Reversible photodoping of TiO2 nanoparticles

Urmas Joost, Andris Sutka, Marek Oja, Krisjanis Smits, Nicola Doebelin, Ardi Loot, Martin Järvekülg, Mika Hirsimäki, Mika Valden, Ergo Nommiste

    Research output: Contribution to journalArticleScientificpeer-review

    23 Citations (Scopus)
    14 Downloads (Pure)


    Observations on strong photochromic effect of crystalline TiO2 quantum dots (mean size ≈ 4 nm) are presented. The synthesized quantum dots consist of irregularly shaped anatase TiO2 nanoparticles (NPs) and are dispersed in butanol (8 % by mass). Obtained NPs exhibit a dramatic photo-response to UV light, enabling effective transmittance modula-tion of in a broad wavelength range extending from visible to near-infrared region, and even the thermal black body radiation regime beyond 10 μm. The exceptional photo-response is attributed to hole-scavenging by butanol, TiO2 self-reduction, injection of electrons to the conduction band, and consequent localized surface plasmon resonances in NPs. Observed optical effect is reversible and the initial high transmittance state can be restored simply by exposing the NPs to air. Applied NP synthesis route is economic and can be easily scaled for applications such as smart window technol-ogies.
    Original languageEnglish
    Pages (from-to)8968-8974
    JournalChemistry of Materials
    Issue number24
    Early online date10 Dec 2018
    Publication statusPublished - 26 Dec 2018
    Publication typeA1 Journal article-refereed


    • tio2
    • nano
    • nanoparticle
    • photochromic
    • anatase
    • light
    • photonics
    • functional

    Publication forum classification

    • Publication forum level 3

    ASJC Scopus subject areas

    • Inorganic Chemistry
    • Materials Chemistry
    • Surfaces and Interfaces
    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics


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