Cholesteric liquid crystal polymer network (CLCN) mirrors featuring a broad reflection band have attracted considerable interest for use in optical filters and decorative applications. To date, however, the development of mirrors with encryption capabilities remains unexplored. In this work, a series of chiral additives were synthesized from isosorbide and 4'-n-alkyl-(1,1'-biphenyl)-4-carboxylic acids. Using polymerization-induced chiral additive diffusion, we then prepared a set of CLCN films exhibiting broad reflection bands. By stacking these films with an optically clear adhesive, a broadband CLCN mirror with high reflectance was fabricated. Furthermore, a patterned half-wave plate was fabricated using a nematic liquid crystal polymer network (NLCN) in combination with a CLCN. A modified mirror was constructed by incorporating the patterned half-wave plate during the stacking process. When illuminated with circularly polarized light, this configuration revealed vivid colored images. These results demonstrate the potential of such mirrors for encryption purposes.

Abstract In recent years, research on metal–halide perovskites have expanded rapidly, positioning these materials as highly promising semiconductors thanks to their remarkable optoelectronic properties. When chiral molecules are introduced into the crystal lattice, or when chiral ligands are attached to the surface, it becomes possible to obtain chiral metal–halide perovskites. These materials combine the excellent electronic and optical characteristics of conventional perovskites with intrinsic chirality, which gives rise to unique functionalities such as circular dichroism (CD), circularly polarized luminescence (CPL), nonlinear optical responses, spintronic behavior, ferroelectricity, and the chiral-induced spin selectivity (CISS) effect. As a result, these materials hold great promise for applications in optoelectronics, optical devices, photovoltaics, and spintronics. This review summarizes recent developments in chiral metal–halide perovskites, focusing on their synthesis strategies, crystal structures, mechanisms behind chirality induction, CPL behavior, and emerging applications. Building on these advances, the key challenges that currently limit their progress are discussed, together with possible directions for future research. A deeper understanding of the optoelectronic properties and design principles of chiral metal–halide perovskites is expected to provide valuable theoretical guidance and support the development of next-generation chiral perovskite materials.

Lead-free double perovskites (DPs) are emerging as sustainable luminescent materials owing to their low-cost synthesis, low toxicity, and superior stability. However, their practical applications are impeded by low luminescence efficiency and a single emission center. To overcome these challenges, we reported a structure-modulation strategy to develop Sb/Er: Cs2Na0.95Ag0.05YbCl6 (Sb/Er: CNAYC) DPs by co-doping Cs2NaYbCl6 with Sb3+/Er3+ ions and substituting Na+ with Ag + ions. The Sb3+/Er3+ co-doping can introduce multiple emission centers from visible to near-infrared (NIR). Meanwhile, the Na+-Ag+ alloying-induced lattice distortion not only enhances the photoluminescence efficiency by breaking the parity-forbidden transitions, but also enables the color of emission to be tuned to the white light range. The Sb/Er: CNAYC DPs simultaneously deliver efficient blue (460 nm@Sb3+), green/red (552/667 nm@ Er3+) and NIR (980/1540 nm@Yb3+/Er3+) emissions, providing a promising luminescent material for single-component white/NIR LEDs. Furthermore, the Sb/Er: CNAYC DPs also display pronounced temperature-sensitive fluorescence intensity ratio (FIR) and lifetime characteristics, enabling them well-suited for dual-mode temperature sensing. This study is expected to establish a universal lattice-modulation strategy that yields single-component luminescent materials exhibiting both high-efficiency white/NIR emission and accurate multimode thermometry for next-generation optoelectronic applications.

Multifunctional optical materials with temperature sensing and anti-counterfeiting properties play an essential role in the commercial applications. Herein, Mn2+/Nd3+ co-doped Cs2AgInCl6 (CAIC) lead-free double perovskites (DPs) is synthesized through a hydrothermal method, which exhibits visible to near-infrared (NIR) luminescence and reversible photochromic properties from yellowish to dark purple. The mechanism investigations on the photoluminescence and photochromic phenomena reveal that the incorporation of Mn2+ ions not only acts as an intermediary in the energy transfer process from the host exciton to Nd3+ ions, but also plays a pivotal role in the reversible photochromic response. The temperature-dependent luminescence, attributed to the contrasting thermal responses of Mn2+ and Nd3+ ions, enables precise temperature sensing via the fluorescence intensity ratio method. In addition, the integration of visible red emission, NIR luminescence, and photochromic properties in a single CAIC: Mn2+/Nd3+ DPs, offers a multilevel anti-counterfeiting strategy. The multifunctional CAIC: Mn2+/Nd3+ DPs would open up new avenues for advanced optical applications, particularly in the realms of temperature sensing and security anti-counterfeiting.

