Ying Lv

Inkjet printing offers a promising non‐contact route toward high‐throughput, large‐area manufacturing of functional films for next‐generation optoelectronic devices. However, the broader adoption in continuous production lines is hindered by the coffee‐ring effect that compromises film uniformity. Additionally, existing printable inks rely predominantly on nanoscale particles (2 V ₆ O ₁₆ ·1.5H ₂ O (KVO) and a water/1,2‐propylene glycol (1,2‐PG) cosolvent system. The optimized ink exhibits excellent rheological properties for stable ejection, even with micron‐sized particles. Critically, the 1,2‐PG effectively inhibits the coffee‐ring effect by reducing the surface tension, allowing uniform deposition of large particles without the use of insulating surfactants. Therefore, a continuously patterned electrochromic film can be directly printed, which exhibits reversible multicolor transitions and remarkable cycling stability. Furthermore, we assembled a large‐scale electrochromic device (21.0 × 29.7 cm ² ) with a complex pattern based on the printed KVO film, which demonstrates uniform and reversible color changes across the active area. Our ink formulation offers a green, surfactant‐free alternative to traditional electrochromic inks and demonstrates that large‐sized functional particles can be uniformly printed via synergistic Marangoni flow and viscosity control, expanding the material scope for inkjet‐printed electrochromic devices.

Semi‐transparent organic photovoltaics (ST‐OPVs) are promising for aesthetic building‐integrated applications but face key challenges in balancing color quality with photovoltaic performance. Herein, we present programmable photovoltaic windows based on double‐sided dielectric/metal/dielectric (DMD) architectures. This innovative design creates a tunable optical microcavity that enables broad‐spectrum color control, delivering a vibrant and customizable appearance while maintaining high visible light transparency and efficient infrared heat blocking. As a result, approximately 60% of the sRGB gamut can be significantly expanded and a high color rendering index (CRI) up to 89.8 is achieved. Combined with a bottom MoO ₃ annealing strategy to enhance electrode transmittance, the optimized ST‐OPV device achieves a remarkable balance between aesthetic and functional performance: a power conversion efficiency of 10.07% and an average visible transmittance of 35.9% with high CRI. Importantly, these devices integrate wide gamut and high CRI programmability together with outstanding thermal management capability, providing a promising strategy for multifunctional ST‐OPVs that meet the stringent requirements of aesthetic, energy‐efficient building facades.

Au nanoparticles/WO ₃ heterofilms combine localized surface plasmon resonance and built-in electric field enable ultrafast, efficient and flexible electrochromic smart windows.

Transparent display technology is emerging as a pivotal direction for the future of the display industry. Metal halide perovskite materials, known for their outstanding optoelectronic properties, hold considerable promise for application in transparent perovskite light-emitting diodes (TPeLEDs). Nevertheless, the realization of high-performance TPeLEDs is still hindered by two major challenges: interfacial issues between the hole-injection layer (such as PEDOT: PSS) and the perovskite layer, and the difficulty of fabricating high-quality top transparent electrodes. In this work, we introduce a straightforward post-treatment strategy using methanol (MeOH) to simultaneously optimize the physical morphology, chemical composition, and electrical characteristics of PEDOT: PSS films. Results demonstrate that MeOH treatment effectively removes excess insulating PSS components from the PEDOT: PSS surface, yielding a smoother, more hydrophobic film with significantly enhanced conductivity. This optimized interface promotes the formation of a CsPbBr₃ perovskite layer with improved crystallinity, more uniform coverage, and reduced defect density, thereby facilitating the subsequent deposition of a high-quality transparent top electrode. Benefiting from these improvements, the resulting transparent green TPeLED exhibits outstanding overall performance: a maximum total external quantum efficiency (EQE) of 7.35% and an average visible transmittance of 63.51%. Additionally, the device shows significantly enhanced current efficiency, spectral stability, and operational lifetime. This study offers a simple yet effective approach to addressing key interfacial issues in TPeLEDs, advancing the application of perovskite materials in transparent displays.

