Indium phosphide quantum dots (InP QDs) are premier candidates for environmentally friendly displays, yet their industrial utility is limited by complex, multistep synthesis methods requiring intermediate purification. Here, we present a kinetic control and ligand synergy strategy enabling the centrifugation-free, one-pot synthesis of high-performance green InP/GaP/ZnS QDs. By pinpointing the nucleation temperature (250 °C) and optimizing the In:myristic acid ratio (1:4), we establish a dynamic ligand environment that successfully suppresses oxidized indium species (InPOx) formation and nonradiative recombination, as validated by X-ray photoelectron spectroscopy. The resulting green-emitting InP/GaP/ZnS QDs achieved an outstanding photoluminescence quantum yield (PLQY) of 86% and a narrow full width at half-maximum of 44 nm, representing the highest reported PLQY for one-pot synthesized InP QDs with GaP intermediate shells. Quantum dot light-emitting diodes fabricated with these QDs demonstrate stable electroluminescence at 535 nm, achieving a maximum external quantum efficiency of 3.02% and a current efficiency of 12.14 cd A–1. This scalable, centrifugation-free approach effectively bridges the performance gap between one-pot and multistep synthesis, offering a viable pathway toward the industrial manufacturing of environmentally benign QDs for display and lighting applications.

Quantitative phase imaging has emerged as an essential tool for bioimaging, semiconductor wafer defect inspection, and material metrology. In particular, the drive toward compact and portable phase imaging systems is crucial for extending the reach of these powerful techniques to point-of-care diagnostics and inline surface profile measurement. In this work, we propose and demonstrate a polarization-multiplexed metasurface-enabled diffraction phase microscopy system for quantitative phase imaging. The metalens performs a Fourier transform and simultaneously separates two orthogonal polarizations in the Fourier plane, generating the object (x-polarized) and reference (y-polarized) waves, respectively. We first validated the system’s phase-imaging capability integrated with a standard microscope. Crucially, we then demonstrated its ability to operate as a compact, standalone system without a microscope. We envision that the proposed compact system will catalyze new applications in diverse fields, such as point-of-care diagnostics, in situ industrial monitoring, and in-line surface metrology.

Vectorial Doppler metrology exploits spatially varying polarization structures to enable direction-sensitive angular velocimetry, offering capabilities beyond those of scalar Doppler schemes. However, applying such vectorial strategies within nonlinear detection frameworks remains challenging, as conventional frequency-conversion processes are inherently polarization-dependent and tend to distort the vectorial topology that encodes directional Doppler information. In this work, we overcome this fundamental limitation by introducing a spatial-polarization-independent upconversion scheme that preserves the full vectorial structure of rotational Doppler signals. This allows for infrared Doppler polarization signals to be conformally translated into the visible domain while retaining their directional sensitivity. Within this preserved vectorial framework, we realize direction-resolved rotational velocimetry through two complementary detection approaches: a commonly employed polarization differential detection method and a newly proposed polarization heterodyne detection scheme that provides a compact and robust time–frequency route to retrieving the rotation direction. These results establish a practical pathway for vectorial Doppler sensing under nonlinear frequency conversion and highlight the broader utility of multidimensional optical degrees of freedom for robust, high-fidelity multiparameter measurement.

Phenylethylammonium (PEA) organic spacer-based quasi-two-dimensional (Q-2D) perovskites have garnered considerable attention due to their tunable optoelectronic properties and high environmental stability. However, the response speed and responsivity of PEA-based Q-2D perovskite photodiodes (Q-2D PPDs) remain limited by inadequate carrier transport and collection. Herein, we propose a simple yet effective crystal orientation control strategy to overcome these limitations. Compositional engineering of the photoactive layer is employed to suppress defect formation and promote out-of-plane crystal orientation, which facilitates carrier transport in vertical n–i–p photodiodes. Concurrently, the optimized surface morphology of the Q-2D perovskite film enables the implementation of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) as a hole transport layer to enhance hole extraction, block interfacial electron injection, and reduce dark leakage current. Our self-powered Q-2D PPDs, featuring a device architecture of ITO/SnO2/(4F-PEA)2(MA)3Pb4I11Cl2/PTAA/Au, exhibit ultrafast response times of 2.5 μs/1.9 μs (rise/fall), a responsivity of 0.25 A/W, and a detectivity of 3.4 × 1012 Jones at 550 nm. Notably, the unencapsulated detectors show excellent operational stability for over 180 days under ambient conditions. The remarkable detection performance of the Q-2D PPDs was further demonstrated in image sensing and indirect X-ray detection, showcasing their potential for versatile optoelectronic applications.

