On-chip near-infrared gas sensing based on slow light mode multiplexing in photonic crystal waveguides.

Photonic crystal slow light waveguides present a breakthrough in the manipulation of optical signals and enhancing the interaction between light and matter. In particular, two-dimensional (2D) photonic crystal waveguides (PCWs) on silicon photonic chips hold promise in improving the sensitivity of on-chip gas sensors. However, the development of the gas sensors based on 2D PCWs suffers from a high propagation loss and a narrow slow light bandwidth.

On-chip near-infrared multi-gas sensing using chalcogenide anti-resonant hollow-core waveguides.

On-chip infrared spectroscopic gas sensing using a hollow-core anti-resonant reflecting optical waveguide (ARROW) with a large external confinement factor (ECF) was rarely reported due to the complex fabrication process and polarization dependence. Alternatively, we proposed ARROW gas sensors using chalcogenide (ChG) anti-resonant layers which require thermal evaporation and epoxy resin bonding for fabrication instead of the complicated wafer bonding process. Polarization characteristics and ethylene (CH) sensing performance at 1.

Analysis of the Influence of the Dynamic Characteristics of an Optical Bench on Optical Mechanical System Imaging Under Vibration Conditions.

The imaging processes of optoelectronic devices are affected by vibration in the transportation platform, which can cause image shaking and blurring. Nowadays, devices often solve problems of image shaking and blurring using motion rotors. However, there is relatively little research on the influence of optical fixtures themselves under vibration conditions.

Dynamic Reconstruction of Fluid Interface Manipulated by Fluid Balancing Agent for Scalable Efficient Perovskite Solar Cells.

Laboratory-scale spin-coating techniques are widely employed for fabricating small-size, high-efficiency perovskite solar cells. However, achieving large-area, high-uniformity perovskite films and thus high-efficiency solar cell devices remain challenging due to the complex fluid dynamics and drying behaviors of perovskite precursor solutions during large-area fabrication processes. In this work, a high-quality, pinhole-free, large-area FAPbI perovskite film is successfully obtained via scalable blade-coating technology, assisted by a novel bidirectional Marangoni convection strategy.

Overcoming the EQE × Li-Fi Frequency Constraint by Modulating the PbS CQDs Distribution in Perovskite Film.

Advanced photodetectors are crucial for high-fidelity optical communication. However, the tradeoff between high external quantum efficiency (EQE) and high light fidelity (Li-Fi) frequency often limits data transmission accuracy and timeliness. Here, we report a photodetector consisting of lead sulfide (PbS) colloidal quantum dots (CQDs) with near-infrared responsiveness and perovskite frameworks responsible for the charge transport to overcome the EQE × Li-Fi constraint.

Enhanced Higher Harmonic Generation in Modified MAPbBrCl Single Crystal by Additive Engineering.

Mixed-halide perovskite materials (MHSCs) hold significant interest in photonics applications owing to their inherent advantages, including tunable bandgap properties, remarkable defect tolerance characteristics, and facile processability. These attributes position MHSCs as up-and-coming materials for various applications. However, the commercialization of these materials is severely affected by external factors, such as humidity and oxygen.

Ultra-Wideband Mid-Infrared Chalcogenide Suspended Nanorib Waveguide Gas Sensors with Exceptionally High External Confinement Factor beyond Free-Space.

On-chip waveguide sensors are potential candidates for deep-space exploration because of their high integration and low power consumption. Since the fundamental absorption of most gas molecules exists in the mid-infrared (e.g.

WMS-based near-infrared on-chip acetylene sensor using polymeric SU8 Archimedean spiral waveguide with Euler S-bend.

SU8 is a cost-effective polymer material that is highly suitable for large-scale fabrication of waveguides. However, it has not been employed for on-chip gas measurement utilizing infrared absorption spectroscopy. In this study, we propose a near-infrared on-chip acetylene (CH) sensor using SU8 polymer spiral waveguides for the first time to our knowledge.

Wafer-Level, High-Performance, Flexible Sensors Based on Organic Nanoforests for Human-Machine Interactions.

High-performance flexible sensors are essential for real-time information analysis and constructing noncontact communication modules for emerging human-machine interactions. In these applications, batch fabrication of sensors that exhibit high performance at the wafer level is in high demand. Here, we present organic nanoforest-based humidity sensor (NFHS) arrays on a 6 in.

Recent Progress in Double-Layer Honeycomb Structure: A New Type of Two-Dimensional Material.

Two-dimensional (2D) materials are no doubt the most widely studied nanomaterials in the past decade. Most recently, a new type of 2D material named the double-layer honeycomb (DLHC) structure opened a door to achieving a series of 2D materials from traditional semiconductors. However, as a newly developed material, there still lacks a timely understanding of its structure, property, applications, and underlying mechanisms.

On-chip mid-infrared silicon-on-insulator waveguide methane sensor using two measurement schemes at 3.291 μm.

