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Bi2Te3 Topological Insulator for Domain-Wall Dark Pulse Generation from Thulium-Doped Fiber Laser
摘要： We have experimentally demonstrated domain-wall (DW) dark pulses from a thulium-doped fiber laser incorporating a topological insulator saturable absorber (SA). The bulk-structured Bi2Te3 was used as the SA, which was constructed on a fiber ferrule platform through the deposition of the Bi2Te3 mixed with distilled water. The DW dark pulses were generated from the thulium-doped fiber laser cavity with a dual wavelength at 1956 nm and 1958 nm. The dark pulse width and the repetition rate were measured as ~10.3 ns and ~20.7 MHz over the pump power of ~80 mW, respectively. To the best of our knowledge, this work is the first demonstrated generation of the DW dark pulse from a thulium-doped fiber laser using nanomaterial-based SA.
关键词： fiber lasers,Bi2Te3,topological insulator,domain-wall dark pulses
更新于2025-11-28 14:23:57
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Electrochemical and surface deformation studies on electrodeposited nanostructured Bi2Te3 thin films
摘要： In this article, we have used double exposure digital holographic interferometry (DEDHI) technique for surface deformation study and hologram recording during synthesis of the Bi2Te3 thin films by electrodeposition method. The synthesized Bi2Te3 thin films were characterized structural, morphological, electrochemical, wettability and surface deformation study. Further the holograms are recorded during the electrodeposition process by varying the concentration of electrolyte. From the recorded fringes the stress, deposited mass and thickness have been calculated. It is observed that the fringe width, mass of deposited thin films, and stress to substrate changes with the concentration of electrolyte. The DEDHI technique is found more reliable for thickness measurement in electrodeposition process. The EIS study confirms that the deposited material is highly conducting.
关键词： Bi2Te3,EIS,Holography,DEDHI,Electrochemical properties,Electrodeposition
更新于2025-11-14 15:16:37
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<sup>125</sup> Te nuclear magnetic resonance and impedance spectroscopy study of topological insulator Bi <sub/>2</sub> Te <sub/>3</sub> nanoparticles mixed with insulating Al <sub/>2</sub> O <sub/>3</sub> nanoparticles
摘要： We have studied topological insulator Bi2Te3 nanoparticles mixed with insulating Al2O3 nanoparticles by means of 125Te nuclear magnetic resonance (NMR) and impedance spectroscopy. Our 125Te NMR lineshape measurements revealed the Knight shift of a satellite peak that increased with the mixing ratio of the Al2O3 nanoparticles, indicating that the mixing increases the surface-to-volume ratio of the Bi2Te3 nanoparticles. It is also shown that the impedance spectroscopy can be employed as a simple and effective means of distinguishing the surface electrical properties of the topological insulators in general.
关键词： surface electrical properties,topological insulator Bi2Te3 nanoparticles,125Te nuclear magnetic resonance,impedance spectroscopy
更新于2025-09-23 15:23:52
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A two-fold engineering approach based on Bi2Te3 flakes towards efficient and stable inverted perovskite solar cells
摘要： Perovskite solar cells (PSCs) are currently the leading thin-film photovoltaic technology owing to their high power conversion efficiency (PCE), as well as their low-cost and facile manufacturing process. Two-dimensional (2D) materials have been reported to improve both the PCE and the stability of the PSCs when incorporated across the device’s layered configuration. Hereby, a two-fold engineering approach is implemented in inverted PSCs by using ultra-thin Bi2Te3 flakes, i.e.: (1) to dope the electron transport layer (ETL) and (2) to form a protective interlayer above the ETL. Thorough steady-state and time-resolved transport analyses reveal that our first engineering approach improves the electron extraction rate and thus the overall PCE (+8% vs. reference cells), as a result of the favourable energy level alignment between the perovskite, the ETL and the cathode. Moreover, the Bi2Te3 interlayer through the second engineering approach, facilitates further the electron transport and in addition protects the underlaying structure against chemical instability effects leading to enhanced device’s performance and stability. By combining the two engineering approaches, our optimised PSCs reach a PCE up to 19.46% (+17% vs. reference cells) and retain more than 80% of their initial PCE, after the burn-in phase, over 1100 h under continous 1 Sun illumination. These performances are among the highest reported in literature for inverted PSCs.