Rare earth (RE) ions-doped halide perovskites have emerged as highly promising materials for optoelectronics and photovoltaics due to their superior photoelectrical properties. However, their practical applications are limited by the intrinsic drawbacks such as stringent synthesis condition, poor stability, and low near-infrared (NIR) luminescence efficiency. Herein, we introduce a facile photo-induced method to synthesize CsPbCl1Br2: Yb3+ nanocrystals at room temperature, achieving the visible exciton recombination and the NIR Yb3+ luminescence. The integration of Ag nanocubes into the CsPbCl1Br2:Yb3+ nanocrystals significantly enhance the exciton recombination and Yb3+ luminescence, which is ascribed to localized surface plasmon resonance effects. Notably, the CsPbCl1Br2:Yb3+/Ag nanocomposites (NCs) exhibit excellent temperature-dependent fluorescence intensity ratio (FIR), lifetime, and full width at half-maximum (FWHM) characteristics, enabling them suitable for multimode temperature sensing. Furthermore, CsPbCl1Br2:Yb3+/Ag NCs display remarkably enhanced NIR luminescence, providing a high-efficiency luminescent material for phosphor-converted NIR light emitting diodes. This study presents a strategy for enhancing luminescence of perovskite-based optoelectronic materials by plasmonic engineering, thereby facilitating the advancement of high-efficiency light-emitting and sensing materials.

Halide perovskite nanocrystals (PeNCs) with their exceptional light absorption and tunable bandgap, are promising candidates for solar energy harvesting and high-performance photodetectors. However, the susceptibility of PeNCs to degradation limits their widespread application. The integration of halide perovskites within metal-organic frameworks (MOFs) has recently garnered significant attention as a strategy to create composite materials. The above encapsulation enhances the stability of perovskites against environmental stressors, such as humidity, temperature, and light, leading to improved performance characteristics. This paper provides a comprehensive review of perovskite-metal-organic framework composites (PeMOFs) and their applications in photoelectric conversion. It explores the various preparation methods for PeMOFs and highlights recent advancements in the field. The review examines the specific functions of MOFs within these composite materials and summarizes recent progress in a range of applications, including photocatalysis, sensing, light-emitting diodes, perovskite solar cells, luminescent anti-counterfeiting, information security, and detection. Finally, the paper discusses potential future trends and emerging applications for PeMOFs.

Rare-earth-doped all-inorganic perovskite applications for near-infrared (NIR) emission are crucial for the construction of the next generation of intelligent lighting sources. However, the preparation of rare-earth-doped all-inorganic perovskite is complex, and difficult to control, and the issue of thermal quenching poses significant challenges to its practical application. Here, in order to address these issues, a convenient photo-induced synthesis method for CsPbCl3:Mn/Yb nanocrystals (NCs) is proposed by decomposing carbon tetrachloride with 365 nm light to provide chloride ions and regulate the formation of perovskite at room temperature. The negative thermal quenching in the NIR emission is achieved through the energy transfer between Mn and Yb. The emission intensity of Yb enhances 3.2 times when the temperature rises to ≈427 K. Furthermore, with the help of the orange emission from the Mn2+ ions and the NIR emission from the Yb3+ ions, visible to NIR light emitting diode (LED) devices are constructed and applied in orange light illumination and night vision imaging. This study enriches the preparation methods and chemical research on perovskite doping, which may open up new opportunities for the widespread application of perovskite-based materials or device engineering.

Conducting polymers like polypyrrole, polyaniline, and polythiophene with nanostructures offers several advantages, such as high conductivity, a conjugated structure, and a large surface area, making them highly desirable for energy storage applications. However, the direct synthesis of conducting polymers with nanostructures poses a challenge. In this study, we employed a hard template method to fabricate polystyrene@polypyrrole (PS@PPy) core–shell nanoparticles. It is important to note that PS itself is a nonconductive material that hinders electron and ion transport, compromising the desired electrochemical properties. To overcome this limitation, the PS cores were removed using organic solvents to create hollow PPy nanospheres. We investigated six different organic solvents (cyclohexane, toluene, tetrahydrofuran, chloroform, acetone, and N,N-dimethylformamide (DMF)) for etching the PS cores. The resulting hollow PPy nanospheres showed various nanostructures, including intact, hollow, buckling, and collapsed structures, depending on the thickness of the PPy shell and the organic solvent used. PPy nanospheres synthesized with DMF demonstrated superior electrochemical properties compared to those prepared with other solvents, attributed to their highly effective PS removal efficiency, increased specific surface area, and improved charge transport efficiency. The specific capacitances of PPy nanospheres treated with DMF were as high as 350 F/g at 1 A/g. And the corresponding symmetric supercapacitor demonstrated a maximum energy density of 40 Wh/kg at a power density of 490 W/kg. These findings provide new insights into the synthesis method and energy storage mechanisms of PPy nanoparticles.

