieve molecular alignment, accommodating different deformation modes. With the proposed ICSL technique, cylindrical and spherical microlens arrays (CMLAs and SMLAs) have been successfully fabricated with stimulus-driven polarization-dependent focusing effects. This technique offers distinct advantages including high customizability, large-area production, and cost-effectiveness, which pave a new avenue for extensive applications in different fields, exemplified by adaptive soft micro-optics and photonics.

Energy-efficient white light-emitting diodes (LEDs) are in high demand across the society. Despite the significant advancements in the modern lighting industry based on solid-state electronics and inorganic phosphor, solid-state lighting (SSL) continues to pursue improved efficiency, saturated color performance, and longer lifetime. Here in this article, robust, narrow emission band nanorods (NRs) are disclosed with tailored wavelengths, aiming to enhance the color rendering index (CRI) and luminous efficacy (LE). The fabricated lighting device consists of NRs of configuration CdSe/ZnxCd1-xS/ZnS, which can independently tune CRI R1-R9 values and maximize the luminous efficacy. For general lighting, NRs with quantum yield (QY) up to 96% and 99% are developed, resulting in ultra-efficient LEDs reaching a record high luminous efficacy of 214 lm W−1 (certified by the National Accreditation Service). Furthermore, NRs are deployed onto mid-power (0.3 W@ 50 mA) LEDs, showing significantly enhanced long-term stability (T95 = 400 h @ 50 mA). With these astonishing properties, the proposed NRs can pave the way for efficient lighting with desired optical spectrum.

In this paper, we present an optically transparent multi-planar 3D display device based on multi-passive matrixed coded pixelated polymer-dispersed liquid crystals (PDLC). The PDLC film used in this experiment has high transparency transmission (97.1%) and fast switching time characteristics within 20ms. We provide a method to display different depth-of-field images by layering them on a multi-layer screen, by which it is possible to render near and far views in different planes, thus bringing 3-dimensional visual information to the observer, ultimately A proof-of-concept prototype of a dual-plane 3D display has been realized. © 2023, John Wiley and Sons Inc. All rights reserved.

Quantum rod (QR) on-chip LED is considered to be a cost-effective application method, but the thermal stability of the material is one of the prime concerns. Thermally induced photooxidation of nanomaterials, in a water-oxygen environment, is the main reason for the attenuation of its luminous intensity. In order to provide an optimized solution and improve device performance, we attempted to analyze the QR composition of CdSe/CdS and CdSe/CdS/ZnS QRs after decay using X-ray photoelectron spectroscopy (XPS) technique and studied the Attenuation mechanisms. © 2023, John Wiley and Sons Inc. All rights reserved.

Applying quantum dot (QDs)-based photoluminescent color filter arrays to mono-color OLED displays and liquid crystal displays is considered a promising method to broaden the color gamut and boost the brightness and efficiency of the display. However, the ambient light could excite the semiconductor QDs and QRs, decreasing the display ambient contrast ratio. Adding a traditional absorptive CF array has limited functions in solving this problem due to the broadband transmission band of pigments. With a larger Stokes shift, QRs are more suitable for suppressing photoluminescent reflection. In this article, we simulate the ambient contrast ratio of a QD/QR-OLED display, considering the parameters of backlight, the Stokes shift, the absorption strength, and spectral properties of QRs, QDs, and absorptive CFs, our discussion provides insight for optimization of the display ambient contrast ratio. © 2023, John Wiley and Sons Inc. All rights reserved.

An approach to developing a thin-film polarizer with high polarization efficiency in liquid crystal cells is presented. The in- cell polarizer facilitates the realization of novel color-conversion liquid crystal displays, where advanced quantum color-converters are used as photoluminescent color filter arrays. We experimentally demonstrated using azo-dye-based embedded polarizers for color-conversion liquid crystal displays for the first time. We systematically designed the device structure and fabrication process. The display is color parallax free and can be driven at regular conditions with good contrast. © 2023, John Wiley and Sons Inc. All rights reserved.

In this article, we proposed a passive vibration sensing system using a threshold-less deformed helix ferroelectric liquid crystal (DHFLC) cell. Combining the DHFLC cell, piezoelectric film, and optical detector, the system can transform the slight vibration into light intensity signal without a power supply. The system can reach the sensitivity of 165 V/(m/s) and the linearity<1% full range output. The proposed system will be combined with optical fibers to play an essential role in various vibration-sensing array applications. © 2023, John Wiley and Sons Inc. All rights reserved.

