- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Switchable Multi-Color Solution-Processed QD-laser
摘要： In this paper, for the first time, the switchable two-color quantum dot laser has been realized considering solution process technology, which has both simultaneous and lonely lasing capability exploiting selective energy contacts. furthermore, both channels can be modulated independently, which is a significant feature in high-speed data transmission. To this end, utilizing superimposed quantum dots with various radii in the active layer provides the different emission wavelengths. In order to achieve the different sizes of QDs, solution process technology has been used as a cost-effectiveness and fabrication ease method. Moreover, at the introduced structure to accomplish the idea, the quantum wells are used as separate selective energy contacts to control the lasing channels at the desired wavelength. It makes the prominent device have simultaneous lasing at different emission wavelengths or be able to lase just at one wavelength. the performance of the proposed device has been modeled based on developed rate equation by assuming inhomogeneous broadening of energy levels as a consequence of the size distribution of quantum dots and considering tunnel injection of carriers into the quantum dots via selective energy contacts. Based on simulation results, the simultaneous lasing in both or at one of two wavelengths 1.31 μm and 1.55 μm has been realized by the superimposition of two different sizes of InGaAs quantum dots in a single cavity and accomplishment of selective energy contacts. Besides, controlling the quantum dot coverage leads to managing the output power and modulation response at the desired wavelengths. By offering this idea, one more step is actually taken to approach the switchable QD-laser by the simple solution process method.
关键词： solution process technology,high-speed data transmission,multi-wavelength lasing,quantum dot laser,selective energy contacts
更新于2025-09-23 15:21:01
-
Non-Lorentzian Local Density of States in Coupled Photonic Crystal Cavities Probed by Near- and Far-Field Emission
摘要： Recent theories proposed a deep revision of the well-known expression for the Purcell factor, with counterintuitive effects, such as complex modal volumes and non-Lorentzian local density of states. We experimentally demonstrate these predictions in tailored coupled cavities on photonic crystal slabs with relatively low optical losses. Near-field hyperspectral imaging of quantum dot photoluminescence is proved to be a direct tool for measuring the line shape of the local density of states. The experimental results clearly evidence non-Lorentzian character, in perfect agreement with numerical and theoretical predictions. Spatial maps with deep subwavelength resolution of the real and imaginary parts of the complex mode volumes are presented. The generality of these results is confirmed by an additional set of far-field and time-resolved experiments in cavities with larger modal volume and higher quality factors.
关键词： non-Lorentzian local density of states,Purcell factor,quantum dot photoluminescence,photonic crystal cavities,near-field hyperspectral imaging
更新于2025-09-23 15:21:01
-
Graphene quantum dot-gold hybrid nanoparticles integrated aptasensor for ultra-sensitive detection of vitamin D3 towards point-of-care application
摘要： Vitamin D is a sunshine vitamin required by the body for various physiological activities. Deficiency of vitamin D (≤ 29 ng mL-1) can cause dental diseases, sarcopenia, osteoporosis, depression, type 2 diabetes, cancer, etc. Additionally, elevated levels of vitamin D (>150 ng mL-1) can result in numerous infirmities such as anorexia, irregular heartbeat, hypercalcemia, fatigue, etc. Hence, periodic detection can help maintain an appropriate level (≥ 30 ng mL-1) of vitamin D in blood serum. Conventional techniques used for the detection of vitamin D are expensive, time consuming, require skilled work force and a specialised laboratory. Herein, we report a portable electrochemical aptasensor for the detection of vitamin D3 using graphene quantum dot-gold (GQD-Au) hybrid nanoparticles. The developed aptasensor has a linear range of 1 nM – 500 nM, limit of detection (LOD) of 0.70 nM (0.28 ng mL-1), limit of quantification (LOQ) of 2.09 nM (0.84 ng mL-1), sensitivity of 0.90 Ω nM-1 mm-2 and a response time <1 minute. The sensor shows high specificity towards vitamin D3, a good stability, shelf life of over 35 days and nearly 98% recovery with serum samples. The developed sensor has been integrated with controlled electronics, thus establishing a portable prototype.
关键词： electrochemical,graphene quantum dot-gold hybrid,aptasensor,Vitamin D3,nanoparticles
更新于2025-09-23 15:21:01
-
Multispectral imaging of mineral samples by infrared quantum dot focal plane array sensors
摘要： Infrared (IR) spectral imaging is a powerful tool for component analysis and identification in the geological field. In this report, we originally use quantum dot infrared photodetector (QDIP) focal plane arrays (FPAs) with different peak-responsivity wavelengths to analyze the mineral composition of rock samples by IR spectral imaging and show the QDIP’s potential as a solution for some geological problems. After clarifying fundamental characteristics such as the blackbody responsivity, current noise density, and spectral responsivity of QDIPs, we present qualitative and quantitative analyses of mineral samples including conglomerate, sandstone, marble, and dolomite. In the qualitative analysis, we distinguish two different compositions in each rock. In the quantitative analysis, we measure the emittance of dolomite and show the emittance errors. Finally, we discuss which experimental factor determines the quantitative precision most dominantly.
关键词： Quantum dot,Focal plane array,Mineral,Multispectral imaging
更新于2025-09-23 15:21:01
-
The influence of acoustic deformation on the recombination radiation in InAs/GaAs heterostructure with InAs quantum dots
摘要： In the framework of electron-deformation model, the influence of deformation on the energy spectrum of electrons and holes in InAs/GaAs heterostructure with InAs quantum dots (QD) is investigated. The influence of acousto-electronic effects on the modulation of radiation energy at the recombination transition between the ground states of electron and hole in InAs/GaAs heterostructure with InAs quantum dots is investigated. The nature of the amplitude dependence of the modulation of the recombination radiation energy on the QD size and the amplitude of the mechanical stress created by the acoustic wave on the surface of the matrix is established.
