All-inorganic perovskite micro/nanowire materials hold great promises as nanoscale coherent light source due to their superior optical and electronic properties. The coupling strength between exciton and photon in this system is important for their optical application, however, is rarely studied. In this work, we demonstrated the strong coupling of exciton-photon and polariton lasing in high quality CsPbBr3 micro/nanowires synthesized by a CVD method. By exploring spatial resolved PL spectra of CsPbBr3 cavity, we observed mode volume dependent coupling strength with a vacuum Rabi splitting up to 656 meV, as well as significant increase in group index. Moreover, low threshold polariton lasing was achieved at room temperature within strong coupling regime; the polariton characteristic is confirmed by comparing lasing spectra with waveguided output spectra and the dramatically reduced lasing threshold. Our present results provide new avenues to achieve high coupling strengths potentially enabling application of exciting phenomena such as Bose-Einstein condensation of polaritons, efficient light-emitting diodes and lasers.

Manipulating strong light-matter interaction in semiconductor microcavities is crucial for developing high-performance exciton polariton devices with great potential in next-generation all-solid state quantum technologies. In this work, we report surface plasmon enhanced strong exciton-photon interaction in CHNHPbBr perovskite nanowires. Characteristic anticrossing behaviors, indicating a Rabi splitting energy up to ∼564 meV, are observed near exciton resonance in hybrid perovskite nanowire/SiO/Ag cavity at room temperature. The exciton-photon coupling strength is enhanced by ∼35% on average, which is mainly attributed to surface plasmon induced localized excitation field redistribution. Further, systematic studies on SiO thickness and nanowire dimension dependence of exciton-photon interaction are presented. These results provide new avenues to achieve extremely high coupling strengths and push forward the development of electrically pumped and ultralow threshold small lasers.

Lead halide perovskites have emerged as excellent optical gain materials for solution-processable and flexible lasers. Recently, continuous-wave (CW) optically driven lasing was established in perovskite crystals; however, the mechanism of low-threshold operation is still disputed. In this study, CW-pumped lasing from one-dimensional CsPbBr3 nanoribbons (NBs) with a threshold of ∼130 W cm–2 is demonstrated, which can be ascribed to the large refractive index induced by the exciton–polariton (EP) effect. Increasing the temperature reduces the exciton fraction of EPs, which decreases the group and phase refractive indices and inhibits lasing above 100 K. Thermal management, including reducing the NB height to ∼120 ± 60 nm and adopting a high-thermal-conductivity sink, e.g., sapphire, is critical for CW-driven lasing, even at cryogenic temperatures. These results reveal the nature of ultralow-threshold lasing with CsPbBr3 and provide insights into the construction of room-temperature CW and electrically driven perovskite macro/microlasers.

2D metallic TaS is acting as an ideal platform for exploring fundamental physical issues (superconductivity, charge-density wave, etc.) and for engineering novel applications in energy-related fields. The batch synthesis of high-quality TaS nanosheets with a specific phase is crucial for such issues. Herein, the successful synthesis of novel vertically oriented 1T-TaS nanosheets on nanoporous gold substrates is reported, via a facile chemical vapor deposition route. By virtue of the abundant edge sites and excellent electrical transport property, such vertical 1T-TaS is employed as high-efficiency electrocatalysts in the hydrogen evolution reaction, featured with rather low Tafel slopes ≈67-82 mV dec and an ultrahigh exchange current density ≈67.61 µA cm . The influence of phase states of 1T- and 2H-TaS on the catalytic activity is also discussed with the combination of density functional theory calculations. This work hereby provides fundamental insights into the controllable syntheses and electrocatalytic applications of vertical 1T-TaS nanosheets achieved through the substrate engineering.

