TY - JOUR
T1 - Employing Core-Shell Quantum Dots as Triplet Sensitizers for Photon Upconversion
AU - Okumura, Keisuke
AU - Mase, Kazuma
AU - Yanai, Nobuhiro
AU - Kimizuka, Nobuo
N1 - Funding Information:
This work was partially supported by a Grants-in-Aid for Scientific Research (S) (25220805), a Grants-in-Aid for Young Scientists (B) (26810036), a Grant-in-Aid for Scientific Research on Innovative Area (16H00844) from the Ministry of Education, Culture, Sports, Science and Technology of Japan, and the JSPS-NSF International Collaborations in Chemistry (ICC) program.
Publisher Copyright:
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - A new family of surface-functionalized CdSe/ZnS core-shell quantum dots (csQD) has been developed, which work as triplet sensitizers for triplet-triplet annihilation-based photon upconversion (TTA-UC). The surface modification of csQD with acceptor molecules plays a key role in the efficient relay of the excited energy of csQD to emitter molecules in the bulk solution, where the generated emitter triplets undergo triplet-triplet annihilation that leads to photon upconversion. Interestingly, improved UC properties were achieved with the core-shell QDs compared with core-only CdSe QDs (cQD). The threshold excitation intensity, which is defined as the necessary irradiance to achieve efficient TTA process, decreases by more than a factor of four. Furthermore, the total UC quantum yield is enhanced more than 50-fold. These enhancements should be derived from better optical properties of csQD, in which the non-radiative surface recombination sites are passivated by the shell layer with wider bandgap.
AB - A new family of surface-functionalized CdSe/ZnS core-shell quantum dots (csQD) has been developed, which work as triplet sensitizers for triplet-triplet annihilation-based photon upconversion (TTA-UC). The surface modification of csQD with acceptor molecules plays a key role in the efficient relay of the excited energy of csQD to emitter molecules in the bulk solution, where the generated emitter triplets undergo triplet-triplet annihilation that leads to photon upconversion. Interestingly, improved UC properties were achieved with the core-shell QDs compared with core-only CdSe QDs (cQD). The threshold excitation intensity, which is defined as the necessary irradiance to achieve efficient TTA process, decreases by more than a factor of four. Furthermore, the total UC quantum yield is enhanced more than 50-fold. These enhancements should be derived from better optical properties of csQD, in which the non-radiative surface recombination sites are passivated by the shell layer with wider bandgap.
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U2 - 10.1002/chem.201600998
DO - 10.1002/chem.201600998
M3 - Article
AN - SCOPUS:84992303256
SN - 0947-6539
VL - 22
SP - 7721
EP - 7726
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 23
ER -