关键词： electron transport layer,Perovskite solar cells,Bi2Te3 flakes,stability,power conversion efficiency
更新于2025-09-23 15:21:01
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Plasmonic Emission of Bullseye Nanoemitters on Bi2Te3 Nanoflakes
摘要： Topological insulators, such as Bi2Te3, have been con?rmed to exhibit plasmon radiation over the entire visible spectral range. Herein, we fabricate bullseye nanoemitters, consisting of a central disk and concentric gratings, on the Bi2Te3 nano?ake. Due to the existence of edge plasmon modes, Bi2Te3 bullseye nanostructures are possible to converge light towards the central disk. Taking advantage of the excellent spatial resolution of cathodoluminescence (CL) characterization, it has been observed that plasmonic behaviors depend on the excitation location. A stronger plasmonic intensity and a wider CL spectral linewidth can be obtained at the edge of the central disk. In order to further improve the focusing ability, a cylindrical Pt nanostructure has been deposited on the central disk. Additionally, the ?nite element simulation indicates that the electric-?eld enhancement originates from the coupling process between the plasmonic emission from the Bi2Te3 bullseye and the Pt nanostructure. Finally, we ?nd that enhancement e?ciency depends on the thickness of the Pt nanostructure.
关键词： bullseye nanostructure,Bi2Te3 nano?akes,plasmonic resonance,cathodoluminescence
更新于2025-09-23 15:19:57
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Thermophotovoltaic Cells Converting Low-Temperature Radiation into Electricity
摘要： Thermophotovoltaic cells, which convert low-temperature radiation into electricity, are of signi?cance due to their potential applications in many ?elds. Here, Bi2Te3/Si thermophotovoltaic cells, which work under the radiation from a blackbody, at a temperature of 300–480 K, are presented. The experimental results show that the cells can output electricity, even under a radiation temperature of 300 K. The band structure of Bi2Te3/Si heterojunctions and the defects in Bi2Te3 thin ?lms lower the conversion e?ciency of the cells. It is also demonstrated that the resistivity of Si and the thickness of Bi2Te3 thin ?lms have important e?ects on Bi2Te3/Si thermophotovoltaic cells. Although the cells’ output power is small, this work provides a possible way to utilize low-temperature radiation.
关键词： Bi2Te3/Si,low-temperature radiation,electricity conversion,Thermophotovoltaic cells
更新于2025-09-23 15:19:57
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Highly Sensitive Photoelectrochemical Biosensor Based on Quantum Dots Sensitizing Bi <sub/>2</sub> Te <sub/>3</sub> Nanosheets and DNA-Amplifying Strategies
摘要： In this work, the Bi2Te3 nanosheets treated by N-vinyl-Pyrrolidinone (NVP) showed the highly sufficient and stable photocurrent for being served as novel photoactive material. Accordingly, with CdTe quantum dots (QDs) sensitizing the Bi2Te3 nanosheets, a photoelectrochemical (PEC) biosensor coupling of DNA amplifying strategies was constructed for sensitive miRNA-21 detection. Initially, the Bi2Te3 nanosheets on electrode have conductive surface states with dissipationless electronic property, thus providing a highly stable photocurrent as well as large surface-to-volume ratio. Then, with the participation of target miRNA-21 and auxiliary DNA, the strand displacement amplification (SDA) took place, thereby opening substantial DNA hairpins for triggering next hybridization chain reaction (HCR). Through the HCR, long DNA tails decorated with CdTe QDs could thus be assembled on electrode for enhancing the photocurrent of Bi2Te3 nanosheets. As a result, the proposed PEC biosensor showed a wide detection range from 10 fM to 100 pM with a detection limit (LOD) of 3.3 fM, displaying a promising avenue to construct simply, ultrasensitive and stable analytical techniques and a tremendous potential in bioanalysis and early clinical diagnosis.
