Browsing by Author "Schellhammer, Sebastian"

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  • ItemOpen Access
    Original research data of "Immediate Organic Room-Temperature Phosphorescence in Programmable Luminescent Tags Enabled by Oxygen-Free Fabrication"
    (Technische Universität Dresden, 2026-07-08) Winkler, Lucy; Schellhammer, Sebastian; Reineke, Sebastian
    Original research data to the following paper: Programmable luminescent tags (PLTs) exploit the oxygen sensitivity of room-temperature phosphorescence (RTP) from organic emitters to enable reversible information storage. In conventional PLTs, phosphorescence is initially quenched by oxygen incorporated during ambient processing. Upon UV irradiation, oxygen is photochemically consumed, activating RTP emission. While a single-use application is already commercially exploited in UV sensors, reusability is prevented by decreasing activation dose and RTP intensity over multiple activation cycles, which had previously been attributed to oxygen trapped during the fabrication process. Here, we introduce an oxygen-free fabrication workflow that enables direct control of the oxygen content in PLTs and thereby allows systematic investigation of its role in the activation process. It is demonstrated that oxygen can diffuse out of the active layer under oxygen-free conditions, resulting in oxygen-free devices with immediate RTP emission. A comparison of the reusability of oxygen-free and conventional PLTs reveals similar behavior, indicating that photodegradation rather than trapped oxygen dominates long-term performance. In addition, thermal preconditioning of oxygen-free PLTs enables regulated oxygen re-entry, allowing the activation dose to be tuned without modifying the material composition or device architecture. These findings clarify degradation processes in PLTs and establish a general framework for activation-tuned RTP in photonic devices.
  • ItemOpen Access
    Original research data of "Tunable-Threshold UV Dosimetry with Programmable Luminescent Tags via Oxygen-Mediated Room-Temperature Phosphorescence"
    (Technische Universität Dresden, 2026-05-19) Achenbach, Tim; Will, Paul-Anton; Schellhammer, Sebastian; Reineke, Sebastian
    Original research data to the following paper: Accurate monitoring of UV radiation is critical across numerous disciplines, yet bridging the gap between complex electronic devices and ambiguous, gradual colorimetric indicators remains challenging. Addressing this challenge, a novel approach for a customizable, purely organic UV threshold dosimeter based on oxygen-mediated room-temperature phosphorescence (RTP) is presented. The active layer comprises a purely organic emitter (BP-2TA) dispersed in a poly(methyl methacrylate) (PMMA) host, protected by a polyvinyl alcohol layer. Upon UV irradiation, photochemical oxygen consumption yields a high-contrast, sharp turn-on of the emitter’s phosphorescent emission once a specific cumulative UV dose is reached. This activation depends strictly on the cumulative dose rather than irradiation intensity and is systematically tunable by adjusting the emitter concentration. A comprehensive physical model is introduced that describes the wavelength and thickness dependencies, revealing a thin-film regime where the activation dose becomes independent of the active layer thickness. Supported by shelf-life stability tests, these findings, alongside the proposed operational modes, establish the RTP-based sensors as robust UV dosimeters that could be easily integrated into production processes.