Emerging High-Performance SnS/CdS Nanoflower Heterojunction for Ultrafast Photonics

Heterojunctions Based on 2D Materials for Pulse Laser Applications

In recent years, heterostructures composed of two-dimensional (2D) materials have demonstrated broad application prospects across various domains, primarily attributed to their exceptional electrical and optical properties. The superior performance of these heterostructures is rooted in the interlayer interactions and the diversity of the constituent materials. Notably, their applications have been greatly advanced in optical fields such as photodetectors, lasers, modulators, optical sensors, and nonlinear optics. etc. This review delineates the advancement of heterostructures based on 2D materials and discusses the electronic structural properties of their interfaces and band alignments while summarizing their carrier dynamics and nonlinear optical characteristics. Furthermore, it explores the synthesis techniques of 2D heterostructures and their applications as saturable absorbers in laser Q-switching and mode-locking, emphasizing the critical role that type-I and type-II heterojunctions have played in advancing laser technology. Lastly, the challenges and future opportunities in the application of 2D heterostructures in laser technologies are reviewed, offering insights on the potential directions for further research in this field.

An Environmental Engineering Study Case: Constructing Cataluminescence Sensors Based on Octahedral Nanocomposites for Isovaleraldehyde Detection

Isovaleraldehyde is an important chemical raw material for the production of flavors, which is volatile and flammable and poses a health risk to humans. It is, therefore, essential to develop a rapid assay for the identification of isovaleraldehyde. In this study, octahedral NiCo2O4/MIL-Fe53 nanocomposites were successfully fabricated for the rapid detection of isovaleraldehyde. The prepared NiCo2O4/MIL-Fe53 nanocomposites were characterized by SEM, XRD, FTIR, and XPS to analyze the material properties. The effects of temperature, carrier gas flow rate, selectivity, and stability on the cataluminescence performance of this sensor were investigated. The results showed that NiCo2O4/MIL-Fe53 nanocomposites have excellent selectivity to isovaleraldehyde with response and recovery times of 6 and 8 s, respectively. A linear relationship was found between the CTL signal and isovaleraldehyde concentration Y = 9.56X - 23.3 (R2 = 0.99) over the concentration range of 13.66 to 437.22 ppm with a detection limit of 2.44 ppm. The relative deviation RSD = 4.18% for multiple tests of the sensor indicates good stability and longevity. Mechanistic studies have shown that the heterojunction formed by NiCo2O4/MIL-Fe53 nanocomposites has the advantage of improving CTL sensing performance. This study may advance the application of cataluminescence sensors in the detection of isovaleraldehyde.

Surface Plasmon Resonance-Enhanced CdS/FTO Heterojunction for Cu2+ Detection

Copper ion (Cu2+) pollution poses a serious threat to marine ecology and fisheries. However, the complexity of seawater and its interference factors make the online detection of Cu2+ quite challenging. To address this issue, we introduce the concept of the photo-assisted adjustment barrier effect into electrochemical detection, using it as a driving force to generate electrochemical responses. The Schottky barrier demonstrates a remarkable regulatory influence on the electrochemical response under photoexcitation, facilitating the response through Cu2+ adsorption. We developed a 4-MBA-AuNPs/CdS/FTO composite that serves as a sensitive platform for Cu2+ detection, achieving a detection limit of 70 nM. Notably, the photo-assisted adjustment of the barrier effect effectively counters the interference posed by ions in seawater, ensuring accurate detection. Furthermore, the sensor exhibits a promising recovery rate (99.62-104.9%) in real seawater samples, highlighting its practical applications. This innovative approach utilizing the photo-assisted adjustment barrier effect offers a promising path for developing electrochemical sensors that can withstand interference.

Synthesis of CuO/polyaniline/multiwalled carbon nanotube composites using Macaranga indica leaves extract as hydrogen gas sensor

