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Synthesis of ZnxCd1-xSe@ZnO Hollow Spheres in Different Sizes for Quantum Dots Sensitized Solar Cells Application
摘要： ZnxCd1-xSe@ZnO hollow spheres (HS) were successfully fabricated for application in quantum dot sensitized solar cells (QDSSCs) based on ZnO HS through the ion-exchange process. The sizes of the ZnxCd1-xSe@ZnO HS could be tuned from ~300 nm to ~800 nm using ZnO HS pre-synthesized by different sizes of carbonaceous spheres as templates. The photovoltaic performance of QDSSCs, especially the short-circuit current density (Jsc), experienced an obvious change when different sizes of ZnxCd1-xSe@ZnO HS are employed. The ZnxCd1-xSe@ZnO HS with an average size distribution of ~500 nm presented a better performance than the QDSSCs based on other sizes of ZnxCd1-xSe@ZnO HS. When using the mixture of ZnxCd1-xSe@ZnO HS with different sizes, the power conversion ef?ciency can be further improved. The size effect of the hollow spheres, light scattering, and composition gradient structure ZnxCd1-xSe@ZnO HS are responsible for the enhancement of the photovoltaic performance.
关键词： zinc oxide,alloyed quantum dots,sensitized solar cells,hollow spheres
更新于2025-11-14 17:04:02
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Higha??Performance Pseudoplanar Heterojunction Ternary Organic Solar Cells with Nonfullerene Alloyed Acceptor
摘要： The vast majority of ternary organic solar cells are obtained by simply fabricating bulk heterojunction (BHJ) active layers. Due to the inappropriate distribution of donors and acceptors in the vertical direction, a new method by fabricating pseudoplanar heterojunction (PPHJ) ternary organic solar cells is proposed to better modulate the morphology of active layer. The pseudoplanar heterojunction ternary organic solar cells (P-ternary) are fabricated by a sequential solution treatment technique, in which the donor and acceptor mixture blends are sequentially spin-coated. As a consequence, a higher power conversion efficiency (PCE) of 14.2% is achieved with a Voc of 0.79 V, Jsc of 25.6 mA cm?2, and fill factor (FF) of 69.8% compared with the ternary BHJ system of 13.8%. At the same time, the alloyed acceptor is likely formed between two the acceptors through a series of in-depth explorations. This work suggests that nonfullerene alloyed acceptor may have great potential to realize effective P-ternary organic solar cells.
关键词： ternary organic solar cells,sequential spin-coating,pseudoplanar heterojunctions,nonfullerene alloyed acceptors
更新于2025-09-23 15:19:57
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Integral monolayer-scale featured digital-alloyed AlN/GaN superlattices using hierarchical growth units
摘要： Acquiring AlN/GaN digital alloys with matching coherent lattices, atomically sharp interfaces, and negligible compositional fluctuations remains a challenge. In this work, the nature and formation mechanism of the constituent elements of AlN and GaN atomic layers growth was examined by first-principle calculations and experimental demonstration. Basing on the calculated formation enthalpies, we developed a hierarchical growth method wherein AlN and GaN growth units are digitally stacked layer by layer through metal organic vapor-phase epitaxy, which involves the growth sequence instantaneously to control chemical potentials of the hierarchical growth units under different atmospheres. High-resolution X-ray diffraction and transmission electron microscopy confirmed that the hierarchical GaN and AlN growth units of digital-alloyed AlN/GaN structures had coherent lattices, abrupt interfaces, and integral monolayers at the atomic scale. The cathodoluminescence properties featured with single emission, combining with theoretical results, demonstrated that the capability of electronic energies via the digital-alloyed AlN/GaN superlattices. These results provide a basis toward the realization of other digital-alloyed nitride semiconductors.
关键词： digital-alloyed AlN/GaN superlattices,integral monolayer-scale,hierarchical growth units
更新于2025-09-19 17:15:36
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Internal Atomic-Scale Structure Determination and Band Alignment of IIa??VI Quantum Dot Heterostructures
摘要： This work shows that ZnTe/CdSe core/shell quantum dots synthesized by a standard literature procedure in actuality have an alloyed CdxZn1?xTe core. We employ X-ray absorption spectroscopy (XAS) at all four K-shell ionization edges (Zn, Te, Cd, and Se) and perform global ?tting analysis to extract the ?rst-shell bond distances. We combine our XAS results with transmission electron microscopy (TEM) sizing and elemental analyses, which allows us to propose models of the internal particle structure. Our multimodal characterization approach con?rms (1) the presence of Cd?Te bonds, (2) cation alloying in the particle core (and the absence of anion alloying), and (3) a patchy pure-phase CdSe shell. We synthesize particles of di?erent shell thicknesses and performed synthetic control studies that allowed us to discard a ZnTe/CdTe/CdSe core/shell/shell structure and con?rm the alloyed core/shell structure. Our structural analysis is extended with electronic band structure calculations and UV/vis absorption spectroscopy, demonstrating that the alloyed CdxZn1?xTe/CdSe core/shell quantum dots exhibit a direct band gap, di?erent from the predicted type II band alignment of the intended ZnTe/CdSe core/shell quantum dots. This study highlights the challenges with synthesizing II?VI quantum dot heterostructures and the power of XAS for understanding the internal structure of heterogeneous nanoparticles.