Cyanostilbene (CS)-related conjugated groups can be considered as dual functional groups of AIEgen and mesogen to construct photoluminescent liquid crystals, and it is essential to study the relationship between their molecular structures and compound properties systematically. In this paper, we designed and synthesized linear and bent-shaped CS derivatives containing ester- and amide-connecting groups and different substituted numbers of alkoxy tails. Their phase behaviors and photophysical properties were investigated in depth. The bent-shaped compounds with the mono-substituted alkoxy tail exhibit a smectic C structure, and those containing two or three alkoxy tails possess a hexagonal columnar phase structure. The compounds exhibit aggregation-induced emission (AIE) properties in tetrahydrofuran (THF)/water mixtures. When the water fraction increases to a certain threshold, a dramatic increase in emission intensity and a red-shift in the fluorescence emission peak are detected. The emission peaks of the ester-type compounds in solid states are around 480 nm, and those of the amide-type compounds are extended to 590 nm, exhibiting versatile luminescent colors. Moreover, thermochromic and photochromic fluorescence-responsive properties are witnessed in these CS derivatives. This work provides a new strategy for the design and synthesis of fluorescent liquid crystalline materials with multiple response properties.

All-inorganic perovskite nanocrystals (NCs) exhibit great promise in optoelectronics and photovoltaics. However, their intrinsic low-thermal/oxygen/moisture stability and the rigorous synthesis procedures have limited the practical applications. Here, we present a facile, one-step, light-induced method to synthesize CsPbCl3:Mn2+ NCs at room temperature by using carbon tetrachloride (CCl4) as the halide source. The corresponding formation mechanism of CsPbCl3:Mn2+ NCs is revealed, where CsPbCl3:Mn2+ NCs are formed through the direct incorporation of [MnCl6]4- octahedral into the perovskite lattice during the nucleation and growth process. Additionally, we demonstrate the in-situ growth of CsPbCl3:Mn2+ NCs within mesoporous silica (mSiO2) spheres to form CsPbCl3:Mn2+@mSiO2 nanocomposites via the light-induced method, resulting in a remarkable improvement in high-temperature and long-time stability. As a prototype experiment, a white light-emitting diode (WLED) device is constructed using CsPbCl3:Mn2+@mSiO2 nanocomposites, which exhibits a bright white-light emission with the CIE chromaticity coordinate of (0.352, 0.340). It is anticipated that light-induced synthesis method provides a straightforward strategy for synthesizing multifunctional halide perovskite nanocrystals and nanocomposites for versatile applications.

In this work, side-chain luminescent liquid crystalline polymers (SCLLCPs) that contain di-substituted cyanostilbene (CS) groups with different numbers of substituted terminal alkyl chains, namely PNB-Z-4, PNB-Z-34, and PNB-Z-345, were synthesized. Their mesomorphic structure, luminescence properties and photochromic luminescent behaviour were investigated. PNB-Z-4 containing one alkyl chain in each mesogen possesses a supramolecular oblique columnar (Colob) phase with large lattice parameters, which can transform into a lamellar structure at high temperature. PNB-Z-34 and PNB-Z-345 with two and three alkyl tails exhibit a hexagonal columnar phase (Colh) structure. Their fluorescence quantum yields (Phi F) in the solid state are improved by increasing the number of alkyl tails as well. PNB-Z-34 and PNB-Z-345 exhibit aggregation-induced emission (AIE) properties, while PNB-Z-4 shows weak fluorescence. Furthermore, their photochromic fluorescence responses are quite different. PNB-Z-4 exhibits an obvious "turn-on" photo-responsive behaviour with Phi F increasing from 0.70% to 7.73% after UV irradiation with the existence of [2 + 2] cycloaddition, while PNB-Z-34 and PNB-Z-345 show Z/E isomerization induced blueshift fluorescence response.