In this study, we describe the fabrication of hydrogen gas sensors in the form of nanocomposites containing metal oxides such as copper oxide (CuO), multiwalled carbon nanotubes (MWCNTs), and polyaniline (PANI) using a green synthesis method. We used Macaranga indica (M. indica) leaf extract as a reducing and stabilizing agent to prepare copper oxide nanoparticles (CuONPs). The sample was analyzed using various techniques to determine its physicochemical, morphological, and elemental composition. The XRD data showed that the sample is a CuO/PANI/MWCNT nanocomposite by the best match with the reported data. SEM images revealed a uniform distribution of MWCNTs and spherical CuO nanoparticles of 30-40 nm throughout the CNT network. EDX confirmed that the prepared sample is a pure and inline combination of Cu, O, C, and N. Due to the presence of bioactive elements and PANI, we observed 17% and 25% weight loss for CuO and CuO/PANI/MWCNTs. It was found that this combination of materials can detect H2 gas in concentrations ranging from 110 to 2 ppm at temperatures of 200 and 250 °C. As H2 concentration increased, sensitivity varied from 5% to 20%, but response and recovery times were about 290 and 500 s, respectively, for 40 ppm H2 gas. A logistic function fit to Ra/Rg versus H2 was performed using Y = A2 + (A1 - A2)/(1 + (x/x0)p). The energy bands among the CuO/PANI/MWCNT heterointerfaces were used to demonstrate enhanced H2 gas-sensing properties.

A Strategy for Studying Environmental Engineering: Simple Hydrothermal Synthesis of Flower-Shaped Stannous Sulfide Nanomaterials for Efficient Cataluminescence Sensing of Diethyl Ether

In this work, flower-like stannous sulfide (SnS) nanomaterials are synthesized using a hydrothermal method and used as sensitive materials for cataluminescence (CTL)-based detection of diethyl ether. Gas sensors based on SnS nanomaterials are prepared, and the SnS nanomaterials exhibit excellent gas-sensitive behavior towards ether. High sensitivity to ether is achieved at a relatively low operating temperature (153 °C) compared to other common sensors. The response time is 3 s and the recovery time is 8 s. The CTL intensity shows a good linear relationship (R2 = 0.9931) with a detection limit of 0.15 ppm and the concentration of ether in the range of 1.5-60 ppm. The proposed CTL sensor shows good selectivity towards ether. In addition, a highly stable signal is obtained with a relative standard deviation of 1.5%. This study indicates that the SnS-based sensor has excellent gas-sensitive performance and shows potential for applications in the detection of ether.

Transparent nanopaper for ultrashort pulse generation in the near-infrared region

Transparent nanopaper (T-paper) can be applied in the field of electromagnetic shielding materials, antistatic materials, composite conductive materials, electric pool materials, super capacitors, and thermal management systems. However, this kind of T-paper has not been employed in ultrafast photonics yet. For the first time, to our knowledge, transparent electrical nanopaper is used in fiber lasers, different from the conventional pulsed fiber laser, which operates in the Q-switched regime under low pump power and then in the mode-locked regime under high pump power. Mode-locking is achieved first with a pulse duration of 550 fs under low pump power (166 mW). When further increasing the pump power up to 198 mW, the proposed fiber laser can be converted from a mode-locked to Q-switched state, which is a result of the two-photon absorption effect. The proposed fiber laser based on T-paper can be potentially applied in optical tomography, metrology, spectroscopy, micro-machining technology, and biomedical diagnostics.

Preparation of a novel Bi9O7.5S6/SnS composite film with improved photoelectric properties

Atomically thin two-dimensional (2D) bismuth oxychalcogenides have been considered as promising candidates for high-speed and low-power photoelectronic devices due to their high charge carrier mobility and excellent environmental stability. However, the photoelectric performance of their bulk materials still falls short of expectations. Herein, a novel Bi9O7.5S6/SnS composite film with a type-II heterojunction was successfully prepared by combining hydrothermal and knife-coating techniques. The crystal structure, morphology, and optical properties were systematically investigated. Under 1 V bias voltage, the photocurrent of the Bi9O7.5S6/SnS composite film can be obtained as 107 μA cm-2, which is about 29.9 times and 93.9 times higher than that of bare Bi9O7.5S6 and SnS, respectively. The type-II heterojunction has played a significant role in improving the photoelectric performance of the Bi9O7.5S6/SnS composite film by facilitating the separation and transfer of photo-generated carriers. This work sheds light on the design and development of new bismuth-based composite materials for advanced photoelectric and photocatalytic applications.