关键词： X-ray absorption spectroscopy,alloyed core,core/shell,band alignment,quantum dots
更新于2025-09-19 17:13:59
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Environmentally friendly Mn-alloyed core/shell quantum dots for high-efficiency photoelectrochemical cells
摘要： Colloidal quantum dots (QDs)-based photoelectrochemical (PEC) cells are cost-effective devices showing remarkable solar-to-fuel conversion efficiency. However, the extensive use of highly toxic elements (e.g. Pb and Cd) in QD’s synthesis and device fabrication is still a major challenge towards their practical development. Herein, we fabricate a solar-driven PEC cell based on environment-friendly Mn-alloyed CuInS2 (MnCIS)/ZnS core/shell QDs, showing more favorable band alignment, efficient charge transfer, reduced charge recombination as well as lower charge transfer resistance with respect to the control device fabricated using unalloyed CuInS2 (CIS)/ZnS core/shell QDs. An unprecedented photocurrent density of ~5.7 mA/cm2 with excellent stability was obtained in as-fabricated MnCIS/ZnS core/shell QDs-based PEC device when operated under standard one solar irradiation (AM 1.5G, 100 mW/cm2). These results indicate that the transition metal-alloyed environment-friendly core/shell QDs are promising for next-generation solar technologies.
关键词： Colloidal quantum dots,Photoelectrochemical cells,Mn-alloyed CuInS2,ZnS core/shell,Solar-to-fuel conversion
更新于2025-09-19 17:13:59
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Bright and Color-Stable Blue-Light-Emitting Diodes based on Three-Dimensional Perovskite Polycrystalline Films via Morphology and Interface Engineering
摘要： Substantial progress has been achieved in red and green perovskite light-emitting diodes (PeLEDs). However, blue PeLEDs are still inferior in light-emitting efficiency and luminance compared with their green and red counterparts. Herein efficient blue PeLEDs simultaneously achieving high luminance and high color stability are fabricated based on the polycrystalline perovskites with a 3D Rb?Cs alloyed scaffold. The synergistic manipulation of an isopropanol antisolvent treatment and the PEDOT:PSS/blue perovskite interface modification with RbCl effectively improve the photoluminescence properties of the resultant blue polycrystalline 3D perovskite films and the final electroluminescence performance of the blue PeLEDs. The optimized blue PeLEDs show a maximum external quantum efficiency of 1.66% with an emission peak at 484 nm and a full width at half-maximum of 18 nm as well as CIE coordinates of (0.08, 0.21). Moreover, the optimized blue PeLEDs not only show superior color stability under various luminances but also achieve high luminances. The obtained maximum luminance of 9243 cd m?2 is one of the highest values among the efficient and color-stable blue PeLEDs.
关键词： blue PeLEDs,perovskite light-emitting diodes,Rb?Cs alloyed scaffold,color stability,high luminance
更新于2025-09-19 17:13:59
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Bifacial IFO/(n+pp+)Cz-Si/ITO solar cells with full-area Al-alloyed BSF and Ag-free multi-wire metallization suitable for low-concentration systems
摘要： Bifacial solar cells have received considerable attention due to the potential to achieve higher energy yield compared to monofacial cells. However, in bifacial cells, p+-Si layers are usually produced by boron diffusion, which makes such cells more expensive compared to monofacial cells with a full-area screen-printed Al-alloyed Al-p+ back-surface-field (BSF). Recently, we have demonstrated proof-of-concept that bifacial cells, which, in addition, are also suitable for application in low-concentration systems (3–6 suns), can be produced from commercially available, standard monofacial SiNx/(n+pp+)Cz-Si/Al structures with full-area Al-p+-BSF. For this purpose, the residual Al paste was removed and a number of solar cells were prepared differing in the sheet resistance of the Al-p+-BSF (Rp+), which was varied from 14 Ω/sq to 123 Ω/sq by thinning the Al-p+ layer using one-sided etch-back process. Thinning of the Al-p+-BSF significantly improved the efficiency under 1-sun front/rear-side illumination: from 16.0%/7.5% (at Rp+ = 14 Ω/sq) to 17.5%/11.2% (at Rp+ = 81 Ω/sq). The equivalent efficiency at 1-sun front illumination and 20/50% albedo of 1-sun illumination increased from 17.7%/20.1% (at Rp+ = 14 Ω/sq) to 19.9%/23.5% (at Rp+ = 81 Ω/sq). In this paper, we present the results of systematic study of the developed bifacial cells. Thinning-induced changes in the properties of the cells are analyzed in detail. The critical aspects which might explain the performance of the developed cells are addressed. In addition, bifacial cells are compared with standard monofacial cells fabricated using the precursor of the same batch.
