Black phosphorus (BP), a burgeoning elemental 2D semiconductor, has aroused increasing scientific and technological interest, especially as a channel material in field-effect transistors (FETs). However, the intrinsic instability of BP causes practical concern and the transistor performance must also be improved. Here, the use of metal-ion modification to enhance both the stability and transistor performance of BP sheets is described. Ag spontaneously adsorbed on the BP surface via cation-π interactions passivates the lone-pair electrons of P thereby rendering BP more stable in air. Consequently, the Ag -modified BP FET shows greatly enhanced hole mobility from 796 to 1666 cm V s and ON/OFF ratio from 5.9 × 10 to 2.6 × 10 . The mechanisms pertaining to the enhanced stability and transistor performance are discussed and the strategy can be extended to other metal ions such as Fe , Mg , and Hg . Such stable and high-performance BP transistors are crucial to electronic and optoelectronic devices. The stability and semiconducting properties of BP sheets can be enhanced tremendously by this novel strategy.

Two-dimensional (2D) black phosphorus (BP) shows thickness dependent direct energy band-gaps in association with strong light-matter interaction and broadband optical response, rendering it with promising optoelectronic advantages particularly at the telecommunication band. However, intrinsic BP suffers from irreversible oxidization, restricting its competences toward real device applications. As one potential of 2D materials, all-optical signal processing sensitively depends on the strength of light−matter interaction. BP can be utilized as a novel optical medium. Herein, fewlayer BP is synthesized with metal-ion-modification against oxidation and degradation, and then the feasibility of BP-coated microfiber as an optical Kerr switcher and a four-wave-mixing-based wavelength converter is demonstrated. The wavelength-tuning, long-term stability, wide-band RF frequency, and time-repeating measurements confirm that this optical device can operate as a broadband all-optical processor. It is further anticipated that metal-ion-modified BP might provide a new effective option for photonic applications toward high performances and enhanced stability.

2D titanium disulfide (TiS2) is recently found to have strong light absorption properties from visible to infrared (IR) region. This feature is highly attractive for applications in nonlinear photonics; however, the mechanism of broadband light–matter interaction is yet to be determined and nonlinear photonic devices are not developed. Here, for the first time, the experimental evidence supporting the mechanism of the broadband nonlinear photoresponse in ultrathin TiS2 nanosheets ranging from 400 nm to 1390 nm is reported through laser Z‐scan measurements. High‐performance nonlinear photonic devices operating in the telecommunication band are also demonstrated. A novel saturable absorber (SA) device is successfully fabricated based on a 2D TiS2‐decorated fiber, which exhibits outstanding ultrashort pulse generation performance with pulse duration of ≈1.04 ps centered at 1569.5 nm. Furthermore, as a stable all‐optical thresholding component, the device can effectively attenuate noise and boost the signal‐to‐noise ratio of the pulse from 1.90 to 10.68 dB. The findings indicate that TiS2‐based SA devices can be developed into excellent highly nonlinear photonic devices, which may advance the development of TiS2‐based optical communication technologies in the future.

As a novel semiconducting materials, BP-QDs possess superior transfection efficiency, excellent biocompatibility and low cytotoxicity, which shows promising potential for siRNA delivery and photothermal effects in cancer therapy.

We report on the optical saturable absorption of few-layer black phosphorus nanoflakes and demonstrate its application for the generation of vector solitons in an erbium-doped fiber laser. By incorporating the black phosphorus nanoflakes-based saturable absorber (SA) into an all-fiber erbium-doped fiber laser cavity, we are able to obtain passive mode-locking operation with soliton pulses down to ~670 fs. The properties and dynamics of the as-generated vector solitons are experimentally investigated. Our results show that BP nanoflakes could be developed as an effective SA for ultrashort pulse fiber lasers, particularly for the generation of vector soliton pulses in fiber lasers.

As a new class of 2D materials, MXenes have attracted a lot of interest because of their prominent performance in versatile applications, such as batteries, supercapacitors, catalysts, electronics, and optics. In this work, an all‐optical modulator using MXene Ti3C2Tx deposited on a microfiber is proposed. By inserting an MXene‐deposited phase shifter into one arm of a Mach–Zehnder interferometer, the MXene Ti3C2Tx absorbs the control light and generates heat, which induces significant refractive index changes through strong light–matter interactions and thermo‐optic effects. In this study, a maximum phase shift of 16π is obtained, and an efficient all‐optical switch with an extinction ratio of more than 18.53 dB and a rise time constant of 4.10 ms are demonstrated. The advantages of this modulator include its all‐fiber content, low cost, ease of integration, and compactness. All‐optical modulators based on thermo‐optical effects will play an active role in the future of optical communications and optical information processing.

The stabilization of black phosphorous quantum dots (BPQDs) for optical application under ambient conditions is highly challenging. Here, a facile approach is presented to substantially stabilize BPQDs by making a uniform BPQDs/polymethyl methacrylate (PMMA) composite nanofiber film via an electrospinning technique. As verified by femtosecond laser Z-scan measurement, the BPQDs/PMMA composite nanofiber film that has been stored for three months exhibits almost the same nonlinear optical properties as the fresh BPQDs. Additionally, the BPQDs/PMMA composite nanofiber film demonstrates broadband nonlinear optical response ranging from the visible bandwidth (400 nm) to the mid-IR bandwidth (at least 1930 nm). By employing the BPQDs/PMMA composite nanofiber film as an optical saturable absorber, an ultrashort pulse with the pulse duration of ≈1.07 ps centered at the wavelength of 1567.6 nm is generated in a mode-locked fiber laser. These results suggest that the BPQDs/PMMA composite nanofiber film can combine the advantage of convenient integration and mitigation of the drawback of the easy oxidation of black phosphorous and pave the way for BP-based practical optoelectronic devices.owing to their unique optical properties such as broadband absorption, low saturation ultrashort recovery time, and tunable optical modulation depth. [2][3][4][5][6][7][8][9][10] The research on 2D materials strongly contributes to the development of laser technology in the generation of shorter purses and broader bandwidths in new wavelength regions that are impossible to achieve with conventional technology. However, the applications of these 2D materials are limited because of their intrinsic energy band gaps. [11][12][13] Since 2014, black phosphorous (BP) as an emerging graphene-like layered material has shown high hole mobility and has been widely used in optoelectronic devices. [14][15][16][17][18] BP has a layer-dependent direct band gap structure, with the band gap ranging from 0.3 eV (bulk) to 1.5 eV (monolayer), exactly bridging the gap between its 2D counterparts: graphene (zero band gap) and TMDs (relatively wide band gaps: 1.5-2.5 eV). [19][20][21] Mechanical, liquid exfoliation, and solvothermal methods have been employed to prepare BP nanosheets [22][23][24] that exhibit attractive broadband saturable absorption properties in a wide spectral range from the visible to mid-infrared and the ultrashort recovery time property of several tens femtosecond ultrafast dynamic delay time [25][26][27] and are used as a superior SA of Q-switching or mode-locking to generate ultrafast laser pulses.

The synthesized FL Se-doped compound shows enhanced optical saturable absorption and high electrical characterizations, which can be developed as an excellent candidate for photoelectric devices.