查找使用阿拉丁产品的科研文献

Optimization of light conversion efficiency in inkjet-printed cadmium selenide quantum dot layers

Xianzhen Huang,Yun Ye,Jiaqi Gao,Xingke Zheng

Color conversion layers are extensively utilized in flat panel display technology for their capacity to provide a wide color gamut and improved resolution, along with exceptional design flexibility. The uniformity and thickness of cadmium selenide (CdSe) quantum dot (QD) films are often difficult to control in the preparation of color conversion layers. Interestingly, it is possible to precisely deposit QDs by inkjet printing to improve material utilization. Color conversion layers with optimized spectral properties and light conversion efficiency are successfully prepared by inkjet printing. We employ inkjet printing technology to fabricate CdSe QD color conversion layers with precise control over layer thickness. The effects of layer thickness on spectral properties and light conversion efficiency are systematically investigated. It is found that a layer thickness of 5.5 μm achieves the highest light conversion efficiency at 20.4%, with efficiency decreasing as thickness increases to 6 μm. In addition, it is observed that blue light transmittance decreases from 47.2% to 11.4% with increasing layer thickness, highlighting the importance of thickness control in optimizing spectral properties.

Water Effects on Colloidal Semiconductor Nanocrystals: Correlation of Photophysics and Photochemistry

Zhuang Hu,Yufei Shu,Haiyan Qin,Xiaofei Hu,Xiaogang Peng

With high-quality CdSe/CdS core/shell nanocrystals as the main model system and under a controlled atmosphere, responses of photoexcited semiconductor nanocrystals to two active species (water and/or oxygen) in an ambient environment are studied systematically. Under photoexcitation, although high-quality semiconductor nanocrystals in either thin solid films or various solutions have a near-unity photoluminescence quantum yield, there is still a small probability (∼10–5 per photon absorbed) to be photoreduced by the water molecules efficiently accumulated in the highly hydrophilic nanocrystal–ligands interface. The resulting negatively charged nanocrystals are the starting point of most photophysical variations, and the hydroxyl radical─key photo-oxidation product of water─plays the main role for initiating various photochemical processes. Depending on the supplementation of water to the interface, accessibility to oxygen, photoirradiation power, type of matrices, type of measurement schemes, and solubility of nanocrystals in the solution, various photophysical/photochemical phenomena─either reported or not reported in the literature─are reproducibly observed. Results confirm that photophysical properties and photochemical reactions can be well-correlated, offering a unified and unique basis for fundamental studies and the design of processing techniques in industry.

Multifunctional and Multicolor Perovskite-CdSe Quantum Dots Diodes for Pulse Oximetry

Ting Zheng,Mingchao Zhu,Xi Luo,Fanghao Ye,Ming Wang,Yang He,Yitong Zhang,Zhenwei Lin,Zhiqing Zhang,Xu Ping,Hang Zhou,Lei Lu,Guijun Li

A conventional pulse oximeter system is composed of two light sources with different peak emission wavelengths and a photodetector. Integrating these three independent components into one single device will absolutely simplify the system design and create a miniaturized size of the product. Here, we demonstrate a bilayer perovskite-CdSe quantum dot (hereafter perovskite-QD) diode capable of voltage-tunable green/red emission and photodetection. The proposed diode also presents an intriguing feature of simultaneous light emission and detection, which is explored as regards the diode being used as a photoconductor when the positive bias is larger than the built-in voltage. The multifunctional and multicolor diode is further employed in a reflective pulse oximeter system, as either the multicolor light sources or the sensing unit in the system provide accepted and trustful results for heart rate and arterial blood oxygenation. Our work provides a possible avenue for the simplification of the pulse oximetry with a compact and miniaturized design in the future.

Synergistic integration of photoelectron utilization and by-product pathway suppression for microbial production of bacitracin

Rui Bai,Wei Chen,Xudong Zhou,Junpeng Li,Yi He,Yong Xiao,Feng Zhao

Bacitracin is renowned for its broad-spectrum antimicrobial activity and low propensity to induce resistance. However, how to achieve efficient bacitracin production remains a significant challenge. In this study, we developed a Bacillus licheniformis -CdSe biohybrid system that operates under sunlight, employing dual regulatory strategies of "increasing incomes" and "cutting expenses" to achieve efficient bacitracin production. For the increasing incomes strategy: CdSe converted solar energy into photoelectrons, providing B. licheniformis with additional energy and accelerating intracellular energy metabolism; For the cutting expenses strategy: Light exposure induced a metabolic pathway rearrangement in B. licheniformis , suppressing the pathway of pulcherrimin synthesis, thereby conserving energy and redirecting resources toward bacitracin synthesis. By integrating these two regulatory strategies, the bacitracin yield exhibited a remarkable increase, achieving a cumulative concentration of 390.9 mg·L −1 within 24 h. Comprehensive analyses, including biochemistry, electrochemistry, proteomics, and transcriptomics, demonstrated that light optimizes energy allocation by suppressing metabolic byproducts in B. licheniformis , thereby enhancing selectivity for the target product. CdSe efficiently harvested solar energy, accelerating intracellular regeneration of ATP and NAD( P )H, and promoting the production of precursor amino acids, ultimately boosting bacitracin synthesis. This study provides insight into how to design microbe-semiconductor biohybrid systems for the sustainable synthesis of high-value chemicals.