Ultrafast Hole Migration at the p-n Heterojunction of One-Dimensional SnS Nanorods and Zero-Dimensional CdS Quantum Dots

The p-n heterojunctions fabricated from one-dimensional (1D) p-type tin sulfide nanorods (SnS NRs) decorated with n-type zero-dimensional (0D) cadmium sulfide quantum dots (CdS QDs) have gained significant research attention in energy storage devices. Herein, we have successfully synthesized a 1D/0D SnS@CdS heterostructure (HS) using a hot injection method. Structural and morphological studies clearly suggest that CdS QDs are uniformly anchored on the surface of SnS NRs, resulting in intimate contact between two components. The photoluminescence (PL) study revealed the transfer of photoexcited holes from CdS QDs to SnS NRs, which was further confirmed by transient absorption (TA) studies. TA measurements demonstrate the hole transfer from the valence band of CdS QDs to SnS NRs and delocalization of electrons between the conduction band of SnS NRs and CdS QDs in SnS@CdS HS, resulting in efficient charge separation across the p-n heterojunction. These findings will open up a new paradigm for improving the efficiency of optoelectronic devices.

Super-gain nanostructure with self-assembled well-wire complex energy-band engineering for high performance of tunable laser diodes

Although traditional quantum-confined nanostructures e.g. regular quantum wells or quantum dots have achieved huge success in the field of semiconductor lasers for past decades, these traditional nanostructures are encountering the difficulty of enhancing device performance to a higher level due to their inherent gain bottleneck. In this paper, we are proposing a new super-gain nanostructure based on self-assembled well-wire complex energy-band engineering with InGaAs-based materials to break through the existing bottleneck. The nanostructure is constructed by utilizing the special strain-driven indium (In)-segregation and the growth orientation-dependent on-GaAs multi-atomic step effects to achieve the distinguished ultra-wide and uniform super-gain spectra. The structural details and its luminescence mechanism are investigated by multiple measurement means and theoretical modeling. The polarized gain spectra with the max fluctuation of <3 cm-1 in 904 nm-998 nm for transverse electric (TE) mode and 904 nm-977 nm for transverse magnetic (TM) mode are simultaneously obtained with this nanostructure. It enables an ultra-low output power fluctuation of <0.7 dB and a nearly-constant threshold power throughout an ultra-wide wavelength range under a fixed injection level. It was difficult to realize these in the past. Therefore, the described super-gain nanostructure brings a brand-new chance of developing high performance of tunable laser diodes.

Simulation of Laser-Heating and Energetic Plasma Plume Expansion in Pulsed Laser Deposition of Y3Fe5O12

In the present study, numerically iterative models are employed to study two processes involved in the pulsed laser deposition of an Y₃Fe₅O₁₂ target. The 1D conduction heat model is used to evaluate the temperature of the target irradiated by a nano-second pulse laser, taking into account the plasma shielding effect. Further, the gas dynamics model is employed to simulate the kinetic of plasma plume expansion. The results may be important in obtaining high-quality Y₃Fe₅O₁₂ thin films.

Plasmonic Near-Infrared Photoconductor Based on Hot Hole Collection in the Metal-Semiconductor-Metal Junction

Harvesting energetic carriers from plasmonic resonance has been a hot topic in the field of photodetection in the last decade. By interfacing a plasmonic metal with a semiconductor, the photoelectric conversion mechanism, based on hot carrier emission, is capable of overcoming the band gap limitation imposed by the band-to-band transition of the semiconductor. To date, most of the existing studies focus on plasmonic structural engineering in a single metal-semiconductor (MS) junction system and their responsivities are still quite low in comparison to conventional semiconductor, material-based photodetection platforms. Herein, we propose a new architecture of metal-semiconductor-metal (MSM) junctions on a silicon platform to achieve efficient hot hole collection at infrared wavelengths with a photoconductance gain mechanism. The coplanar interdigitated MSM electrode's configuration forms a back-to-back Schottky diode and acts simultaneously as the plasmonic absorber/emitter, relying on the hot-spots enriched on the random Au/Si nanoholes structure. The hot hole-mediated photoelectric response was extended far beyond the cut-off wavelength of the silicon. The proposed MSM device with an interdigitated electrode design yields a very high photoconductive gain, leading to a photocurrent responsivity up to several A/W, which is found to be at least 1000 times higher than that of the existing hot carrier based photodetection strategies.

