Abstract Ferroelectric nematic fluids are promising materials for tunable nonlinear photonics, with applications ranging from second harmonic generation to sources of entangled photons. However, the few reported values of second‐order susceptibilities vary widely depending on the molecular architecture. Here, we systematically measure second‐order NLO susceptibilities of five different materials that exhibit the ferroelectric nematic phase, as well as the more recently discovered layered smectic A ferroelectric phase. The materials investigated include archetypal molecular architectures as well as mixtures showing room‐temperature ferroelectric phases. The measured values, which range from 0.3 to 20 pm V −1 , are here reasonably predicted by combining calculations of molecular‐level hyperpolarizabilities and a simple nematic potential, highlighting the opportunities of modelling‐assisted design for enhanced NLO ferroelectric fluids.

Abstract Over the past few decades, organic light‐emitting diodes (OLEDs) have demonstrated compelling technological advantages due to their ability to directly convert electrons into photons without requiring backlighting, thereby offering self‐emissive surfaces, ultrathin device profiles, compatibility with flexible substrates, high luminance, and exceptional contrast ratios (achieving true black). Today, OLEDs dominate the market for small‐scale displays such as smartphones and laptops. Propelled by the burgeoning ubiquity of the Internet of Things, OLEDs are poised to experience an exponential upsurge in prospective exigency. However, conventional thermal evaporation techniques face challenges in achieving uniform large‐area OLED fabrication, rendering mass production costly and complex—a persistent drawback hindering OLEDs from becoming the undisputed market leader. Amidst this milieu, inkjet printing (IJP) has magnetized considerable scholarly and commercial traction across the panoply of fabrication modalities, crystallizing as the pre‐eminent candidate for scalable, large‐area OLED manufacturing. This technique boasts non‐contact processing, high material utilization, and compatibility with roll‐to‐roll manufacturing. In this review, the critical parameters governing ink formulation are delineated and provide an overview of prevailing OLED device architectures. Subsequently, recent advancements are consolidate in inkjet‐printed OLED layers, culminating in a circumspect prognosis of the extant impediments and the prospective trajectory toward wholly inkjet‐patterned OLED architectures.

Abstract A perchlorination strategy is introduced as a novel approach for designing Cu(I)‐based deep‐red TADF materials exhibiting large negative thermal quenching (NTQ). Replacing the 1,10‐phenanthroline (phen) ligand in conventional [Cu(phen)(P^P)]⁺ complexes with octachloro‐1,10‐phenanthroline (phenCl 8 ) unexpectedly induces a strong NTQ effect while simultaneously triggering a giant bathochromic shift in absorption, excitation, and emission. Whereas the parent complex [Cu(phen)(DPEPhos)]PF 6 emits at λ max = 576 nm with nearly temperature‐independent emission intensity in the 77–300K range ( I 300 K / I 77 K = 1.1), its perchlorinated analog [Cu(phenCl 8 )(DPEPhos)]PF 6 exhibits deep‐red emission (λ max = 680 nm) and a remarkable NTQ effect with the impressively high ratio I 300 K / I 77 K of 12.3. Detailed investigations reveal that the NTQ behavior stems from perchlorination‐induced spin‐orbit coupling enhancement, which facilitates non‐radiative T 1 → S 0 decays at low temperatures. Additionally, perchlorination boosts X‐ray luminescence intensity, further highlighting its potential for optoelectronic applications.

Abstract Recent investigations into the bandgap evolution of hybrid perovskites under hydrostatic pressure have primarily focused on the room‐temperature cubic phase of methylammonium lead bromide (MAPbBr 3 ), leaving its low‐temperature behavior largely unexplored. In this work, the pressure response of MAPbBr 3 single crystals is investigated over a broad temperature range using photoluminescence (PL), cathodoluminescence (CL), and density functional theory (DFT) calculations. Hydrostatic pressure is shown to modify the electronic structure of MAPbBr 3 across cubic (280 K, 260 K), tetragonal (210, 170 K), and orthorhombic (120, 80 K) phases, quantified via the bandgap pressure coefficient ( α ). The experimentally obtained α values are: α 280K,260K = −47 ± 3 meV GPa −1 , α 210K,170K = −48 ± 3 meV GPa −1 , α 120K,80K = −90 ± 3 meV GPa −1 . The pressure coefficient calculated theoretically within the DFT calculations at zero temperature is −100 ± 2 meV GPa −1 . The increasingly negative α values observed with decreasing temperature reflect the suppression of inorganic cage phonon activity and the reduced orientational freedom of MA + cations. These findings highlight the crucial influence of molecular dynamics and the interplay between organic and inorganic sublattices in governing the pressure response of hybrid perovskites across different structural phases.

Abstract Dynamic control of light, and in particular beam steering, is pivotal in various optical applications, including telecommunications, LiDAR, and biomedical imaging. Traditional approaches achieve this by interfacing a tunable modulating device with an external light source, facing challenges in achieving compact devices. Here, a dynamic photoluminescence (PL) modulating device is introduced, with which the properties of light directly emitted by a quasi‐2D perovskite (in particular, its directionality and polarization) can be modified continuously and over a large range. The device is based on a liquid‐crystal‐tunable Fabry‐Perot (FP) nanocavity and uses the FP energy‐momentum dispersion and spin‐orbit coupling between the excitons and the cavity modes to enable this dynamic control over the emitted radiation. With this device, electrically‐controlled, continuous, and variable emission angles are achieved up to a maximum of 28°, as well as manipulation of the PL polarization state, enabling both the creation of polarization gradients and the achievement of angle‐specific polarization conversion. Moreover, due to its resonant character, a threefold increase in the emission intensity is observed. This approach leverages the unique properties of actively tunable birefringent nanocavities to improve emission directivity, angle tunability, and polarization control, presenting a promising solution for next‐generation, deeply integrated beam steering devices.