Shortwave infrared light sources are indispensable for various applications, including advanced imaging, spectroscopy, and sensing, yet their widespread adoption is limited by the high cost of epitaxial semiconductors, such as InGaAs. Downconverters (DCs) offer a cost-effective alternative, and quantum dots (QDs) stand out due to their high photoluminescence quantum yield, size-tunable emission, and solution processability. However, QD-DCs suffer from performance degradation under high excitation power densities due to significant heat generation in the process of light absorption. Here we have developed high-power, stable, and spectrally tunable narrowband and broadband SWIR DCs (1000-1600 nm) based on Lead sulfide QDs. By mixing two different-sized QDs, we exploit Förster resonance energy transfer and photon reabsorption to realize a binary system with a high photoluminescence quantum yield of 35%. Embedding the QDs in a poly-(methyl methacrylate) host mitigates local thermal stress on the QDs, enabling standalone DCs with a high emission power density (EmPD) of 110 mW/cm2 at 1380 nm. Further optimization with a spectrally selective distributed Bragg reflector for enhanced light extraction and a sapphire substrate for efficient heat dissipation, we achieved a record EmPD of 385 mW/cm2 at 1380 nm with optical power conversion efficiency of 10% and operational stability above 230 h at an EmPD of 190 mW/cm2. This demonstrates a scalable route to low-cost SWIR light sources, narrowing the performance gap between solution-processed DCs and conventional epitaxial semiconductors.

Resonant metasurfaces, characterized by their compact integration and strong field localization, combined with the superior nonlinear properties of low-dimensional materials, provide a promising platform for developing more efficient and integrated nonlinear devices. Enhancing nonlinear conversion efficiency is crucial; at the same time, integrating multiple functionalities into a single compact design is also urgently demanded for versatile nonlinear optical devices. In this work, we propose a polarization-independent quasi-bound state in continuum (q-BIC) metasurface integrated with a thin layer 3R-MoS2, which enables giant enhancement of second harmonic generation (SHG), as well as full-Poincaré polarization tunability of SHG emission by precisely controlling the polarization of the fundamental wave. Our work paves the way for tailoring exceptional optical nonlinearity and tunable polarization control in nonlinear light sources.

Polarization-dependent nonreciprocal behavior of integrated optical isolators plays a significant role in the functionality of photonic integrated circuits. However, conventional magneto-optic (MO) isolators based on the Faraday effect suffer from high propagation loss and fabrication complexity. Here, we demonstrate an integrated magnetic-free nonreciprocal polarization rotation device based on acousto-optic (AO) scattering, implemented on an X-cut thin-film lithium niobate (TFLN) platform. Unlike magneto- or electro-optic configurations, our device employs electrically driven surface acoustic waves to facilitate energy and momentum conversion between fundamental polarization mode pairs. By leveraging the inherent anisotropy of TFLN, efficient interpolarization conversion and large single-sideband suppression are achieved. Furthermore, a folded four-port configuration is designed to extend the AO interaction length, thereby demonstrating nonreciprocal optical propagation. The device achieves a high nonreciprocal contrast exceeding 20 dB and demonstrates a broad operational bandwidth of more than 150 GHz within the optical C band. Additionally, the optimized device exhibits a figure of merit (FoM) greater than 8 rad/dB, approximately 1 order of magnitude higher than that of state-of-the-art on-chip MO devices. These findings provide a promising route toward developing broadband nonmagnetic integrated optical isolators and enabling efficient polarization rotation or frequency conversion on other anisotropic material platforms.