A class of polystyrene liquid crystalline polymer PS-n (n=2, 6, 8, 10, 12) with unconventional side chain structure was designed and synthesized. The influence of flexible spacer on the supramolecular columnar liquid crystalline phase formation was systematically studied. All polymers exhibit enantiotropic thermotropic liquid crystalline phase behaviour. When the flexible spacer is short (n <= 6), the polymer forms a two-dimensional supramolecular ordered oblique columnar (Colob) phase structure, which results from the periodic fluctuation of the one-dimensional layered structure caused by the ortho substitution of two biphenyl mesogens per side chain. As the spacer length increases (n >= 8), the polymer can exhibit two Col(ob) phases with different lattice parameters at different temperatures. The Col(ob)(I) phase with relatively small lattice parameter appeared near room temperature shows a characteristic undulated lamellar structure with oblique symmetry. With the increase of temperature, the polymer enters a higher ordered Col(ob)(II) phase with larger lattice parameter, showing the specific self-assembly behaviour at high temperature. When further increasing temperature, all polymers exhibit Col(ob) to lamellar phase transition before entering isotropic state. The existence of long spacer length tends to promote the self-organization behaviour of side chain, which makes the appearance of highly ordered mesophase. Due to the parallel orientation of columnar structure, the fingerprint-like morphology can be found on the surface of thermal annealed PS-n thin film, and the macroscopic orientation can occur along the shear direction under shear induction. [GRAPHICS] .

Printable organic semiconducting single crystals (OSSCs) offer tantalizing opportunities for next-generation wearable electronics, but their development has been plagued by a long-standing yet inherent problem─spatially uncontrolled and stochastic nucleation events─which usually causes the formation of polycrystalline films and hence limited performance. Here, we report a convenient approach to precisely manipulate the elusive molecule nucleation process for high-throughput inkjet printing of OSSCs with record-high mobility. By engineering curvature of the contact line with a teardrop-shaped micropattern, molecule nucleation is elegantly anchored at the vertex of the topological structure, enabling formation of a single nucleus for the subsequent growth of OSSCs. Using this approach, we achieve patterned growth of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene single crystals, yielding a breakthrough for an organic field-effect transistor array with a high average mobility of 12.5 cm2 V-1 s-1. These findings not only provide keen insights into controlling molecule nucleation kinetics but also offer opportunities for high-performance printed electronics.

Cholesteric liquid crystal elastomers (CLCEs) can change structural colour in response to mechanical stimuli, which can be applied as sensors and optical devices. Thus, the facile fabrication of large-area CLCE films is critical but challenging. Herein, a simple procedure for the preparation of CLCE films by adding a chain-transfer agent is reported. When the CLCE films are fixed between two thermoplastic polyurethane (TPU) films, the obtained TPU/CLCE/TPU sandwich films exhibit mechanochromic behaviours. Due to the decrease of the helical pitch of CLCE film upon stretching, the selective Bragg reflection band shifts to short wavelength. Based on this structural colour change, a flower pattern can emerge or vanish upon stretching. Moreover, a two-dimensional tetragonal grating with elasticity is prepared. The TPU/CLCE/TPU films can be facilely fabricated over large area and used as car films.

Large‐area organic–inorganic hybrid perovskite (OIHP) single crystals have attracted intensive interest for diverse device applications. However, conventional growth methods usually suffer from limited and disordered mass transport in the crystal growth process, making the large‐area fabrication of OIHP single crystals with controllable thickness remain a formidable challenge. Here, for the first time, a three‐dimensional confined crystallization (3DCC) strategy is reported to achieve centimeter‐scale growth of a OIHP single‐crystal array with tunable thickness. The 3D geometrical channels can not only induce an oriented capillary flow to enhance the mass transport by up to 100 folds, but also can effectively confine the crystal crystallization in both in‐plane and out‐of‐plane directions, thereby remarkably improving the crystallinity and thickness control of the crystals. Furthermore, a self‐driven lateral‐structured photodetector is demonstrated based on the resultant OIHP single‐crystal array with significant long‐term stability (>36 days, maintaining 80% of the initial performance) and outstanding device performance (linear dynamic range of 73 dB). The ability of the 3DCC strategy to scale up the growth of high‐quality perovskite single crystals opens a pathway for large‐scale and integrated optoelectronic applications.

alpha-Cyanostilbene derivatives are known as fluorescent photochromic molecules that could be used to realize emission colour change or on/off switching via photo-induced isomerization or cycloaddition. Comparing with isomerization, photocycloaddition is less studied due to its critical molecular position and alignment requirement for molecular packing. In this work, biphenyl-based cyanostilbenic compounds 1-3 were synthesized, which exhibit characteristic mechanofluorochromic (MFC) response behaviour. Under force stimuli, the luminescent colour has bathochromic shift from blue to green, together with the phase transition from crystal to amorphous state. Photochromic fluorescent response attributed to photo-induced [2 + 2] cycloaddition could take place instantly in amorphous state, rather than crystals. The MFC response can be successfully used to monitor the photoreaction process, giving rise to quantitative dimerized product. The single crystal structure of compound 2 revealed its photostable feature. The formation of excimers in ground amorphous state, together with the mechanical shearing, facilitates the occurrence of cycloaddition. Subsequently, the recovery process could be achieved thermally or under UV irradiation.

