Photoquenching-by-Photocharging, a Single Process-of-Failure of Oxygen-Exposed InP/ZnSe Quantum Dots

Robin R. Petit^a^,^b, Pieter Schiettecatte^c, Korneel Molkens^c, Matthias Minjauw^b, Eder A. Castillo-Ruiz^c, Hannes Van Avermaet^c, Luca Giordano^c, Andreas Werbrouck^b, Pieter Geiregat^c, Henk Vrielinck^d, Christophe Detavernier^b, Philippe F. Smet^a, Zeger Hens^c

^aDepartment of Solid State Sciences, LumiLab, Ghent University, 9000 Ghent, Belgium

^bDepartment of Solid State Sciences, CoCooN, Ghent University, 9000 Ghent, Belgium

^cDepartment of Chemistry, Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium

^dDepartment of Solid State Sciences, Defects in Semiconductors, Ghent University, 9000 Ghent, Belgium

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

D2 Quantum dots from III-V semiconductors – from synthesis to applications

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Zeger Hens and Ivan Infante

Oral, Robin R. Petit, presentation 226
Publication date: 15th December 2025

The synthesis of InP-based QDs has made great strides in recent years, with state-of-the-art core/shell strategies resulting in near-unity photoluminescence quantum yield (PLQY).[1] Ensuring reliability under working conditions is a shared challenge amongst emerging opto-electronic technologies, complicated by the fact that the fundamental chemical processes leading to performance deterioration remain poorly understood. In this work, we bridge the knowledge gap and identify a single process-of-failure that leads to photoluminescence (PL) quenching of InP-based QDs: InP/ZnSe/ZnS QDs and InP/ZnSe/Zn(Se, S)/ZnS QDs.

Using a home-built in situ PL setup,[2] we investigated the effect of different gas atmospheres and revealed that PL quenching is triggered under continuous illumination in an O₂-containing atmosphere, while straightforward oxidation of the QDs is ruled out by X-ray photoelectron spectroscopy (XPS). Instead, the PL quenching is directly correlated to the charging of the QDs, with femtosecond transient absorption spectroscopy (fs TAS) showing evidence of non-emissive trions after photoexcitation. Following illumination in air, the band-edge bleach decays more rapidly than after illumination in an inert atmosphere and is characterized by components with lifetimes of 133 ps and 5 ps, indicating a growing importance of non-radiative Auger processes. We sought to determine the radical species formed following the removal of the electron from the QD using electron paramagnetic resonance (EPR) spectroscopy, which confirmed the formation of superoxide and an alkoxyl-type radical. Gaining insight into this single process-of-failure is a necessary step to guide QD synthesis toward enhancing the reliability of devices using InP-based QDs for photoluminescent color conversion or electroluminescent light emission.

References:

[1] Van Avermaet, H.; Schiettecatte, P.; Hinz, S.; Giordano, L.; Ferrari, F.; Nayral, C.; Delpech, F.; Maultzsch, J.; Lange, H.; Hens, Z. Full-Spectrum InP-Based Quantum Dots with Near-Unity Photoluminescence Quantum Efficiency. ACS Nano 2022, 16 (6), 9701-9712.

[2] Kuhs, J.; Werbrouck, A.; Zawacka, N.; Drijvers, E.; Smet, P. F.; Hens, Z.; Detavernier, C. In Situ Photoluminescence of Colloidal Quantum Dots During Gas Exposure—The Role of Water and Reactive Atomic Layer Deposition Precursors. ACS Appl. Mater. Interfaces 2019, 11 (29), 26277-26287.

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