Abstract Magnetic interfacial exchange bias, as a key control method for spintronic devices, remains unclear in terms of its ultrafast dynamic behavior and its role in regulating spintronic terahertz emissions. In this work, femtosecond optical pulses are used to excite ferromagnetic/antiferromagnetic bilayer films with interfacial exchange bias, and a significant modulation phenomenon of terahertz emission is observed by comparing samples with different magnetization pinning states induced by exchange bias. Through the measurement of dynamic hysteresis loops under femtosecond optical pulse excitation, it is confirmed that the optical pulse can rapidly break and then recover the exchange bias within the picosecond time scale. This transient reconstruction process of exchange bias effectively enhances the ultrafast spin precession signal at ≈2 THz, while suppressing the ultrafast demagnetization‐related signal at ≈0.77 THz. By exploiting the difference in flip symmetry of the samples, this is found that the photo‐introduced magnetization dynamics process dominated the modulation effect of the exchange bias on the two frequency bands. These results reveal that picosecond‐scale transient exchange bias can regulate both the frequency content and coherence of spintronic terahertz emission, offering a pathway toward tunable terahertz spintronic sources.

Abstract Effects of precursor and ligand of carbon dots (CDs)‐based composites on tuning their optical properties have been extensively studied. However, comprehensive research on a precursor that can also work as a ligand is currently lacking, which is important for their further development. In this study, CDs@boron oxide (CDs@B 2 O 3 ) is structurally and optically regulated using naturally sourced sodium lignosulfonate (SL) in two ways. As a co‐precursor, SL enables structural rigidity and luminescent group‐oriented regulation of CDs. When serving as a co‐ligand, SL can help B 2 O 3 effectively encapsulate and confine CDs, benefiting the harvest of triplet excitons to enhance stimulated emission. Meanwhile, yellow‐green fluorescence is observed, along with an impressive aqueous quantum yield ≤35.07%, lifetimes up to 358 ms, and thermally activated delayed fluorescence. After further coating CDs@B 2 O 3 onto an alternating‐current light‐emitting diode, stable and gentle white lighting is easily witnessed at the Commission Internationale de L'Eclairage coordinates at (0.33, 0.34). Overall, this work is anticipated to pave the way for widening the synthetic strategy of carbon dots‐based afterglow composites.

Abstract Stealth materials with single composition are facing challenges to meet the urgent demands in advanced anti‐detection technologies. How to combine the ability of high microwave absorption (MA) with low infrared (IR) emissivity performance in one material is the key point. Herein, the core‐shell PBA@C@ITO nanocubes are innovatively prepared by polycondensation and co‐precipitation. These nanocubes are characterized with enhanced multifunctional properties showing a minimum reflection loss (RL min ) at −45.96 dB, an effective absorption bandwidth (EAB) of 6 GHz. More remarkably, the average IR emissivity of PBA@C@ITO‐40 wt%/PEI film in 3–5 µm and 8–14 µm is as low as of 0.195 and 0.286, respectively. Thanks to the introduction of indium tin oxide (ITO), which enables to achieve impedance matching and enhances multiple loss modes while significantly reducing IR emissivity. Thus, this promising work provides a solid foundation for the research of advanced multifunctional stealth materials. Furthermore, this work emphasizes the necessity of decoupled testing under realistic multi‐field conditions to accurately validate the intrinsic compatibility of MA and IR stealth performance, pointing toward future experimental platforms for synchronized evaluation.

Abstract Spatial control of memory effects in soft matter photonic crystals is a key challenge for reconfigurable optics. Here, a patterned blue phase liquid crystal (BPLC) device that exhibits localized, electrically‐driven bistability is demonstrated, achieved through a cost‐efficient photolithographic fabrication method. The innovative dual‐alignment design, utilizing two distinct commercial alignment materials, ensures strong anchoring stability while reducing fabrication complexity. This architecture yields regions with markedly different electro‐optic responses: hybrid‐aligned areas support conventional analog modulation, while vertically‐aligned regions within the BPII phase exhibit a non‐volatile memory effect. This enables switching between a high‐contrast patterned state and a uniform reflective state. Furthermore, a repetitively applied field (RAF) protocol is introduced mitigates field‐induced crystal degradation in the BPI phase, thereby enhancing device longevity and reliability. By enabling spatially programmable bistability across multiple liquid‐crystal phases, the approach opens new pathways for advanced photonic systems that integrate memory and display functionalities in a single platform.

Abstract PbS quantum dots (QDs) are promising materials for short‐wave infrared (SWIR) photodetectors due to their tunable bandgap and broad spectral absorption. This study explores the impact of trioctylphosphine (TOP)‐mediated surface reconstruction on PbS QDs, revealing that the TOP treatment enhances QD surface morphology, reduces trap states, and improves QD stacking behavior in solid films. Notably, a diode‐type photodetector based on TOP‐treated QDs exhibits a significantly enhanced specific detectivity ( D *) of 2.07 × 10 11 Jones at 1290 nm, which is 50 times higher than that of devices using conventional QDs. It also shows a marked reduction in dark current density to 237 nA cm −2 at −0.5 V. Furthermore, the TOP‐QD photodetector demonstrates improved storage stability under non‐encapsulated conditions, underscoring the effectiveness of TOP‐mediated surface reconstruction in enhancing both performance and reliability. This work offers valuable insights into the surface engineering of PbS QDs and presents a pathway for the development of high‐performance, solution‐processed SWIR imaging systems and environmental monitoring technologies.