Electrically pumped organic edge-emitting lasers face a fundamental trade-off between optical confinement and electrical injection losses, hindered by the low refractive index contrast of organic layers and severe plasmonic absorption from metallic electrodes in conventional waveguides. Here, we demonstrate a single-sided Bragg reflection waveguide (BRW) architecture to overcome these constraints. By exploiting photonic bandgap confinement, this structure achieves efficient transverse resonance within a low-index organic film (CBP:BSBCz) independent of total internal reflection. The resulting device exhibits amplified spontaneous emission at 465.1 nm, featuring a low threshold of ∼4.45 µJ cm ^-2 , a narrow FWHM of 2.30 nm, and dominant TE polarization. Comprehensive simulations and experiments confirm that the BRW mode provides enhanced mode confinement and lower propagation loss compared to conventional waveguide modes. Consequently, this architecture effectively isolates the optical mode from the top metal contact, establishing a robust design pathway for future electrically driven organic lasers.

A hetero-order coupled cavity architecture is introduced for the first time into multicolor electrochromic mirrors for simultaneous realization of high-purity, wide-gamut, and broad-viewing-angle electrochromic displays.

Multiresonance thermally activated delayed fluorescence (MR-TADF) materials, characterized by narrowband emission and high exciton utilization efficiency, have emerged as promising gain media for organic semiconductor lasers. However, achieving low-threshold lasing...

Multi‐band electrochromic (MBEC) smart windows, capable of selectively modulating solar and thermal radiation from visible (VIS) to mid‐/long‐wave infrared (MWIR/LWIR), show significant potential for energy‐efficient buildings and carbon neutrality. Yet this potential remains unrealized due to the inherent limitations of high‐performance electrochromic materials and electrodes. Herein, we pioneer an MBEC smart window by integrating amorphous/nanocrystalline biphasic tungsten trioxide heterojunction (a,c‐WO ₃ ) film with a gradient porous indium tin oxide (GP‐ITO) electrode. The nanostructured biphasic heterojunctions effectively enhance the localized surface plasmon resonance (LSPR) and spontaneously create built‐in electric fields at the heterointerface, enabling efficient optothermal modulation with rapid electron/ion transport kinetics. The dense/porous bilayer GP‐ITO electrode overcomes the trilemma of conductivity, VIS/NIR transmittance, and IR emissivity, boosting modulation range and amplitude. Consequently, the GP‐ITO/a,c‐WO ₃ film (1.8 × 1.8 cm ² ) exhibits remarkable MBEC performance including high optical contrast (71.7%@620 nm, 85.5%@1560 nm, 70.5%@2500 nm), rapid switching (12.4/15.4 s for coloration/bleaching), excellent durability (> 8000 cycles), and notable emissivity/temperature regulation (0.61/0.59 at MWIR/LWIR, 13.8°C). A 5 × 5 cm ² prototype smart window demonstrates a 15.3°C indoor temperature reduction under AM 1.5G solar irradiation during mode switching. This work offers an effective strategy for MBEC materials/devices in zero‐carbon buildings, dynamic optothermal management, and adaptive camouflage.

Multi‐band electrochromic (MBEC) smart windows, capable of dynamic and selective management of solar radiation (visible and near‐infrared transmittance) and thermal radiation (mid‐ and long‐wave infrared emissivity), are crucial for zero‐energy buildings and adaptive optical systems. However, they have not yet been developed due to the inherent material design challenges and kinetics‐stability trade‐offs. Inspired by lotus root vessels, we develop vertically aligned nano‐helix tungsten oxide (NH‐WO ₃ ) films with amorphous‐crystalline heterophase. The multiscale microstructure provides numerous active sites, enhances local electric fields, and alleviates stress during repeated cycling. Consequently, NH‐WO ₃ achieves unprecedented quad‐band electrochromic performances with multi‐mode photothermal modulation across the visible to long‐wave infrared spectra, featuring large optical contrast (Δ T _VIS–NIR ~79%), significant temperature and emissivity variation (Δ T = 9.3 °C, Δ ε = 0.47@5 μm), ultrafast switching (3.9/1.9 s@780 nm, 2.8/2.5 s@990 nm), and robust cyclability (10 000 cycles with only 9.1% optical‐contrast loss). Furthermore, a prototype smart window based on the NH‐WO ₃ film maintains a comfortable indoor temperature of 26 °C even under continuous AM 1.5G solar irradiation for 1 hour. This bio‐inspired nano‐helix design provides an efficient strategy for the development of advanced next‐generation photothermal management smart windows toward practical energy‐efficient architectures and adaptive optics.