In Situ Growth Visualization Nanochannel Membrane for Ultrasensitive Copper Ion Detection under the Electric Field Enrichment

Hongli Gao,Ruikun Sun,Lei He,Zhong-Ji Qian,Chunxia Zhou,Pengzhi Hong,Shengli Sun,Rijian Mo,Chengyong Li

The transport of ionic species through nanochannels plays an important role in the basic research and practical application of nanofluidic devices. Here, a visualized CdSe@ZIF-8/PAA nanochannel membrane was created by employing in situ growth of zeolite imidazole skeleton (ZIF-8) and CdSe quantum dots (CdSe QDs) on a porous anodized aluminum oxide (PAA) membrane surface using CdSe QDs, 2-methylimidazole, and zinc nitrate as the precursor solvents. ZIF-8 is a kind of metal–organic framework, a microporous material that possesses strong metal adsorption capacity. In addition, CdSe quantum dots have fluorescent properties. The nanochannel membrane detects copper ions (Cu2+) by quenching the fluorescence intensity by the interaction between Cu2+ and Se and S atoms. The direct potential of 5 V was applied to achieve Cu2+ enrichment at the nanochannel interface, and the fluorescence change was observed. The CdSe@ZIF-8/PAA nanochannel membrane has a good linear range of concentration (0.01 pM–1 μM) for Cu2+ detection. With the help of nanochannel enrichment, its detection limit reaches 4 fM. In addition, this nanochannel membrane has good selectivity for Cu2+.

Constructing photothermal core-shell photonic crystal structure for efficient photocatalytic CO2 reduction

Yukai Chen,Yiyi Ji,Ruizhe Wang,Dan Wang,Rulin Dong,Hengming Huang,Jiaojiao Fang

To solve the problems of low utilization over the solar spectrum, elevating the photon absorption efficiency and exploiting long-wavelength photons are of great significance. Herein, a CdSe/polydopamine(PDA)@SiO 2 core–shell opal photonic crystal structure with excellent photothermal effect and photon absorption was fabricated for the first time. The photonic bandgap (PBG) effect and the slow photon effect of the photonic crystal structure helps the absorbing of photons and the photothermal effect of PDA coating shells provides higher reacting temperature for photocatalysis. Consequently, the S2P0 sample (without PDA coating) whose PBG is consistent with the absorption edge of CdSe photocatalyst exhibits a three times higher CO 2 reduction efficiency. Benefited from the photothermal effect of PDA, the S2P20 sample (20% PDA coating) shows a 4.77-fold efficiency than the blank sample, proving the reliability of the design. Moreover, the PDA shells enhance the adhesion for robust photonic crystal films and show other applications in fields like textiles. This work demonstrates a synergistic utilization of photothermal effect and photonic crystal structure for efficient photocatalytic CO 2 reduction and revealing more potential applications.

A novel cadmium-containing wastewater treatment method: Bio-immobilization by microalgae cell and their mechanism

Zhengwei Zhang,Kun Yan,Ling Zhang,Qian Wang,Ruixin Guo,Zhengyu Yan,Jianqiu Chen

Heavy metal cadmium (Cd) has drawn tremendous comcern due to its rigorous environmental and health hazards. Herein, we have presented an efficient and economical strategy for the removal and recycling of hazardous Cd ions using microalgae cells as the bioreactors. Remarkably, the green bio-platform for the bioproduction of CdSe nanoparticles (NPs) was developed depending on their orderly regulated and sustainable cellular environment. The biofabricated CdSe NPs manifested favorable photoluminescence properties, and presented well monodispersed spherical morphology and certain crystallinity structure with mean size of smaller than 7 nm. Especially, the fluorescence “turn off” sensing system based on the CdSe NPs was established to detect Hg 2+ . The nanosensor enables the quantitative analyses of Hg 2+ with a linear range of 0–2.0 μM and a detection limit of 0.021 μM. Furthermore, it was preliminarily speculated that the reducing biomolecules in the algae cells could be involved in the formation of CdSe NPs. This work not only provides new insights into the removal and recycling of hazardous Cd ions, but also brings a promising route for biosynthesis of CdSe NPs.

