Browsing by Author "Pope J"

Now showing 1 - 2 of 2
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    Color Tunable Emission and Oxygen Sensing from a Discrete Europium−Pyrene Assembly
    (Wiley-VCH GmbH, 2023-08-14) O'Neil AT; Pope J; Harrison JA; Kitchen JA
    We report the synthesis of a new pyrene, dipicolinic acid-based ligand (L1H) and its corresponding multi-emissive and multifunctional europium complex [Eu(L1)3] that is capable of single component color switchable emission from red to blue and also white. At high concentration (10 mM) the single component system results in near pure white emission (CIE coordinates x,y=0.329, 0.324). Furthermore, the system showed ratiometric oxygen sensing with oxygen significantly quenching the pyrene centered emission but not the Eu3+ emission, resulting in an overall emission color change from blue to red on increasing oxygen content.
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    Ultraviolet-C Photoresponsivity Using Fabricated TiO2 Thin Films and Transimpedance-Amplifier-Based Test Setup
    (MDPI (Basel, Switzerland), 2022-11) Cadatal-Raduban M; Pope J; Olejníček J; Kohout M; Harrison JA; Hasan SMR; Torres ML; De Luca AC; Mourka A
    We report on fabricated titanium dioxide (TiO2) thin films along with a transimpedance amplifier (TIA) test setup as a photoconductivity detector (sensor) in the ultraviolet-C (UV-C) wavelength region, particularly at 260 nm. TiO2 thin films deposited on high-resistivity undoped silicon-substrate at thicknesses of 100, 500, and 1000 nm exhibited photoresponsivities of 81.6, 55.6, and 19.6 mA/W, respectively, at 30 V bias voltage. Despite improvements in the crystallinity of the thicker films, the decrease in photocurrent, photoconductivity, photoconductance, and photoresponsivity in thicker films is attributed to an increased number of defects. Varying the thickness of the film can, however, be leveraged to control the wavelength response of the detector. Future development of a chip-based portable UV-C detector using TiO2 thin films will open new opportunities for a wide range of applications.