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Zinc ions modified InP quantum dots for enhanced photocatalytic hydrogen evolution from hydrogen sulfide
摘要： Through direct addition of inorganic zinc ions into the solution of indium phosphide quantum dots (InP QDs) at ambient environment, we here present a facile but effective method to modify InP QDs for photocatalytic hydrogen evolution from hydrogen sulfide (H2S). X-ray diffraction patterns and transmission electron microscopic images demonstrate that zinc ions have no significant influence on the crystal structure and morphology of InP QDs, while X-ray photoemission spectra and UV–Vis diffuse and reflectance spectra indicate that zinc ions mainly adsorbed on the surface of InP QDs. Photocatalytic results show the average hydrogen evolution rate has been enhanced to 2.9 times after modification and H2S has indeed involves in the hydrogen evolution process. Steady-state and transient photoluminescence spectra prove that zinc ions could effectively eliminate the surface traps on InP QDs, which is crucial to suppress the recombination of charge carriers. In addition, the electrostatic interaction between zinc ions and the surface sulfide from InP QDs could mitigate the repulsion between QDs and sulfide/hydrosulfide, which may promote the surface oxidative reaction during photocatalysis. This work avoids the traditional harsh and complicated operations required for surface passivation of QDs, which offers a convenient way for optimization of QDs in photocatalysis.
关键词： Hydrogen sulfide,Photocatalytic hydrogen evolution,InP quantum dots,Surface modification
更新于2025-10-22 19:38:57
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Mg-Doped ZnO Nanoparticle Films as the Interlayer between the ZnO Electron Transport Layer and InP Quantum Dot Layer for Light-Emitting Diodes
摘要： Because the wide emission spectrum tunability which range from the visible region to the near-infrared, InP based colloidal quantum dots (QDs) show great promise for use in next-generation full-color displays and solid state lighting. The performance-improved InP QD based light-emitting devices (QLEDs) were fabricated by using Mg doped-ZnO nanoparticles (ZnMgO NPs) as an interlayer between ZnO electron transport layer and active InP QD layer. It is found that ZnMgO NPs can reduce electron injection and suppress exciton quenching which is attributed to the improvement of charge balance in the devices. We successfully demonstrated higher maximum current efficiencies of 5.46 and 5.91 cd/A than the references (2.31 and 2.36 cd/A) without the ZnMgO NP layer in highly efficient red and green QLEDs, respectively. These results signify an effective approach to improve heavy-metal-free QLEDs for commercial applications.
关键词： InP quantum dots,Mg doped-ZnO,electron transport layer,light-emitting diodes,charge balance
更新于2025-09-23 15:21:01
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Zinc Oxo Clusters Improve the Optoelectronic Properties on Indium Phosphide Quantum Dots
摘要： This study explored the effect of zinc precursors on the optical properties of InP quantum dots (QDs) by controlling the reactivity of zinc carboxylates via a simple thermal treatment. The formation of zinc oxo clusters, Zn4O(oleate)6 and Zn7O2(oleate)10, during the thermal decomposition of zinc oleate was confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. By using the zinc oxo clusters as reaction precursors, high-quality InP QDs with high photoluminescence quantum yield (PLQY) and narrow full width at half maximum (FWHM) were synthesized. (Green QDs: PLQY=95%, FWHM=37 nm. Red QDs: PLQY=84%, FWHM=40 nm) The analysis results showed that the improved optoelectronic properties were achieved by two important functions of the zinc oxo clusters: 1) suppressing the rapid depletion of the highly reactive phosphorus source and inducing size uniformity of the In(Zn)P core, and 2) facilitating the formation of an oxidized buffer layer, which effectively controls defects. Likewise, the use of reactivity-controlled species is an effective strategy for the synthesis of well-designed QDs.
关键词： full width at half maximum,InP quantum dots,optoelectronic properties,photoluminescence quantum yield,zinc oxo clusters
更新于2025-09-23 15:19:57
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Enhanced thermal stability of InP quantum dots coated with Al-doped ZnS shell
摘要： Colloidal InP quantum dots (QDs) have attracted a surge of interest as environmentally friendly light-emitters in downconversion liquid crystal displays and light-emitting diodes (LEDs). A ZnS shell on InP-based core QDs has helped achieve high photoluminescence (PL) quantum yield (QY) and stability. Yet, due to the difficulty in the growth of a thick ZnS shell without crystalline defects, InP-based core/shell QDs show inferior stability against QY drop compared to Cd chalcogenide precedents, e.g., CdSe/CdS core/thick-shell QDs. In this work, we demonstrate the synthesis of InP-based core/shell QDs coated with an Al-doped ZnS outer shell. QDs with an Al-doped shell exhibit remarkable improvement in thermal and air stability even when the shell thickness is below 2 nm, while the absorption and PL spectra, size, and crystal structure are nearly the same as the case of QDs with a pristine ZnS shell. X-ray photoelectron spectroscopy reveals that Al3+ in Al-doped QDs forms an Al-oxide layer at elevated temperature under ambient atmosphere. The as-formed Al-oxide layer blocks the access of external oxidative species penetrating into QDs and prevents QDs from oxidative degradation. We also trace the chemical pathway of the incorporation of Al3+ into ZnS lattice during the shell growth. Furthermore, we fabricate QD-LEDs using Al-doped and undoped QDs and compare the optoelectronic characteristics and stability.