Two-Dimensional Black Phosphorus: Preparation, Passivation and Lithium-Ion Battery Applications

As a new type of single element direct-bandgap semiconductor, black phosphorus (BP) shows many excellent characteristics due to its unique two-dimensional (2D) structure, which has great potential in the fields of optoelectronics, biology, sensing, information, and so on. In recent years, a series of physical and chemical methods have been developed to modify the surface of 2D BP to inhibit its contact with water and oxygen and improve the stability and physical properties of 2D BP. By doping and coating other materials, the stability of BP applied in the anode of a lithium-ion battery was improved. In this work, the preparation, passivation, and lithium-ion battery applications of two-dimensional black phosphorus are summarized and reviewed. Firstly, a variety of BP preparation methods are summarized. Secondly, starting from the environmental instability of BP, different passivation technologies are compared. Thirdly, the applications of BP in energy storage are introduced, especially the application of BP-based materials in lithium-ion batteries. Finally, based on preparation, surface functionalization, and lithium-ion battery of 2D BP, the current research status and possible future development direction are put forward.

Recycled Bifunctional Heterostructure Material: g-GaN/SnS for Photocatalytic Decomposition of Water and Efficient Detection of NO2

Recently, the energy crisis and environmental pollution problems have become increasingly severe. There is an urgent need to develop a class of multifunctional materials that can both produce clean energy and detect harmful gases. Herein, we propose a g-GaN/SnS heterostructure and explored its dual-optimal performance in photocatalytic hydrogen production and gas detection. Our results demonstrated that the g-GaN/SnS heterostructure has a suitable type II band alignment and excellent absorption in the visible range, which both indicate its potential application in photocatalysis. Furthermore, when the g-GaN/SnS heterostructure acted as a gas detection material, it was consistently susceptible to NO₂ gas molecules, according to charge transfer. Additionally, it has a very suitable material recovery time (∼0.5 h) when used for NO₂ detection, illustrating the recyclability of the material. Interestingly, the applied electric field of -0.4 V/Å can greatly increase the absorption coefficient in the visible range to 150% of the original. Also, the applied electric field of 0.6 V/Å can substantially enhance the gas detection sensitivity by 27% compared to the case without the electric field. Thus, the g-GaN/SnS heterostructure we proposed not only has the advantage of being bifunctional but also has the potential to be recycled.

All Optical Stabilizations of Nano-Structure-Based QDash Semiconductor Mode-Locked Lasers Based on Asymmetric Dual-Loop Optical Feedback Configurations

We report feedback-induced frequency oscillations using a power-split-ratio through asymmetric dual-loop optical feedback (Loop I: ~2.2 km and Loop II: ~20 m) subject to a self-mode-locked two-section QDash laser emitting at 1550 nm and operating at 21 GHz repetition rate. To assess the suppression of frequency resonances, three chosen combinations of feedback power (Loop I: −27.27 dB and Loop II: −19.74 dB, Loop I: −22 dB and Loop II: −22 dB, and Loop I: −19.74 dB and Loop II: −27.27 dB) through asymmetric dual-loop optical feedback have been studied. Based on the chosen coupling strength, an optimum feedback ratio that yields better side-mode suppression has been identified. Our results demonstrate that side-mode suppression can be achieved by the fine adjustment of coupling power through either cavity of dual-loop feedback configurations. Furthermore, we have further demonstrated that frequency fluctuations from the RF spectra can be filtered by carefully selecting the delay phase of the second cavity. Our experimental findings suggest that semiconductor mode-locked lasers based on dual-loop feedback configurations can be used to develop noise oscillations free from integrated photonic oscillators for potential applications in telecommunications, multiplexing, and frequency-comb generation.

Generation of bright-dark soliton pairs based on a ferromagnetic insulator Cr2Si2Te6 as a modulator in an Er-doped fiber laser

In this work, a saturable absorber (SA) based on Cr₂Si₂Te₆ (CST), with a modulation depth of 14.90% and saturation intensity of 4.81MW/cm², was prepared by a liquid phase stripping method. Its nonlinear optical properties and application in obtaining mode-locked pulse output of bright-dark solitons are studied. When the pump power was 1250 mW, the maximum output power was 26.60 mW; the energy of the single pulse was 15.02 nJ, and the repetition rate was 1.77 MHz. Our results provided evidence that CST can be used as an excellent SA for a mode-locked laser and demonstrated that ferromagnetic insulators can be used for the study of bright-dark soliton pairs.

Fabrication and enhanced photoelectric properties of a novel Bi9O7.5S6/CdS composite film

A novel Bi9O7.5S6/CdS composite film with a type-II heterojunction was presented with a superior photoelectric response and photostability under visible-light irradiation.