关键词： Ultrasonic spray pyrolysis,Transparent conductive oxide,Ag-cost reduction,Bifacial concentrator silicon solar cell,Multi-wire metallization,Al-alloyed BSF
更新于2025-09-19 17:13:59
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Zn-Alloyed All-Inorganic Halide Perovskite-Based White Light-Emitting Diodes with Superior Color Quality
摘要： Recently, lead halide perovskite nanocrystals (NCs) have gained tremendous attention in optoelectronic devices due to their excellent optical properties. However, the toxicity of lead limits their practical applications. Here, the synthesis of Zn2+-alloyed CsZnxPb1-xX3 (up to 15%) NCs is reported to achieve lead-reduced white light-emitting diodes (WLEDs). The incorporation of Zn2+ into CsPbX3 host NCs results in a lattice contraction, without altering the structure and morphology, which has a direct effect on the optical properties. The blue-shifts in the photoluminescence emission and increase in bandgap is observed while retaining high photoluminescence quantum yield. Then by engineering the different compositions of halides for 15% Zn2+-alloyed CsZnxPb1-xX3 NCs, tunable emission (411–636 nm) is obtained. Notably, the WLEDs are experimentally demonstrated employing the lead-reduced NCs (blue, green, yellow, and red). By varying the ratios of the amount of NCs, white lights with a tunable correlated-color temperature (2218–8335 K), an exemplary color-rendering index (up to 93) and high luminous efficacy of radiation (268–318 lm·W?1) are obtained. Best of our knowledge, these are superior to other reported WLEDs based on CsPbX3 NCs doped with transition metal ions. This work places the halide perovskite NCs one-step closer in designing the environmentally benign and energy-efficient WLEDs.
关键词： White Light-emitting Diodes,Zn-Alloyed,Color Quality,All-inorganic Halide perovskite
更新于2025-09-12 10:27:22
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Alloyed Ag2SexS1-x quantum dots with red to NIR shift: the band gap tuning with dopant content for energy harvesting applications
摘要： Alloyed quantum dots have pulled in a large consideration because of their fascination from visible to near infrared regime. In this work, quantum dots of alloyed Ag2SexS1-x (x = 0, 0.4, 0.6, 1.0) system are synthesized by making use of a simple intermediate temperature method. The structure and morphology of Ag2SexS1-x quantum dots are examined through X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, and Raman spectroscopy. The X-ray diffraction data indicates monoclinic and orthorhombic structure of Ag2SexS1-x quantum dots. The size and composition controlled optical bandgap of Ag2SexS1-x quantum dots is meticulously looked into by Ultraviolet-Visible-Near Infrared absorption spectroscopy. The size of alloyed Ag2SexS1-x quantum dots varies from 3.5 nm to 4.8 nm. The bandgap of Ag2SexS1-x quantum dots has varied from 1.35 eV to 0.88 eV as calculated by Tauc plot. The observed values of bandgap indicate quantum confinement in two regimes-weak and strong confinement regimes. The results show that quantum confinement depends on both the size and composition of Ag2SexS1-x quantum dots. The alloying of Se to Ag2S has been confirmed using the Raman spectroscopy. These alloyed quantum dots might be reasonable for catching solar energy particularly from visible to NIR regime.
关键词： Alloyed Quantum Dots,Solar Energy,Quantum Confinement,Optical Band Gap
更新于2025-09-12 10:27:22
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Synthesis of Alloyed ZnSeTe Quantum Dots as Bright, Color-Pure Blue Emitters
摘要： Considering a strict global environmental regulation, fluorescent quantum dots (QDs) as key visible emitters in the next-generation display field should be compositionally non-Cd. When compared to green and red emitters obtainable from size-controlled InP QDs, development of non-Cd blue QDs remains stagnant. Herein, we explore synthesis of non-Cd, ZnSe-based QDs with binary and ternary compositions toward blue photoluminescence (PL). First, size increment of binary ZnSe QDs is attempted by a multiply repeated growth until blue PL is attained. Although this approach offers a relevant blue color, excessively large-sized ZnSe QDs inevitably entail a low PL quantum yield (QY). As an alternative strategy to the above size enlargement the alloying of high-band gap ZnSe with lower-band gap ZnTe in QD synthesis is carried out. These alloyed ternary ZnSeTe QDs after ZnS shelling exhibit systematically tunable PL of 422?500 nm as a function of Te/Se ratio. Analogous to state-of-the-art heterostructure of InP QDs with a double-shelling scheme, an inner shell of ZnSe is newly inserted with different thicknesses prior to an outer shell of ZnS, where the effects of the thickness of ZnSe inner shell on PL properties are examined. Double-shelled ZnSeTe/ZnSe/ZnS QDs with an optimal thickness of ZnSe inner shell are then employed for all-solution-processed fabrication of blue QD-light-emitting diode (QLED). The present blue QLED as the first ZnSeTe QD-based device yields a peak luminance of 1195 cd/m2, current efficiency of 2.4 cd/A, and external quantum efficiency of 4.2%, corresponding to the record values reported from non-Cd blue devices.
关键词： external quantum efficiency,alloyed ZnSeTe quantum dots,Non-Cd blue emitters,ZnSe inner shell,quantum dot-light-emitting diode
更新于2025-09-11 14:15:04