(387b) Reversible On/Off Modulation of Photoluminescence from TiO2/CsPbBr3 Using Redox Clusters

Reversible
On/Off Modulation of Photoluminescence from TiO₂/CsPbBr₃
Using Redox Clusters

Azzah
Dyah Pramata, Yuji Akaishi, Armando T. Quitain, Tetsuya Kida

Abstract:

Lead halide perovskite quantum dots
(QDs) gained considerable attention owing to the excellent luminescent
properties. Here, we focus on modulation of the the
photoluminescence (PL) emission of perovskite QDs by coupling them with a redox
cluster of polyoxometalates (POMs). The stability of QDs was improved by TiO₂
coating. The as-prepared TiO₂/CsPbBr₃ QDs emits green
emission at green emission peaking at 522 nm with the full width at half
maximum (FWHM) of 18 nm and the quantum yield (QY) was 54.1%. The bandgap of
TiO₂/CsPbBr₃ QDs was 2.24 eV with the size 21.3 nm in
orthorhombic phase. We studied photoinduced electron transfer (PET) from the
TiO₂/CsPbBr₃ QDs to (Bu₄N)₄[W₁₀O₃₂]
(tetrakis(tetrabutylammonium)decatungstate) under
visible light irradiation. UV-vis absorbance, PL, and PL lifetime measurements
indicate that PET efficiently took place from the QDs to the POM. The exposure
of visible light excites and injects photogenerated electrons into POMs to
produce one-electron reduced POMs (POM^–), prompted the PL quenching.
The POM^– was easily oxidized by atmospheric oxygen, leading to the
PL recovery. The modulation process was repeated up to 12 cycles with PL
recovery above 80%. The results demonstrate the promising feature of the
QDs/POM system for applications optical memories, biosensing and photocatalytic
devices.

Keywords:
lead halide perovskite, quantum dots, On/Off switching, photoluminescence,
polyoxometalate