Stability and luminescence properties of CsPbBr3/CdSe/Al core-shell quantum dots

Heng Yao,Anjiang Lu,Zhongchen Bai,Jinguo Jiang,Shuijie Qin

To improve the stability and luminescence properties of CsPbBr3 QDs, we proposed a new core-shell structure for CsPbBr3/CdSe/Al quantum dots (QDs). By using a simple method of ion layer adsorption and a reaction method, CdSe and Al were respectively packaged on the surface of CsPbBr3 QDs to form the core-shell CsPbBr3/CdSe/Al QDs. After one week in a natural environment, the photoluminescence quantum yields of CsPbBr3/CdSe/Al QDs were greater than 80%, and the PL intensity remained at 71% of the original intensity. Furthermore, the CsPbBr3/CdSe/Al QDs were used as green emitters for white light-emitting diodes (LEDs), with the LEDs spectrum covering 129% of the national television system committee (NTSC) standard color gamut. The core-shell structure of QDs can effectively improve the stability of CsPbBr3 QDs, which has promising prospects in optoelectronic devices.

Oxygen Stabilizes Photoluminescence of CdSe/CdS Core/Shell Quantum Dots via Deionization

Zhuang Hu,Shaojie Liu,Haiyan Qin,Jianhai Zhou,Xiaogang Peng

By taking advantage of well-defined spectroscopic signatures of high-quality CdSe/CdS core/shell QDs, the effects of oxygen on photoluminescence (PL) of QDs were studied systematically and quantitatively at both single-dot and ensemble (on substrate and in solution) levels, which reveals a unified yet simple picture. With a sufficient amount of oxygen in the system during photoexcitation, the core/shell QDs in all forms would be deionized timely from the photogenerated and inefficient trion state back to the efficient single-exciton state, with superoxide radicals as the reduction product of oxygen. Under a given excitation power, rates of both spontaneous deionization and photodeionization channels increased by increasing the oxygen pressure, but photoionization of the QDs was barely affected by the oxygen pressure. While stabilizing PL by oxygen was identified for both CdSe plain core and CdSe/CdS core/shell QDs, irreversible photocorrosion was only observed for CdSe plain core QDs, suggesting the importance of high-quality epitaxial shells for QDs in various applications.

CdSe Quantum Dots Enable High Thermoelectric Performance in Solution-Processed Polycrystalline SnSe

Wei Dou,Yaru Gong,Xinqi Huang,Yanan Li,Qingtang Zhang,Yuqi Liu,QinXuan Xia,Qingyang Jian,Deshang Xiang,Di Li,Dewei Zhang,Shihua Zhang,Pan Ying,Guodong Tang

Here, a high peak ZT of ≈2.0 is reported in solution-processed polycrystalline Ge and Cd codoped SnSe. Microstructural characterization reveals that CdSe quantum dots are successfully introduced by solution process method. Ultraviolet photoelectron spectroscopy evinces that CdSe quantum dots enhance the density of states in the electronic structure of SnSe, which leads to a large Seebeck coefficient. It is found that Ge and Cd codoping simultaneously optimizes carrier concentration and improves electrical conductivity. The enhanced Seebeck coefficient and optimization of carrier concentration lead to marked increase in power factor. CdSe quantum dots combined with strong lattice strain give rise to strong phonon scattering, leading to an ultralow lattice thermal conductivity. Consequently, high thermoelectric performance is realized in solution-processed polycrystalline SnSe by designing quantum dot structures and introducing lattice strain. This work provides a new route for designing prospective thermoelectric materials by microstructural manipulation in solution chemistry.

Luminescence Change of CdS and CdSe Quantum Dots on a Ag Film

Lian Hu,Tianning Xu,Huaxin Zhu,Chaoqun Ma,Guoqing Chen

Enhanced luminescence of an emitter on a Ag film is usually ascribed to the resonant surface plasmons. In these studies, the solid cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dot/silver (QD/Ag) hybrids were prepared, and the luminescence characteristics of these QD/Ag hybrids were measured. It is found that the enhancement of the trap state emission (TSE) is related to the QD size. The TSE features of the annealed QD/Ag hybrids are insensitive to the morphology of the Ag film. We used the wet and dry methods to separate the QD and Ag components and found that the photoluminescence (PL) of the QD component was permanently changed from the initial state. The PL modification is ascribed to the Ag+ doping effect rather than the surface plasmons. This doping method uses pure Ag as the Ag+ ion source. In this case, though the CdS and CdSe QD/Ag hybrids are the solid state, the cation exchange between Ag+ and Cd2+ ions can still occur on the QD surface. Even a small amount of Ag can efficiently influence the luminescence of the QDs embedded in the poly(methyl methacrylate) matrix. A hypothetical model was proposed to explain the PL modification of the QD/Ag hybrid with and without annealing. Using this dry method for doping, the transparent luminescence label can be prepared easily, and the doped QDs can be further doped with Ag+ dopants.

Ultrapure Green Light-Emitting Diodes Based on CdSe/CdS Core/Crown Nanoplatelets

Zuoliang Wen,Chaojian Zhang,Ziming Zhou,Bing Xu,Kai Wang,Kie Leong Teo,Xiao Wei Sun