Addressing the substantial energy consumption from building heating and cooling is critical for climate change mitigation. Passive daytime radiative cooling (PDRC) offers a highly promising zero-energy strategy to mitigate global warming; however, it encounters several key limitations, including susceptibility to overcooling, constrained environmental adaptability, and challenges in manufacturability. Herein, we develop a trimode multicolor thermochromic canopy with distinct microsphere-rich and pore-rich zones in orthogonal polytetrafluoroethylene (PTFE) fibrous membranes. This design achieves programmable multitemperature spectral responses, including high mid-infrared emissivity (0.94) in the atmospheric transparency window, competitive near-infrared reflectance (93.7%), and visible light modulation capability of 30.44% via polychromic thermochromic microcapsules (TMs). Promisingly, our PTFE/TM composite enables three autonomous operational modes, yielding a maximum subambient daytime cooling of 7.6 °C in hot conditions, heating of 5.4 °C in cold conditions, and a stable intermediate state at comfortable temperatures. The composite also exhibited excellent durability and superhydrophobicity. EnergyPlus simulations confirm the significant global potential, showing substantial annual energy savings and CO2 emission reductions across diverse climates, outperforming static cooling materials by effectively avoiding overcooling penalties. This work provides a viable zero-energy pathway for mitigating urban heat island effects and promoting climate-resilient building thermal regulation.

The ability to optically trap and manipulate artificial microswimmers, such as active Janus particles (JPs), provides a breakthrough in active matter research and applications. However, it presents significant challenges because of the asymmetry in the optical properties of JPs and remains incomprehensible. Illustrating the interplay between optical and thermophoretic forces, we demonstrate dynamically stable optical trapping of Pt-silica JPs, where the force-balanced position evolves spontaneously within a localized volume around the focal point and in a vertically shifted annular confinement at low and high laser powers, respectively. Intriguingly, the orientational and orbital dynamics of JP remain strongly coupled in the delocalized confinement. Furthermore, we demonstrate simultaneous optical trapping of multiple JPs. This first report on thermophoresis of Pt-silica JPs and localized-to-delocalized crossover in the position distributions of an optically trapped active JP, verifying theoretical predictions, advances our understanding of confined active matter and their experimental realizations.

The development of silicon-compatible, high-performance infrared photodetectors is crucial for advancing thermal imaging, security, and communication systems. While germanium is a promising near-infrared material, its behavior in nanostructured forms with silicon heterojunctions reveals complex photophysics. This work demonstrates a germanium nanowire photodetector grown on a silicon-on-insulator (SOI) platform that exhibits a striking, tunable coexistence of both positive photoconductivity (PPC) and negative photoconductivity (NPC). We show that the dominant photoresponse can be switched by the wavelength of incident light: NPC dominates at visible wavelengths (e.g., 532 nm), while PPC prevails in the near-infrared (e.g., 1310 nm). Through systematic experiments and FDTD and TCAD simulations, we elucidate that this phenomenon arises from the interplay of light absorption in the different layers of the heterostructure. At short wavelengths, strong absorption in the underlying Si layer forward-biases the heterojunction, injecting carriers that quench the Ge channel conductance (NPC). At long wavelengths, absorption is confined to the Ge layer, resulting in conventional PPC. Negative photoconductivity was consistently observed over the temperature range from 78 to 298 K. Notably, the maximum responsivity of the nanowire increased from −56.7 A/W at room temperature to −1421.5 A/W at 78 K. This is attributed to the suppression of surface recombination velocity, increasing the minority carrier lifetime by 2 orders of magnitude. The −3 dB bandwidth is 2.9 kHz under 532 nm light and 3.9 kHz under 1310 nm light. The minimum noise equivalent power is determined to be 5.3 × 10–14 W/Hz0.5, corresponding to a specific detectivity of 4.0 × 109 Jones at room temperature. Furthermore, we demonstrate that the crossover wavelength is intensity-dependent and that the photocurrent follows an established logarithmic model for nanowire photoconductors. This work provides a controllable model system for studying NPC and presents a novel device architecture with tunable, multifunctional photoresponse for advanced optoelectronic applications.