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In this article, a photoalignment layer, based on the azo dye and liquid crystal polymer (LCP) composite is proposed. The alignment layer offers easy processing and high photo and thermal stabilities. The high VHR (99.1%) and low RDC (30mV) have been achieved that is comparable with the conventional PI rubbing alignment layer. The proposed alignment layer shows low pre-tilt angle and small image sticking which is highly desirable for IPS display. Furthermore, the ability of multi-domain alignment has been demonstrated that shows a great potential to find applications in a range of electro-optical devices particularly those requiring in-plane LC director modulations. [ABSTRACT FROM AUTHOR]

As amorphous oxide semiconductors (AOSs) are hotly pursued for advanced displays, flexible electronics, optoelectronics, and neuromorphic systems, the AOS Schottky barrier diodes (SBDs) have been tried only using the mainstream amorphous InGaZnO (a‐IGZO) and the conservative bottom‐anode structure. To deepen the study on AOS SBDs, the more challenging top‐anode SBD is developed in this work using a versatile but vulnerable AOS, amorphous InZnO (a‐IZO). Unsurprisingly, the Schottky interface defects are seriously increased by the top‐anode process and the defective a‐IZO, which cannot be effectively passivated using the incumbent oxidizing treatments. The hydrogenation is proposed to considerably suppress these annoying interface defects and thus correspondingly reduces the large leakage current, while the hydrogen doping easily deteriorates a‐IGZO SBD. The underlying mechanism of such distinction is revealed to be the tricky interactions between defect and hydrogen in AOSs. Based on the sophisticated utilization of such defect‐hydrogen interplay, the a‐IZO/a‐IGZO stack is hydrogenated together to simultaneously realize a high‐conductivity bulk and low‐defect interface, noticeably enhancing the performance metrics. Such top‐anode SBD based on hydrogenated multilayer AOSs successfully blazes a novel evolution path for AOS SBDs. [ABSTRACT FROM AUTHOR]

Azo dyes are valuable functional materials due to their sensitive response to and effective modulation of polarized light. It is essential to find out not only the optical anisotropy but also the complex refractive index of azo dye materials for photonics applications. We report here such measurements of highly ordered photoaligned azo dye films. The film has an apparent dichroic ratio of about 60. We model the photoaligned azo dye film systems using the Berreman transfer matrix. By means of regression fitting of the polarization dependent transmittance and reflectance data, we were able to determine the complex refractive indices of the aligned film at the wavelength range of 400–1000 nm. This material is found to have exceptionally large optical birefringence (Δn ∼ 0.75 at 632.5 nm and Δn ∼ 0.48 at 850.6 nm). The aligned azo dye film is valuable to applications such as coatable polarizers and optical modulation devices. [ABSTRACT FROM AUTHOR]

Stable ferroelectric liquid crystal (FLC) elements have been realised by optically stabilised alignment film and thermally stabilised alignment film. The two methods of fabricated FLC elements have been explored for different aspects, namely alignment quality, electro-optical response and their possibility for complicate aligning patterns such as grating and Pancharatnam–Berry lens. They are compared based on different requirements of applications. With these two approaches, we are able to produce various types of FLC photonic and display devices with good photostability. [ABSTRACT FROM AUTHOR]

There are a series of polyimide material synthesized and studied with different dianhydride and diamine structures. By exploring the structural variations of these materials and their surface energy characteristics, we successfully obtained ferroelectric liquid crystal devices exhibiting exceptional optical and electrical properties. Notably, our findings highlight that a specific polyimide material comprised of dianhydride with a benzene ring structure and diamine with a long-chain amino structure demonstrates remarkable achievements, including a maximum contrast of 872 and a rapid response speed of less than 0.1 ms. These results establish the superiority of this particular polyimide material over its commercially available counterparts. Additionally, the optical characteristics of various polyimide materials were examined by establishing a correlation between these properties and the surface energy of the materials. This research presents a novel approach to developing alignment materials suitable for ferroelectric liquid crystal applications. The implications of our findings are of great significance in driving advancements in field-sequential-color display devices with high pixels per inch in the ferroelectric liquid crystal field. The FLC cells containing optimized polyimide (PI) composed of dianhydride and diamine structural components exhibit outstanding optical contrast and response speed. [Display omitted] • Polyimide (PI) materials with different dianhydride and diamine structures have been synthesized and studied. • FLC devices based on optimized PI display excellent contrast ratio of 872 and a rapid response speed of less than 0.1 ms. • The optimized PI material has been successfully implemented in the LCD Generation 4.5 mass production line. [ABSTRACT FROM AUTHOR]

Pancharatnam-Berry phase optical elements (PBOEs) have received much attention due to their ability to generate complex structured light or to manipulate the shape of a light beam. This work demonstrates a tunable liquid crystal (LC) Pancharatnam-Berry (LCPB) lens using a simple and cost-effective PB phase hologram optical setup and thermal polymerization to form an irreversible photo-patterning alignment layer. The LCPB lens with high photo-stability supports ultra-broadband operation and provides a diffraction efficiency of ∼90 % throughout the visible spectral range, achieved by applying the appropriate voltages. The LCPB lens functions as a convex or a concave lens, depending on the handedness of the circularly polarized incident light, so its image reduction and magnification functions are demonstrated, and its photo-stability is characterized. The fabrication of the proposed LC PBOEs is simpler and more cost-effective than previous methods, and the irreversible photo-patterning alignment layer that is formed by thermal polymerization allows larger operational bandwidths, supporting new applications.

Self-powered smart windows are desirable with the expectations of their energy-saving, weather-independent, user-controllable, and miniature performance. Recently developed solar- or thermal-powered smart windows largely depend on the weather conditions and have an extremely slow response, and only a certain portion of the saved energy can be utilized by the external circuit for mode conversion. In this work, a self-powered normally transparent smart window was developed by the conjunction of a rotary freestanding sliding triboelectric nanogenerator (RFS-TENG) and a polymer network liquid crystal (PNLC) cell. To fabricate the PNLC cell, the alignment layer with randomly distributed microdomains was constructed to encapsulate a mixture of LC polymers and nematic LCs. The opacity of the smart window exposed to an alternating electric field was considerably improved owing to the embedded microdomains and a dense web of LC polymers. The ultrahigh haziness greatly alleviates the charge density required for the LC actuation and thus enables the driving by the TENG where the charge amount is usually limited. The RFS-TENG was elaborately designed with six periodic bent triboelectric films and Ag electrodes, which presented an ultralow friction wear and met the frequency requirement to achieve the steady opacity. By harvesting the mechanical energies from ambient environments, the tribo-induced smart window can benefit a wide variety of fields, such as self-powered sunroofs, wind-driven smart farming systems etc .

Bistable electrical switching of high-efficiency grating diffractions is realized by adding a front π-bistable twisted nematic (π-BTN) cell to a passive liquid crystal polarization grating (LCPG). The π-BTN cell can be switched between stable non- and 180°-twisted states, acting as a polarization converter that switches the polarization of a laser beam and thus changes the diffraction behavior of the LCPG. Both states of the π-BTN cell are stable and can be reversibly switched to each other by applying a voltage pulse of different frequencies. We experimentally demonstrate two bistable-switching operations: (i) the BTN-LCPG can either split or deflect the laser beam; and (ii) the BTN-LCPG can selectively diffract the laser beam to the +1st and -1st orders, while maintaining a high diffraction efficiency of ∼90%. With electrical switchability, a simple optical design, and low power consumption, the proposed BTN-LCPG concept is favorable in various applications.