17 Synergetic Photon Upconversion Realized by a Controlled …
297
17.5 Conclusion and Future Perspective
Further studies are certainly needed but a unique cylindrical structure and synergetic dynamism of HAB derivatives were successfully utilized for better TTA-UC
processes, where the toroidal interaction between the peripheral aromatic rings plays
crucial roles. Thus, aligning multiple chromophores as a cyclic array, like in HAB
derivatives exemplified herein, provides a positive synergetic effect for the efficient TTA and such approach was clearly established as a novel design principle
for effective annihilator for TTA process.
Additional synergistic effects have been also demonstrated in the literature for the
better TTA-UC. For instance, by simply employing multiple (and different) acceptors,
the UC quantum yield being significantly improved from the single acceptor system
[58]. It has been also reported that the TTA efficiency was improved by using a
multi-component acceptor, in which the chromophore of a lower triplet state energy
and the chromophore better suited in terms of the corresponding singlet state energy
are directly connected [59]. Such an apparently simple modification may provide
additional opportunity to further advance the TTA-UC efficiency that should be
more exploited in the future design of sensitizer and/or acceptor chromophores.
Acknowledgements Financial supports by Grant-in-Aids for Scientific Research, Challenging
Exploratory Research, Promotion of Joint International Research (Fostering Joint International Research), and on Innovative Areas “Photosynergetics” (Grant Numbers JP15H03779,
JP15K13642, JP16H06041, JP16KK0111, JP17H05261, JP18K19077, and JP18H01964) from
JSPS, by the Asahi Glass Foundation, by the Murata Science Foundation, and by the Research
Program of Five-star Alliance in NJRC Mater. & Dev. are greatly acknowledged.
References
1. Zhu X, Su Q, Feng W, Li F (2017) Anti-Stokes shift luminescent materials for bio-applications.
Chem Soc Rev 46:1025–1039. https://doi.org/10.1039/C6CS00415F
2. Ye C, Zhou L, Wang X, Liang Z (2016) Photon upconversion: from two-photon absorption
(TPA) to triplet-triplet annihilation (TTA). Phys Chem Chem Phys 18:10818–10835. https://
doi.org/10.1039/C5CP07296D
3. Zhou J, Liu Q, Feng W, Sun Y, Li F (2015) Upconversion luminescent materials: advances and
applications. Chem Rev 115:395–465. https://doi.org/10.1021/cr400478f
4. Singh-Rachford TN, Castellano FN (2010) Photon upconversion based on sensitized triplettriplet annihilation. Coord Chem Rev 254:2560–2573. https://doi.org/10.1016/j.ccr.2010.
01.003
5. Zhao J, Ji S, Guo H (2011) Triplet-triplet annihilation based upconversion: from triplet sensitizers and triplet acceptors to upconversion quantum yields. RSC Adv 1:937–950. https://doi.
org/10.1039/C1RA00469G
6. Parker CA, Hatchard CG (1962) Delayed fluorescence from solutions of anthracene and
phenanthrene. Proc Chem Soc 147. http://dx.doi.org/10.1039/PS9620000133
7. Parker CA, Hatchard CG (1962) Sensitised anti-Stokes delayed fluorescence. Proc Chem Soc
386–387. https://doi.org/10.1039/PS9620000373
297
17.5 Conclusion and Future Perspective
Further studies are certainly needed but a unique cylindrical structure and synergetic dynamism of HAB derivatives were successfully utilized for better TTA-UC
processes, where the toroidal interaction between the peripheral aromatic rings plays
crucial roles. Thus, aligning multiple chromophores as a cyclic array, like in HAB
derivatives exemplified herein, provides a positive synergetic effect for the efficient TTA and such approach was clearly established as a novel design principle
for effective annihilator for TTA process.
Additional synergistic effects have been also demonstrated in the literature for the
better TTA-UC. For instance, by simply employing multiple (and different) acceptors,
the UC quantum yield being significantly improved from the single acceptor system
[58]. It has been also reported that the TTA efficiency was improved by using a
multi-component acceptor, in which the chromophore of a lower triplet state energy
and the chromophore better suited in terms of the corresponding singlet state energy
are directly connected [59]. Such an apparently simple modification may provide
additional opportunity to further advance the TTA-UC efficiency that should be
more exploited in the future design of sensitizer and/or acceptor chromophores.
Acknowledgements Financial supports by Grant-in-Aids for Scientific Research, Challenging
Exploratory Research, Promotion of Joint International Research (Fostering Joint International Research), and on Innovative Areas “Photosynergetics” (Grant Numbers JP15H03779,
JP15K13642, JP16H06041, JP16KK0111, JP17H05261, JP18K19077, and JP18H01964) from
JSPS, by the Asahi Glass Foundation, by the Murata Science Foundation, and by the Research
Program of Five-star Alliance in NJRC Mater. & Dev. are greatly acknowledged.
References
1. Zhu X, Su Q, Feng W, Li F (2017) Anti-Stokes shift luminescent materials for bio-applications.
Chem Soc Rev 46:1025–1039. https://doi.org/10.1039/C6CS00415F
2. Ye C, Zhou L, Wang X, Liang Z (2016) Photon upconversion: from two-photon absorption
(TPA) to triplet-triplet annihilation (TTA). Phys Chem Chem Phys 18:10818–10835. https://
doi.org/10.1039/C5CP07296D
3. Zhou J, Liu Q, Feng W, Sun Y, Li F (2015) Upconversion luminescent materials: advances and
applications. Chem Rev 115:395–465. https://doi.org/10.1021/cr400478f
4. Singh-Rachford TN, Castellano FN (2010) Photon upconversion based on sensitized triplettriplet annihilation. Coord Chem Rev 254:2560–2573. https://doi.org/10.1016/j.ccr.2010.
01.003
5. Zhao J, Ji S, Guo H (2011) Triplet-triplet annihilation based upconversion: from triplet sensitizers and triplet acceptors to upconversion quantum yields. RSC Adv 1:937–950. https://doi.
org/10.1039/C1RA00469G
6. Parker CA, Hatchard CG (1962) Delayed fluorescence from solutions of anthracene and
phenanthrene. Proc Chem Soc 147. http://dx.doi.org/10.1039/PS9620000133
7. Parker CA, Hatchard CG (1962) Sensitised anti-Stokes delayed fluorescence. Proc Chem Soc
386–387. https://doi.org/10.1039/PS9620000373