Investigation of photoelectric behaviors of silver sulfide particles in different surroundings

Silver sulfide (Ag2S) is a traditional semiconductor material, however, the photoelectric properties of Ag2S particles under different environments are still lacking. In this paper, we reported the preparation of Ag2S particles and their photoelectric properties under different environments. Results showed that the photoelectric performance of Ag2S particles was closely related to the environment. It was found that a copper phthalocyanine coating could improve the light response, the mixture of alcohols and air could increase the photoconductivity, and the mixture of carbon disulfide and air could decrease the photoconductivity. The mechanism of the effect of various experimental conditions on photoelectric properties was also discussed.

CdS@CdSe Core/Shell Quantum Dots for Highly Improved Self-Powered Photodetection Performance

Uniform, well-defined cadmium sulfide@cadmium selenide core/shell quantum dots (CdS@CdSe QDs) were, for the first time, successfully synthesized by a solvothermal method and chemical bath growth for photoelectrochemical activities. The as-synthesized CdS@CdSe QDs not only exhibit superior self-powered photoresponse behavior and excellent stability under ambient conditions but also display significantly improved current densities and photoresponsivity compared to those of individual CdS QDs or CdSe QDs, mainly due to the built-in electric field, and thus have great potential in the fields of renewable energy and renewable energy consumption for carbon neutrality target achievement.

Femtosecond ultrafast pulse generation with high-quality 2H-TaS2 nanosheets via top-down empirical approach

Tantalum disulfide (TaS₂), an emerging group VB transition metal dichalcogenide, with unique layered structure, rich phase diagrams, metallic behavior, higher carrier concentration and mobility is emerging as a prototype for revealing basic physical phenomena and developing practical applications. However, its photonics properties and even engineering-related processes are still rare. Here, the top-down experiment demonstration, including synthesis, thickness optimization and nonlinear optical application, has been reported. In addition, the ultrafast (∼373 fs) erbium-doped fiber pulse with a small time-bandwidth product (∼0.34) and long-term stability (∼25 days) was realized using the nonlinear absorption properties of the high-quality 2H-TaS₂ nanosheet. These results suggest an experimental route for further ultrafast photonics exploration based on metallic transition metal dichalcogenides.

Mercury ion-engineering Au plasmonics on MoS2 layers for absorption-shifted optical sensors

Semiconducting MoS₂ layers offer the electrons, reducing conjugated Au(I) to Au atoms, and sebsequently serve as desirable substrates for supporting the interfacial growths of gold nanostructures. Au-covering MoS₂ heterostructures perform morphology-varied optical characteristics, and the surface engineering of MoS₂ involved by Hg²⁺ ions results in the differential growths of nanostructures and morphological diversities. Naked-eye colorimetric responses to mercury ions, with a low limit of detection of 1.27 nM, are achieved based on the in situ grown heterostructures.

Optical pulse modulators based on layered vanadium diselenide nanosheets

The transition metal disulfides of VB group elements have gradually come into people's field of vision owing to their two-dimensional structure and unique optical properties. Vanadium diselenide (VSe₂) as a kind of transition metal diselenides, is competent for the applications of nonlinear saturable absorption. The dispersion of few-layer VSe₂is prepared by liquid phase exfoliation method. Clearly, it has an obvious layered structure, and the interlayer spacing is 0.31 nm. The VSe₂nanosheets are inserted into the Erbium-doped fiber laser through tapered deposition method and the measured modulation depth is 1.46%. A 1530.5 nm centered 851-fs pulse is observed with the 3.2 nm 3-dB spectral width. The experimental results show that the pulse is persistent under the power of 334 mW, with signal-to-noise ratio of 41 dB. And an up to 552.4 MHz modulation phenomenon is observed around 1560 nm, so is its frequency tunability. This is the first time that VSe₂is used to realize high frequency modulation in fiber laser. It is proved that VSe₂is expected to be a budding material of ultrafast optical modulation devices and widely used in the field of ultrafast photonics.