Down-conversion quantum dot on-chip LED is favored by researchers in the new era due to its excellent optical performance. However, these materials show strong temperature dependence. To solve the thermal stability problem, in this work we studied red CdSe/CdS/ZnS core multi-shell quantum rods (QRs). We found that these specially designed QRs provide a stable photoluminescence properties at relatively higher temperatures. The QRLEDs show 95% of the light intensity at 75 degrees, far exceeding the red-light epitaxial grown LEDs available on the market. Thus, the quantum rods can be a potential candidate for the micro-LEDs and LED products. © 2023, John Wiley and Sons Inc. All rights reserved.

With the continuing prosperity of LiDAR markets, the demand of a fast-scanning, high-precision and inexpensive LiDAR system is growing rapidly. In this paper, we disclose a fast-switchable ferroelectric liquid crystal Dammann grating and polarization grating-based holographic projection and detection system for 3D imaging devices and LiDAR with an extended field of view. The field of view of the proposed system can achieve ~80º with <0.5cm precision at a significantly lower cost. This improvement increases LiDAR versatility and performance in various scenarios. © 2023, John Wiley and Sons Inc. All rights reserved.

The outstanding performance of quantum dots light emitting diodes (QLED), like high color purity, high brightness, high efficiency, and low fabrication cost, has attracted significant attention from academic researchers and industry. A great improvement has been established in QLED performance, but a few works focus on investigating the operation dynamic mechanism that is critical for understanding the device deterioration and further performance improvement. Here, we utilized transient electroluminescence (TREL) to investigate the carrier’s transport dynamics. We believe this method based on TREL will contribute to understanding the carriers’ transport, especially for hole transport and fabricating high-performance QLED devices. Based on the analysis results, we also demonstrated a passive matrix (PM) electroluminescence display panel with high brightness and vivid color. © 2023, John Wiley and Sons Inc. All rights reserved.

The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods (QRs) provide extra benefits among other photoluminescence nanocrystals. Using photo-induced alignment technique, the QRs can be oriented in liquid crystal polymer matrix at a large scale. In this article, a 2D Dammann grating pattern, within “SKL” characters domains aligned QRs in composite film, was fabricated by multi-step photo exposure using several photo masks, and a continuous geometric lens profile pattern aligned QRs was realized by the single step polarization converting holographic irradiation method. Both polarized optical microscope and fluorescence microscope are employed to determine the liquid crystal director profiles and QRs anisotropic excitation properties. We have been able to orient the QRs in fine binary and continuous patterns that confirms the strong quantum rod aligning ability of the proposed method. Thus, the proposed approach paves a way for photo-induced flexible QRs alignments to provide a highly specific and difficult-to-replicate security application at a large scale. © 2023 Chinese Institute of Electronics.

The semiconductor quantum rods (QRs) offer unique benefits that differ from the spherical QDs, such as linearly polarized light and higher light outcoupling efficiency, which can double the external quantum efficiency of the light-emitting diodes (LEDs). Despite having many potential advantages, the QRs are not well explored as QDs in electroluminescent LEDs. In this work, we synthesized CdSe/CdS QRs and verified them in QR-based LEDs. The charge injection into the QRLEDs is precisely controlled to get the maximum charge balance in the device to improve the device's efficiency. We achieved an EQE of 16.8%, which is the highest EQE reported for QRLEDs. The turn-on voltage, peak luminance, and current efficiency (CE) of the QRLEDs are 2.2 V, 10000 cd/m^2, and 11.6%, respectively. The electron injection does not influence the device turn-on voltage but severely impacts the QRLEDs brightness, EQE and CE. The spin coated QRs film has small voids on the surface, which needs to be optimized further to improve the QRLEDs efficiency. Overall, these findings have insightful information on QRLEDs fabrication, which can open up a new opportunity for device applications. © 2023, John Wiley and Sons Inc. All rights reserved.

