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.

Ultraviolet Exciton-Polariton Light-Emitting Diode in a ZnO Microwire Homojunction.

Low-dimensional ZnO, possessing well-defined side facets and optical gain properties, has emerged as a promising material to develop ultraviolet coherent light sources. However, the realization of electrically driven ZnO homojunction luminescence and laser devices is still a challenge due to the absence of a reliable p-type ZnO. Herein, the sample of p-type ZnO microwires doped by Sb (ZnO:Sb MWs) was synthesized individually.

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.

Twisted graphene stabilized by organic linkers pillaring.

Twisted graphene, including magic angle graphene, has attracted extensive attentions for its novel properties recently. However, twisted graphene is intrinsically unstable and this will obstruct their application in practice, especially for twisted nano graphene. The twist angles between adjacent layers will change spontaneously.

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).

Evolution and Synthesis of Carbon Dots: From Carbon Dots to Carbonized Polymer Dots.

Despite the various synthesis methods to obtain carbon dots (CDs), the bottom-up methods are still the most widely administrated route to afford large-scale and low-cost synthesis. However, as CDs are developed with increasing reports involved in producing many CDs, the structure and property features have changed enormously compared with the first generation of CDs, raising classification concerns. To this end, a new classification of CDs, named carbonized polymer dots (CPDs), is summarized according to the analysis of structure and property features.

Efficient Red/Near-Infrared-Emissive Carbon Nanodots with Multiphoton Excited Upconversion Fluorescence.

Red/near-infrared (NIR) emissive carbon nanodots (CNDs) with photoluminescence (PL) quantum yield (QY) of 57% are prepared via an in situ solvent-free carbonization strategy for the first time. 1-Photon and 2-photon cellular imaging is demonstrated by using the CNDs as red/NIR fluorescence agent due to the high PL QY and low biotoxicity. Further study shows that the red/NIR CNDs exhibit multiphoton excited (MPE) upconversion fluorescence under excitation of 800-2000 nm, which involves three NIR windows (NIR-I, 650-950 nm; NIR-II, 1100-1350; NIR-III, 1600-1870 nm).

A series of blue-green-yellow-red emitting Cu(I) complexes: Molecular structure and photophysical performance.

In this work, we designed a series of [Cu(NN)(PPh)]BF complexes with different optical edge values and emission colors from blue to red, where NN and PPh denoted a diamine ligand and triphenylphosphine, respectively. Six NN ligands with various conjugation chains (short π chain, modest π chain and long π chain) were selected. A systematical comparison between these Cu(I) complexes was performed, so that the correlation between NN structure and [Cu(NN)(PPh)] photophysical performance was tentatively discussed.

Room-temperature continuous-wave electrically pumped InGaN/GaN quantum well blue laser diode directly grown on Si.

Current laser-based display and lighting applications are invariably using blue laser diodes (LDs) grown on free-standing GaN substrates, which are costly and smaller in size compared with other substrate materials. Utilizing less expensive and large-diameter Si substrates for hetero-epitaxial growth of indium gallium nitride/gallium nitride (InGaN/GaN) multiple quantum well (MQW) structure can substantially reduce the cost of blue LDs and boost their applications. To obtain a high crystalline quality crack-free GaN thin film on Si for the subsequent growth of a blue laser structure, a hand-shaking structure was formed by inserting Al-composition step down-graded AlN/AlGaN buffer layers between GaN and Si substrate.