2 μm passively mode-locked thulium-doped fiber lasers with Ta2AlC-deposited tapered and side-polished fibers

In this work, mode-locked thulium-doped fiber lasers operating in the 2 µm wavelength region were demonstrated using tantalum aluminum carbide (Ta2AlC)-based saturable absorbers (SAs) utilizing the evanescent wave interaction. The Ta2AlC MAX Phase was prepared by dissolving the Ta2AlC powder in isopropyl alcohol and then deposited onto three different evanescent field-based devices, which were the tapered fiber, side-polished fiber, and arc-shaped fiber. Flame-brushing and wheel-polishing techniques were used to fabricate the tapered and arc-shaped fibers, respectively, while the side-polished fiber was purchased commercially. All three SA devices generated stable mode-locked pulses at center wavelengths of 1937, 1931, and 1929 nm for the tapered, side-polished, and arc-shaped fibers. The frequency of the mode-locked pulses was 10.73 MHz for the tapered fiber, 9.58 MHz for the side-polished fiber, and 10.16 MHz for the arc-shaped fiber. The measured pulse widths were 1.678, 1.734, and 1.817 ps for each of the three SA devices. The long-term stability of the mode-locked lasers was tested for each configuration over a 2-h duration. The lasers also showed little to no fluctuations in the center wavelengths and the peak optical intensities, demonstrating a reliable, ultrafast laser system.

Ultrafast Photonics of Ternary RexNb(1-x)S2 in Fiber Lasers

Two-dimensional (2D) transition metal chalcogenides (TMCs) become more attractive upon addition of a third element owing to their unique structure and remarkable physical and chemical properties, which endow these materials with considerable potential for applications in nanoscale devices. In this work, a Re_xNb_(1-x)S₂-based saturable absorber (SA) device for ultrafast photonics applications is studied. The device is assembled by placing Re_xNb_(1-x)S₂ nanosheets with a thickness of 1-3 nm onto a microfiber to increase their compatibility with an all-fiber laser cavity. The prepared Re_xNb_(1-x)S₂-based device exhibits a modulation depth of 24.3%, a saturation intensity of 10.1 MW/cm², and a nonsaturable loss of 28.5%. Furthermore, the Re_xNb_(1-x)S₂-based device is used to generate ultrashort pulses in an erbium-doped fiber (EDF) laser cavity. At a pump power of 260 mW, the EDF laser operates in a conventional soliton mode-locked region. The pulse width is 285 fs, and the repetition frequency is 61.993 MHz. In particular, the bound-state soliton mode-locking operation is successfully obtained in a pump power range of 300-900 mW. The bound-state pulses are formed by doubling identical solitons with a temporal interval of 0.8 ps. The output power is as high as 47.9 mW, and the repetition frequency is 123.61 MHz. These results indicate that the proposed Re_xNb_(1-x)S₂-based SAs have comparable properties to currently used 2D SAs and provide a basis for their application in the field of ultrafast photonics.

Compact omnidirectional multicore fiber-based vector bending sensor

We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0° to 360°. The bending sensor proposed here is highly sensitive even for small bending angles (below 1°).

Hydrothermal-Assisted Synthesis and Stability of Multifunctional MXene Nanobipyramids: Structural, Chemical, and Optical Evolution

Recent advancements in two-dimensional materials have brought MXene (Ti₃C₂) into attention due to its exciting properties as a very promising material for various applications. In this work, we report a novel Ti₃C₂ nanobipyramid (Ti₃C₂ NB) structure obtained through a three-step process involving exfoliation, delamination, and subsequent hydrothermal treatment. The morphological and textural properties at each step of synthesis were studied using an array of experimental techniques such as transmission electron microscopy, scanning electron microscopy, and atomic force microscopy and the chemical properties through X-ray diffraction, Raman, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis. The Ti₃C₂ NBs exhibit fluorescence with an excitation-dependent emission. Further, the effect of temperature and pH on the fluorescence was also investigated, which opens up its scope in bioanalytical applications. Ti₃C₂ NBs showed a ∼43% increase in photoluminescence intensity from pH 3 to 11 while a ∼38% increase with the temperature from 20 to 80 °C. Usually, MXenes are highly susceptible to oxidation, but the Ti₃C₂ NBs were found to be chemically and optically stable even after 30 days. Bestowed with good hydrophilicity, the material exhibited high biocompatibility on the mouse fibroblast cell line L929. Further, L929 cells also showed good cellular adhesion on a Ti₃C₂ NB-modified glass substrate. These properties pave a way for its multifunctional ability as a sensor for pH and temperature as well as bioimaging.