Miniaturized laser is the key element for integrated on-chip photonic device. Semiconductor materials are excellent candidates for gain medium of microscale laser, especially for nanowire (NW) based lasers. However, optical diffraction law constrains the footprint of photonic NW based device with the scale of half wavelength. [1] While in hybrid metal-semiconductor plasmonic nanostructures, photon energy could be coupled into collective electron oscillations in the form of surface plasmon polaritons (SPPs) at a metal-dielectric interface, [2][3][4] which therefore provide an effective solution to overcome optical diffraction limit. Similar to photonic laser, plasmonic lasers get amplification of SPPs by energy transfer from nonradiative part excitons of semiconductor material, where semiconductor severs as the gain media driving the inversion of SPP population at the metal-dielectric interface. [5][6][7] The SPP lasers show superior capabilities in strong light-matter interaction, which have potential applications in integrated photonics, biosensors, and quantum information technologies. [8][9][10] A series of inorganic II-VI and III-V compound semiconductor plasmonic NW lasers have been achieved in GaN, ZnO, and CdS NWs [11][12][13][14][15] at room temperature, because these NWs gain medium produce sufficient gain to overcome the high losses in metals. The fabrication procedures usually require extreme conditions such as high-temperature or low-pressure conditions, leading to high cost. However, till now the thresholds of the resulting lasers are still high, low-cost gain materials with excellent gain characteristics are in urgent need to be exploited to overcome these problems.Recently, organic-inorganic lead halide perovskites (CH 3 NH 3 PbX 3 , X = Cl, Br, I) have attracted intensive attentions for their huge potential in photovoltaics, with a power conversion efficiency exceeded 22.1% in solar cells. [16] On the other hand, lead halide perovskites have emerged as promising optical gain materials for achieving low-threshold plasmonic lasers owing to their excellent optical properties in a wide spectrum range, such as large absorption coefficients, high photoluminescence (PL) quantum yield, and low nonradiative recombination rates. [17][18][19][20][21] In past few years, SPP lasers have been investigated in hybrid perovskites. For instance, Kao et al. demonstrated enhanced localized surface plasmonic lasing performance in solution-processed CH 3 NH 3 PbI 3 perovskite films in Plasmonic nanolaser holds great potential in breaking down the diffraction limit of conventional optics to the deep sub-wavelength regime and in ultrafast lasing dynamics. However, plasmonic laser devices are constrained in practical applications due to their high cost and high thresholds. All-inorganic cesium lead halide perovskites are promising solutions for their excellent optical gain properties and high emission efficiency. In this work, high-quality single-crystalline CsPbBr 3 perovskite nanowires (NWs) are synthesized by chemical ...

2D metallic transition metal dichalcogenides (MTMDCs) are benchmark systems for uncovering the dimensionality effect on fascinating quantum physics, such as charge-density-wave (CDW) order, unconventional superconductivity, and magnetism, etc. However, the scalable and thickness-tunable syntheses of such envisioned MTMDCs are still challenging. Meanwhile, the origin of CDW order at the 2D limit is controversial. Herein, the direct synthesis of wafer-scale uniform monolayer 2H-TaSe 2 films and thickness-tunable flakes on Au foils by chemical vapor deposition is accomplished. Based on the thickness-tunable 2H-TaSe 2 , the robust periodic lattice distortions that relate to CDW orders by low-temperature transmission electron microscopy are directly visualized. Particularly, a phase diagram of the transition temperature from normal metallic to CDW phases with thickness by variable-temperature Raman characterizations is established. Intriguingly, dramatically enhanced transition temperature from bulk value ≈90 to ≈125 K is observed from monolayer 2H-TaSe 2 , which can be explained by the enhanced electron-phonon coupling mechanism. More importantly, an ultrahigh specific capacitance is also obtained for the as-grown TaSe 2 on carbon cloth as supercapacitor electrodes. The results hereby open up novel avenues toward the large-scale preparation of high-quality MTMDCs, and shed light on their applications in exploring some fundamental issues.

The incidence of giant cell tumor in the Chinese population may be higher than that in Western countries, and it has a male predilection. The results of the present study suggest that extensive curettage provides favorable local control and satisfactory functional outcomes.

The mechanism of single-mode lasing in CsPbBr3 microsphere shifts from exciton–exciton scattering to exciton–phonon scattering with the increase in temperature from 77 to 300 K, and two different phonon modes were involved in the exciton–phonon scattering process.