Quantum dot (QD) light-emitting diodes (QLEDs) have attracted extensive attention due to their high color purity, solution-processability, and high brightness. Due to extensive efforts, the external quantum efficiency (EQE) of QLEDs has approached the theoretical limit. However, because of the efficiency roll-off, the high EQE can only be achieved at relatively low luminance, hindering their application in high-brightness devices such as near-to-eye displays and lighting applications. Here, this article reports an ultralow roll-off QLED that is achieved by simultaneously blocking electron leakage and enhancing the hole injection, thereby shifting the recombination zone back to the emitting QDs layer. These devices maintain EQE over 20.6% up to 1000 mA cm−2 current density, dropping only by ≈5% from the peak EQE of 21.6%, which is the highest value ever reported for the bottom-emitting red QLEDs. Furthermore, the maximum luminance of the optimal device reaches 320 000 cd m−2, 2.7 times higher than the control device (Lmax: 128 000 cd m−2). A passive matrix (PM) QLED display panel with high brightness based on the optimized device structure is also demonstrated. The proposed approach advances the potential of QLEDs to operate efficiently in high-brightness scenarios.

Metasurfaces have ushered in a huge development for their superior ability in manipulating light properties including phase, amplitude, and polarization, which show great potential as alternatives for the refractive optical devices. Recently, many applications of metasurface including metalens have been proposed and investigated, aiming at substituting their refractive counterparts. However, the commonly used fabrication approaches employ electron-beam lithography (EBL) followed by dry etching or atomic layer deposition (ALD) of dielectric materials, which are expensive and inefficient. Besides, dry etching of dielectric materials at sub-100 nm scale with a high aspect ratio is challenging. Herein, a new approach for dielectric metalens fabrication is presented, which combines multilayer nanoimprint lithography and solution phase epitaxy. High aspect ratio ZnO nanopillars with a height-to-diameter ratio of over 7:1 are demonstrated. By using the multilayer nanoimprint lithography, increased aspect ratio nanostructures from shallow imprinting molds are obtained. The highly anisotropic growth characteristic enables nanopillars to grow at a height that exceeds the resist thickness. With this ability, ZnO metalenses are fabricated where the height of nanopillar reaches 1.1 mu m, achieving a focusing efficiency of 50%. The process is cost-effective with a high throughput, which can be widely used for many optical applications.

Single-crystalline metal halide perovskite, due to its large X-ray attenuation coefficient, high carrier mobility, and facile fabrication properties, is considered as a promising candidate material for direct X-ray detectors. Despite the rapid development of high-sensitivity perovskite detectors, their practical application is still hindered by their high dark current levels and the lack of effective approach for assembling the perovskite photodetectors on thin-film transistor (TFT) backplane. Here, it is shown that, by using a supersaturated 2D perovskite precursor as a wet-fusing intermedia, a high-performance 2D/3D perovskite detector can be fabricated and simultaneously attached to the TFT backplane. The assembled 2D/3D heterostructure perovskite detector shows low dark current density, high sensitivity, and low dose detection limit. This work provides a viable route to realize a low-dose, high-resolution direct X-ray image sensor based on perovskite photodetectors. © 2023 Wiley-VCH GmbH.

Triphenylene-based pentaalkynylbenzene dyads and naphthophenanthridine derivativediscotic mesogens have been proven a backbone-like utility for modern optoelectronic applications. Herein, we present the charge transport and organic electronic applications of naphthophenanthridine derivatives and a dimer composed of pentaalkynylbenzene (PA) and triphenylene (TP) discotic liquid crystals (DLCs). Naphthophenanthridine derivatives exhibit a hexagonal columnar (Col(h)) phase; whereas, triphenylene-pentaalkynylbenzene dyads show a columnar centred rectangular (Col(r)) phase and transform into Col(h) phase on doping the pure compounds with an electron-acceptor 2,4,7-trinitrofluorenone (TNF) in a 2:1 TNF/compound ratio. The ambipolar charge transport behaviour of the compounds mentioned above has been investigated by the time-of-flight technique. Naphthophenanthridine derivative renders an ambipolar charge transport, showing temperature-independent electron and hole mobility of the order of 3 x 10(-4) cm(2)/Vs; whereas, TP-PA dimer yields an ambipolar charge carrier mobility of order 10(-3) cm(2)/Vs. The phenazine-fused triphenylene DLC shows unipolar hole mobility of the order of 10(-4) cm(2)/Vs; whereas, hydrogen-bonded Hpz-C-9-TP DLCs exhibit ambipolar charge mobility of the order of 10(-2) cm(2)/Vs. The high ambipolar charge carrier mobility in the investigated DLC compounds makes them suitable for fabricating organic semiconducting electronic devices.