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1. Strongly confined Te quantum dots as building blocks for single photon sources

   https://doi.org/10.1016/j.mtquan.2025.100034  

   Subedi, Rajendra; Ruiz-Zepeda, Francisco; Woli, Yagya Bahadur; Hoang, Thang Ba; Chaste, Julien; Herth, Etienne; Guisbiers, Grégory (June 2025, Materials Today Quantum)

   Tellurium is a heavy chemical element exhibiting chirality, anisotropy, and strong spin-orbit coupling; conse quently, displaying a huge potential in quantum hardware technologies. In this article, tellurium quantum dots, with sizes around 19 ± 3 nm and energy bandgap around 2.4 eV, were successfully synthesized by pulsed laser ablation in liquids (PLAL). The synthesis was performed by using a nanosecond Nd:YAG laser emitting at 1064 nm and pulsing the laser beam at 1 kHz. Toluene (C6H5CH3) was used as a solvent to avoid oxidation of the dots. Non-polarized and polarized Raman spectroscopy as well as X-Ray diffraction were performed on the dots to study their quantum confinement and anisotropy. Finally, strongly confined tellurium quantum dots were obtained; and, their properties underline their potential as quantum light sources. 

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2. Effect of Synthesis Process, Synthesis Temperature, and Reaction Time on Chemical, Morphological, and Quantum Properties of Carbon Dots Derived from Loblolly Pine

   https://doi.org/10.3390/biomass2040017  

   Quaid, Thomas; Ghalandari, Vahab; Reza, Toufiq (December 2022, Biomass)

   In this study, carbon dots are synthesized hydrothermally from loblolly pine using top-down and bottom-up processes. The bottom-up process dialyzed carbon dots from hydrothermally treated process liquid. Meanwhile, hydrochar was oxidized into carbon dots in the top-down method. Carbon dots from top-down and bottom-up processes were compared for their yield, size, functionality, and quantum properties. Furthermore, hydrothermal treatment temperature and residence time were evaluated on the aforementioned properties of carbon dots. The results indicate that the top-down method yields higher carbon dots than bottom-up in any given hydrothermal treatment temperature and residence time. The size of the carbon dots decreases with the increase in reaction time; however, the size remains similar with the increase in hydrothermal treatment temperature. Regarding quantum yield, the carbon dots from the top-down method exhibit higher quantum yields than bottom-up carbon dots where the quantum yield reaches as high as 48%. The only exception of the bottom-up method is the carbon dots prepared at a high hydrothermal treatment temperature (i.e., 260 °C), where relatively higher quantum yield (up to 18.1%) was observed for the shorter reaction time. Overall, this study reveals that the properties of lignocellulosic biomass-derived carbon dots differ with the synthesis process as well as the processing parameters. 

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3. A universal high-resolution micro-patterning technique for solution-processed materials

   https://doi.org/10.37188/lam.2025.015  

   Velpugonda, John Leo; Varnakavi, Naresh; Yerich, Matthew; Lin, Lih Y (March 2025, Light: Advanced Manufacturing)

   A universal method of micro-patterning thin quantum dot films is highly desired by industry to enable integration of quantum dot materials with optoelectronic devices. Many of the methods reported so far, including specially engineered photoresist or ink-jet printing, are either of poor yield, resolution limited, difficult to scale for mass production, overly expensive or sacrifice some optical quality of the quantum dots. In our previous work, we presented a dry photolithographic lift-off method for pixelization of solution-processed materials and demonstrated its application in patterning perovskite quantum dot pixels, 10 µm in diameter, to construct a static micro-display. In this report, we present further development of this method, and demonstrate high-resolution patterning (~1 µm diameter), full-scale processing on 100 mm wafer, and multi-color integration of two different varieties of quantum dots. Perovskite and cadmium-selenide quantum dots were adopted for the experimentation, but the method can be applied to other types of solution-processed materials. We also show the viability of this method for constructing high-resolution micro-arrays of quantum dot color-convertors by fabricating patterned films directly on top of a blue gallium-nitride LED substrate. The green perovskite quantum dots used for fabrication are synthesized and prepared by our research group via room temperature ligand-assisted reprecipitation method, and these synthesized quantum dots have a photoluminescent quantum yield of 93.6% and full-width half-maximum emission linewidth less than 20 nm. Our results demonstrate the viability of this method for use in scalable manufacturing of high-resolution micro-displays. 

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4. Development of Quantum Dots Nanosensors for Heavy Metals Detection.

   Bailon-Ruiz, Sonia J; Cedeño-Mattei, Yarilyn (April 2024, Ceiba)

   This study demonstrates the potential application of polyethyleneimine (PEI)-modified quantum dots for sensing heavy metals, specifically copper ions, in aqueous matrices. Quantum dots were synthesized in aqueous phase, revealing a spherical morphology, a size of less than 5 nm, and a face-centered cubic crystalline structure. The presence of PEI on the quantum dots' surface significantly enhanced their photoluminescence within the range of 400 nm to 650 nm. To assess the sensor capabilities of PEI-capped quantum dots, two copper precursors (CuSO4 and CuNO3) were utilized at concentrations ranging from 0 ppm to 38 ppm. A systematic decrease in fluorescence intensity with increasing copper concentration was observed, establishing a quantitative relationship. These findings underscore the potential of PEI-modified quantum dots as efficient and selective sensors for copper ions. The concentration-dependent response in fluorescence intensity reflects the sensitivity of the system, suggesting promising applications in the field of heavy metal detection. 

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5. A Universal High‐Resolution Patterning Technology for Quantum Dot Color Converters in Micro‐LED Displays

   https://doi.org/10.1002/sdtp.17469  

   Velpugonda, John Leo; Yerich, Matthew; Johnson, Rose; Keeler, Ethan G; Lin, Lih Y (June 2024, SID Symposium Digest of Technical Papers)

   We report a photolithography‐based technology for patterning quantum dot color converters for micro‐LED displays. A patterning resolution of ~1 µm is achieved. The method can be applied to any color converter materials. Integration of perovskite quantum dots and CdSe/ZnS quantum dots is demonstrated to show the versatility of the technology. 

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