关键词： DNA amplifying strategies,Bi2Te3 nanosheets,sensitive detection,CdTe quantum dots,photoelectrochemical biosensor
更新于2025-09-23 15:19:57
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Bismuth and Bismuth Telluride Thin Films Deposited by MOCVD upon Tapered Fiber Sections as Q-switches for Fiber Lasers
摘要： Lasing regimes of ring erbium ?ber lasers passively Q-switched by means of ?ber tapers coated with thin crystalline ?lms of either Bi2Te3 or Bi as saturable absorbers (SAs) are investigated. 10–15 μm in diameter and 5–10 mm long ?ber tapers are prepared by local chemical etching out of a silica light re?ecting cladding of the standard SMF-28 optical ?ber. Nanometer thick island ?lms of pure Bi and Bi2Te3 are synthesized on the surface of the ?ber tapers by applying the metalorganic chemical vapor deposition (MOCVD). The deposited ?lms are then covered with two di?erent polymers: either polyvinyl acetate (PVA) or polydimethylsiloxane elastomer (PDMSE). The ?ber section with polymer-coated SA ?ber is installed into the ring laser cavity in tandem with the section of an active ?ber. For all the samples a stable generation of microsecond pulses in the Q-switch mode at a wavelength of about 1560 nm is observed. To the best of our knowledge, a passively Q-switched ?ber laser with nanometer Bi ?lms as a saturable absorber is implemented for the ?rst time. It is established that even a small increase in the temperature of the surrounding medium leads to a signi?cant increase in the transmission coe?cient of polymer-coated tapers with deposited SA ?lms, which may be attributed to a decrease in the refractive index of the polymers. The most signi?cant increase in the transmission coe?cient with increasing temperature is observed in tapers coated with PVA, which has a refractive index larger than fused silica.
关键词： MOCVD,Q-switches,polymer coating,saturable absorbers,Bi2Te3,fiber lasers,Bi
更新于2025-09-19 17:13:59
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Polarimetric Three-Dimensional Topological Insulators/Organics Thin Film Heterojunction Photodetectors
摘要： As a state of quantum matter with insulating bulk and gapless surface states, topological insulators (TIs) have huge potential in optoelectronic devices. On the other hand, polarization resolution photoelectric devices based on anisotropic materials have overwhelming advantages in practical applications. In this work, the 3D TIs Bi2Te3/organics thin film heterojunction polarimetric photodetectors with high anisotropic mobility ratio, fast response time, high responsivity, and EQE in broadband spectra are presented. At first, the maximum anisotropic mobility ratio of the Bi2Te3/organics thin film can reach 2.56, which proves that Bi2Te3 can serve as a sensitive material for manufacturing polarization photoelectric devices. Moreover, it is found that the device can exhibit a broad bandwidth and ultrahigh response photocurrent from visible to middle wave infrared spectra (405?3500 nm). The highest responsivity (Ri) of the device can still reach 1.93 AW?1 at 3500 nm. In addition, the ultrahigh external quantum efficiency is 4534% with a fast response time (1.42 ms). Excellent properties mentioned above indicate that TIs/organics heterojunction devices are suitable for manufacturing high-performance photoelectric devices in infrared region.
关键词： polarization resolved,inorganics/organics heterojunction,photodetector,Bi2Te3 thin film,MWIR photodetectors
更新于2025-09-11 14:15:04
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A Bi <sub/>2</sub> Te <sub/>3</sub> Topological Insulator as a New and Outstanding Counter Electrode Material for High-Efficiency and Endurable Flexible Perovskite Solar Cells
摘要： Inverted flexible perovskite solar cells (PSCs) typically employ expensive metals as the counter electrodes, which are brittle and corrodible by perovskite, leading to a sharp performance drop under continuous bending, air exposure, thermal stress or light illumination and eventually retards the commercialization. Herein, a low-cost Bi2Te3 counter electrode was employed by using a simple thermal evaporation process. The resultant device achieved an excellent power conversion efficiency of 18.16%, which was among the highest reported efficiencies, much higher than the reference Ag PSC (15.90%). The improvement should be attributed to the intrinsic suppressed electron backscattering in Bi2Te3 topological insulator. Simultaneously, the Bi2Te3 device obtained a significantly improved mechanical flexibility and long-term operational stability. The present strategy will help to open up a new avenue for future commercialization of flexible photovoltaic applications.
关键词： Topological insulator,Bi2Te3,Flexible perovskite solar cells,Counter electrode,CH3NH3PbI3
更新于2025-09-11 14:15:04