关键词： Deformation,Modulation of the energy,Acoustic wave,Quantum dot,Energy of electron and hole
更新于2025-09-23 15:21:01
-
Four-Terminal Tandem Solar Cell with Dye-Sensitized and PbS Colloidal Quantum Dot based Sub-cells
摘要： In this work, high performance four-terminal solution-processed tandem solar cells were fabricated by using dye-sensitized solar cells (DSSC) as top-cells and lead sulfide (PbS) colloidal quantum dot solar cells (CQDSC) as bottom-cells. For dye-sensitized top-cells, three different dye combinations were used while the titanium dioxide (TiO2) scattering layer was removed to maximize the transmission. For the PbS bottom-cells, quantum dots with different size were compared. Over 12% PCE has been achieved by using XL dye mixture and 890 nm PbS QDs, which shows a significant efficiency enhancement when compared to single DSSC or CQDSC sub-cells.
关键词： dye-sensitized solar cell,quantum dot solar cell,PbS,four-terminal tandem,solution-processed
更新于2025-09-23 15:21:01
-
Photovoltaic effect generated by spin-orbit interactions
摘要： An AC electric ?eld applied to a junction comprising two spin-orbit coupled weak links connecting a quantum dot to two electronic terminals is proposed to induce a DC current and to generate a voltage drop over the junction if it is a part of an open circuit. This photovoltaic effect requires a junction in which mirror re?ection symmetry is broken. Its origin lies in the different ways inelastic processes modify the re?ection of electrons from the junction back into the two terminals, which leads to uncompensated DC transport. The effect can be detected by measuring the voltage drop that is built up due to that DC current. This voltage is an even function of the frequency of the AC electric ?eld.
关键词： quantum dot,photovoltaic effect,spin-orbit interactions,DC current,voltage drop
更新于2025-09-23 15:21:01
-
Enhanced Absorptivity of Quantum Dot Infrared Photodetector by Introducing of Metal Nanostructure Layer
摘要： Quantum dot infrared photodetector (QDIP) shows more superior characteristics; however, the low absorption rate is still the fundamental factor restricting the performance of the detector. So in our paper, the QDIP is improved by introducing the metal structure with the strips and holes to increase absorptivity. The results demonstrate that the enhanced QDIP can greatly improve the photon absorptivity up to 98.92% as a result of the local coupling surface plasmon effect, which is 1.23 times than that of the conventional photodetectors without the metal array structures.
关键词： Quantum dot infrared photodetector,Surface plasmon,Metal
更新于2025-09-23 15:21:01
-
High-Efficiency Perovskite Quantum Dot Solar Cells Benefiting from a Conjugated Polymer-Quantum Dot Bulk Heterojunction Connecting Layer
摘要： In this work, we reported an efficient and universal method to fabricate perovskite quantum dot (PQD) solar cells with enhanced efficiency. Through dissolving optimal amount conjugated polymers in PQD matrix solution to fabricate a polymer-QD bulk heterojunction hybrid layer located at PQD/hole transporting layer (HTL) interfaces, the resultant solar cell devices exhibit significantly enhanced short-circuit current density and efficiency. In-depth characterizations indicate that adding optimal conjugated polymer into the PQD film can effectively reduce pin-holes, resulting in more efficient interfacial charge transfer and decreased carrier recombination loss. More importantly, it shows that the highest occupied molecular orbital (HOMO) energy level of the conjugated polymer is crucial for achieving improved carrier transport at the PQD/HTL interfaces. Through rational selection of conjugated polymers, we achieved the best power conversion efficiency of ~14% and 13.2% for CsPbI3 and FAPbI3 PQD based solar cells respectively, situating the forefront of all reported PQD solar cells. These findings would provide insights into well controlling the organic-inorganic interfaces to improve photovoltaic devices.
关键词： interfacial modification,solar cells,perovskite quantum dot,bulk heterojunction,conjugated polymer
更新于2025-09-23 15:21:01
-
Towards bright and pure single photon emitters at 300 K based on GaN quantum dots on silicon
摘要： Quantum dots (QDs) based on III-nitride semiconductors are promising for single photon emission at non-cryogenic temperatures due to their large exciton binding energies. Here, we demonstrate GaN QD single photon emitters operating at 300 K with g(2)(0) = 0.17 ± 0.08. At this temperature, single photon emission rates up to 106 s?1 are reached while g(2)(0) ≤ 0.5 is maintained. Our results are achieved for GaN QDs embedded in a planar AlN layer grown on silicon, representing a promising pathway for future interlinkage with optical waveguides and cavities. These samples allow exploring the limiting factors to key performance metrics for single photon sources, such as brightness and single photon purity. While high brightness is assured by large exciton binding energies, the single photon purity is mainly affected by the spectral overlap with the biexcitonic emission. Thus, the performance of a GaN QD as a single photon emitter depends on the balance between the emission linewidth and the biexciton binding energy. Small GaN QDs with an emission energy in excess of 4.2 eV are promising candidates for future room temperature applications, since the biexciton binding energy becomes comparable to the average emission linewidth of around 55 meV.
关键词： single photon source,GaN,room temperature,wide bandgap,quantum dot
更新于2025-09-23 15:21:01