关键词： quantum yield,QD-LEDs,photoluminescence,Al-doped ZnS shell,X-ray photoelectron spectroscopy,InP quantum dots,thermal stability
更新于2025-09-19 17:13:59
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Strain in InP/ZnSe, S core/shell quantum dots from lattice mismatch and shell thickness—Material stiffness influence
摘要： We investigate the buildup of strain in InP quantum dots with the addition of shells of the lower-lattice constant materials ZnSe and ZnS by Raman spectroscopy. Both materials induce compressive strain in the core, which increases with increasing shell volume. We observe a difference in the shell behavior between the two materials: the thickness-dependence points toward an influence of the material stiffness. ZnS has a larger Young’s modulus and requires less material to develop stress on the InP lattice at the interface, while ZnSe requires several layers to form a stress-inducing lattice at the interface. This hints at the material stiffness being an additional parameter of relevance for designing strained core/shell quantum dots.
关键词： Raman spectroscopy,ZnSe,ZnS,strain,material stiffness,InP quantum dots
更新于2025-09-19 17:13:59
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Development of InP Quantum Dot-based Light Emitting Diodes
摘要： High performance quantum dot light emitting diode (QLED) is being considered as the next generation technology for energy efficient solid-state lighting and displays. InP QLED is the most promising alternative of the toxic CdSe QLED. Unlike the problems of poor hole injection in CdSe-based QLED, highly delocalized electrons and parasitic emissions are serious problems in green-emitting InP QLED. The loss mechanism and device physics in InP QLED have not been sufficiently studied since the first report of InP QLED in 2011. This review summarized the recent efforts on improving the performance of InP QLED, from the perspectives of core/shell structures to optimization of carrier transport layers. It is our intention to conduct a review as well as clarify some previous misunderstandings on the device physics in InP QLED, and provide some insights for the possible solutions of the challenging problems in InP QLED.
关键词： InP quantum dots,carrier transport layers,parasitic emissions,core/shell structures,QLED
更新于2025-09-16 10:30:52
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Synthesis of Colloidal Blue-Emitting InP/ZnS Core/Shell Quantum Dots with the Assistance of Copper Cations
摘要： Colloidal InP quantum dots (QDs) have been considered as one of the most promising candidates for the applications in display and bio-label due to intrinsic toxicity-free and high photoluminescence. On account of the uncontrollable nucleation and growth for the synthesis of InP, it remains a challenge to obtain high-quality blue-emitting InP QDs with uniform size distribution. Herein, we employ a novel synthetic approach for producing blue-emitting InP/ZnS core/shell QDs with the assistance of copper cations. The studies reveal that the copper ions could combine with phosphorus precursor to form hexagonal Cu3-xP nanocrystals, which competed with the nucleation process of InP QDs, resulting in the smaller sized InP QDs with blue photoluminescence emission. After the passivation of InP QDs with ZnS shell, the synthesized InP/ZnS core/shell QDs present bright blue emission (~425 nm) with photoluminescence quantum yield (PLQY) of ~25%, which is the shortest wavelength emission for InP QDs till now. This research provides a new way to synthesize ultra-small semiconductor nanocrystals.
关键词： InP/ZnS core/shell,blue-emitting,Colloidal InP quantum dots,photoluminescence quantum yield,copper cations
更新于2025-09-12 10:27:22
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[IEEE 2019 34th Symposium on Microelectronics Technology and Devices (SBMicro) - Sao Paulo, Brazil (2019.8.26-2019.8.30)] 2019 34th Symposium on Microelectronics Technology and Devices (SBMicro) - Transition Energy Calculations of Type II In(As)P/InGaP Quantum Dots for Intermediate Band Solar Cells
摘要： In this work, we perform computational simulations of InAsP type II quantum dots for an intermediate band solar cell. We have varied parameters such as height, width and percentage of P of the quantum dots alloy to determine their influence on the optical transitions` energies and electronic confinement within the quantum dots.
关键词： simulation,energy transitions,InP quantum dots,type II quantum dots
更新于2025-09-12 10:27:22
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Two-state lasing at room temperature in InAs/InP quantum dots
摘要： The two-state lasing conditions at room temperature in InAs/InP quantum dot (QD) lasers under a continuous wave electrical bias current are studied. It is found that excited state (ES) lasing is promoted by moderately decreasing spacer thickness and increasing dot-size dispersion in a QD stack, and the physical origins are due to the increased bottleneck effect and inhomogeneous broadening. Moreover, it is proved theoretically that ground state (GS) lasing with high inhomogeneous broadening may result in high phase and intensity noise at a high bias current. Therefore, an appropriate spacer thickness together with appropriate inhomogeneous broadening is critical to the GS and/or ES lasing, which helps an optimal design of laser geometry.
关键词： two-state lasing,spacer thickness,room temperature,InAs/InP quantum dots,inhomogeneous broadening,dot-size dispersion,intensity noise,continuous wave electrical bias,bottleneck effect,phase noise
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - InP Quantum Dot Mode-Locked Lasers and Materials Studies
摘要： InP/GaInP quantum dot laser structures exhibiting broad optical gain spectra suitable for mode-locking have been demonstrated. Two-section narrow ridge passive mode-locked lasers were fabricated from this material. Mode-locking conditions have been investigated for devices with different cavity lengths, with maximum frequency of 15.21 GHz.
关键词： Mode-Locked Lasers,InP Quantum Dots,Optical gain and absorption
更新于2025-09-11 14:15:04