Portable or even on-chip detection of methane (CH) is significant for environmental protection and production safety. However, optical sensing systems are usually based on discrete optical elements, which makes them unsuitable for the occasions with high portability requirement. In this work, we report on-chip silicon-on-insulator (SOI) waveguide CH sensors at 3.

Direct synthesis of Au-Ag nanoframes by galvanic replacement a continuous concaving process.

Controlled synthesis of noble-metal nanoframes is of great interest due to their promising applications in plasmonics and catalysis. However, the synthesis is largely limited to a multiple-step approach involving selective deposition followed by selective etching. Here we report a facile and general strategy to synthesize Au-Ag nanoframes based on a direct galvanic replacement reaction between Ag nanoparticles and a gold(I) complex, sodium aurothiosulfate, without an extra etching process.

MoS/LaF for enhanced photothermal therapy performance of poorly-differentiated hepatoma.

Photothermal therapy (PTT) based on nanoparticle had been widely used to antitumor treatment. However, low photothermal conversion efficiency (PCE) is the main hurdle for antitumor treatment. To improve the PCE and gain ideal clinical the nanoparticle with higher photothermal conversion efficiency, we have developed a highly efficient solar absorber with MoS/LaF/ polydimethylsiloxane(PDMS) which can enhance the absorption of solar irradiation engergy, however, its photothermal effect irradiated by near-infrared light has not yet been investigated.

Two Luminescent Iridium Complexes with Phosphorous Ligands and Their Photophysical Comparison in Solution, Solid and Electrospun Fibers: Decreased Aggregation-Caused Emission Quenching by Steric Hindrance.

In this paper, we prepared two phosphorescent Ir complexes with ligands of 2-phenyl pyridine (ppy), and two phosphorous ligands with large steric hindrance, hoping to allow enough time for the transformation of the highly phosphorescent MLLCT (metal-to-ligand-ligand-charge-transfer) excited state. Their large steric hindrance minimized the π-π interaction between complex molecules, so that the aggregation-induced phosphorescence emission (AIPE) influence could be minimized. Their single crystals indicated that they took a distorted octahedral coordination mode.

AlInGaAs Multiple Quantum Well-Integrated Device with Multifunction Light Emission/Detection and Electro-Optic Modulation in the Near-Infrared Range.

A monolithic photonic chip with multifunctional light emission/detection and electro-optic modulation capabilities in the near-infrared range is proposed and realized on an InP-based wafer. Two identical AlInGaAs multiple quantum well (MQW) diodes operating independently as light emission/detection devices are fabricated using a two-step etching process on a single wafer and connected via a straight waveguide. The photocurrent induced in the MQW diode for the detection process is generated by the infrared light emitted by the MQW diode during the emission process and transmitted via the straight waveguide.

Low-Temperature-Induced Controllable Transversal Shell Growth of NaLnF Nanocrystals.

Highly controllable anisotropic shell growth is essential for further engineering the function and properties of lanthanide-doped luminescence nanocrystals, especially in some of the advanced applications such as multi-mode bioimaging, security coding and three-dimensional (3D) display. However, the understanding of the transversal shell growth mechanism is still limited today, because the shell growth direction is impacted by multiple complex factors, such as the anisotropy of surface ligand-binding energy, anisotropic core-shell lattice mismatch, the size of cores and varied shell crystalline stability. Herein, we report a highly controlled transversal shell growth method for hexagonal sodium rare-earth tetrafluoride (β-NaLnF) nanocrystals.

Development of Halide Perovskite Single Crystal for Radiation Detection Applications.

Recently, low-cost perovskite single crystals have attracted intensive attention due to their excellent optoelectronic properties and improved stability when compared to polycrystalline films for various applications, such as solar cells (Kojima et al., 2009; Lee et al., 2012; Tsai et al.

Facile Strategy for Facet Competition Management to Improve the Performance of Perovskite Single-Crystal X-ray Detectors.

Methylammonium lead tribromide perovskite single crystals have been demonstrated to be good candidates as sensitive X-ray detectors in direct detection mode in recent years. However, its X-ray detection performance based on the orientation of different facets is still not clear. Here, we developed a facile strategy to chemically expose the [110] facet of single crystals from low-cost solution processes by tailoring the nonstoichiometry of feeding ions to selectively suppress the growth of the [100] facet.

Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation.

Phonon polaritons-light coupled to lattice vibrations-in polar van der Waals crystals are promising candidates for controlling the flow of energy on the nanoscale due to their strong field confinement, anisotropic propagation and ultra-long lifetime in the picosecond range. However, the lack of tunability of their narrow and material-specific spectral range-the Reststrahlen band-severely limits their technological implementation. Here, we demonstrate that intercalation of Na atoms in the van der Waals semiconductor α-VO enables a broad spectral shift of Reststrahlen bands, and that the phonon polaritons excited show ultra-low losses (lifetime of 4 ± 1 ps), similar to phonon polaritons in a non-intercalated crystal (lifetime of 6 ± 1 ps).