Artificial photonic materials based on chiral liquid-crystalline nanostructures have attracted increasing interests for their wide applications as sensors, anti-counterfeit measures, displays and colour filters. Although the structurally coloured films with chiral nematic structures or blue phases have been prepared, the ones fabricated by fixing chiral smectic C (SmC*) phases have been rarely reported. In this work, organic-inorganic hybrid silica (OIHS) films with a SmC* structure were reported for the first time. An organosilane (CSC) with an enantiotropic SmC* phase was synthesized. The OIHS films with a SmC* structure were fabricated by the polycondensation of CSC under an acidic condition. The colour patterns can be observed in the oblique view, but not be observed in the vertical view, which is mainly due to the light scattering of the nanoparticles on film surface and the selective Bragg reflection of film inside. Therefore, such properties make the OIHS films promising candidates for anti-counterfeiting applications.

Abstract Printable organic semiconducting single crystals (OSSCs) offer tantalizing opportunities for next-generation wearable electronics, but their development has been plagued by a long-standing yet inherent problem—spatially uncontrolled and stochastic nucleation events, which usually causes the formation of polycrystalline films and hence limited performance. Here, we report a convenient approach to precisely manipulate the elusive molecule nucleation process for one-step inkjet printing of OSSCs with record-high mobility. By engineering curvature of contact line with a teardrop-shaped micropattern, molecule nucleation is elegantly anchored at the vertex of the topological structure, enabling formation of a single nucleus for the subsequent growth of OSSC. Using this approach, we achieve patterned growth of 2,7-dioctyl[1]benzothieno[3,2-b][1] benzothiophene single crystals, yielding a breakthrough for organic field-effect transistor array with high average mobility of 12.5 cm2 V-1 s-1. These findings not only provide keen insights into controlling molecule nucleation kinetics, but also offer unprecedented opportunities for high-performance printed electronics.

Fullerene (C 60 ) single crystals with exceptionally low defects and nearly perfect translational symmetry make them appealing in achieving high‐performance n‐type organic transistors. However, because of its natural 0D structure, control over continuous crystallization of C 60 over a large area is extremely challenging. Here, the authors report a solution‐phase epitaxial approach for wafer‐scale growth of continuously aligned C 60 single crystals. This method enables the rational control of the density of nucleation event at meniscus front by confining the size and shape of meniscus with a microchannel template. In this case, a single nucleus as seed crystal can be formed at the front of meniscus, and then epitaxial growth from the seed crystal occurs with continuous retreat of the meniscus. As a result, highly uniform C 60 single‐crystal array with ultralow defect density is obtained on 2‐inch substrate. Organic field‐effect transistors made from the C 60 single‐crystal array show a high average electron mobility of 2.17 cm 2 V −1 s −1 , along with a maximum mobility of 5.09 cm 2 V −1 s −1 , which is much superior to the C 60 polycrystalline film‐based devices. This strategy opens new opportunities for the scalable fabrication of high‐performance integrated devices based on organic crystals.

Copolymerization is an effective approach to tailor the thermal and structural properties of liquid crystalline polymer materials, which is essential for various applications. In this work, two series of polynorbornene copolymers, A-r-B and A-r-C, with the biphenyl mesogenic side group at different substituent positions were synthesized via ring-opening metathesis polymerization in various compositions. The corresponding homopolymers A and C are liquid crystalline polymers, exhibiting an oblique columnar structure (Colob/p2) and lamellar structure, respectively, while homopolymer B is amorphous. The composition-dependent phase behaviors of copolymers were systematically studied with the combination of SAXS, GISAXS, AFM, DSC and POM techniques. With increasing molar content of A (xA), the self-organzied structure of copolymer A-r-B follows the sequence from amorphous to lamellar, undulated lamellar, and Colob/p2 structures, and that of A-r-C follows the sequence of lamellar, undulated lamellar, and Colob/p2 structures. Then, copolymers with undulated lamellar or Colob/p2 structures tend to enter lamellar phase first at higher temperature and then change to the isotropic state during heating. The composition-induced transition from lamellar to supramolecular columnar organization is somewhat reminiscent of block copolymers and other soft matter systems that can form ordered structures. Furthermore, the subsitituent number and position of rigid mesogenic units in the side chain can further modify the morphologies of self-organized phases.