168
K. Kamada et al.
successfully demonstrated. The quantum efficiency of each elementary process was
elucidated by various spectroscopies, including time-resolved UC emission and transient absorption spectroscopies. Very fast TET was found in solid, and the bottleneck
step of the total QY was clarified. Moreover, a novel approach was tested by bonding
sensitizer on a solid surface of nanopore to prevent the aggregation of sensitizer.
The non-radiative deactivation of the triplet was suppressed by fixing on the surface.
TET from sensitizer on the solid surface to emitter diffusing in solvent was found to
occur, leading TTA-UC.
These results are open a new page in the usage of the excitation energy of triplets,
especially in solid medium. The importance of manipulating triplets and the efficient
usage in solid will be increased in the future. These works will be a part of the
foundation in further studies.
Acknowledgements We deeply appreciate to Professors M. Nakano, Y. Kitagawa, R. Kishi, K.
Kobayashi, S. Hirata, M. Vacha, H. Sotome, H. Miyasaka, D. Kuzuhara, H. Yamada for their
collaboration. The present work was supported by JSPS KAKENHI Grant Number 26107004,
Grant-in-Aid for Scientific Research on Innovative Areas “Photosynergetics.”
References
1. Ito S, Nagami T, Nakano M (2018) Molecular design for efficient singlet fission. J Photochem
Photobiol, C 34:85–120
2. Ito S, Nagami T, Nakano M (2017) Singlet fission in pancake-bonded systems. Phys Chem
Chem Phys 19:5737–5745
3. Ito S, Nagami T, Nakano M (2017) Rational design of doubly-bridged chromophores for singlet
fission and triplet–triplet annihilation. RSC Adv 7:34830–34845
4. Nagami T, Ito S, Kubo T, Nakano M (2017) Intermolecular packing effects on singlet fission
in oligorylene dimers. ACS Omega 2:5095–5103
5. Ito S, Nagami T, Nakano M (2015) Density analysis of intra- and intermolecular vibronic
couplings toward bath engineering for singlet fission. J Phys Chem Lett 6:4972–4977
6. Nakano M, Ito S, Nagami T, Kitagawa Y, Kubo T (2016) Quantum master equation approach
to singlet fission dynamics of realistic/artificial pentacene dimer models: relative relaxation
factor analysis. J Phys Chem C 120:22803–22815
7. Nakano M (2019) Quantum master equation approach to singlet fission dynamics in pentacene
ring-shaped aggregate models. J Chem Phys 150: 234305 (18 page)
8. Garoni E, Zirzlmeier J, Basel BS, Hetzer C, Kamada K, Guldi DM, Tykwinski RR (2017)
Two-photon absorption in pentacene dimers: the importance of the tether using upconversion
as an indirect route to singlet fission. J Am Chem Soc 139:14017–14020
9. Birks JB (1970) Photophysics of aromatic molecule. Wiley, London
10. Parker CA, Hatchard CG (1962) Sensitized anti-Stokes delayed fluorescence. Proc Chem Soc
386–387
11. Islangulov RR, Kozlov DV, Castellano FN (2005) Low power upconversion using MLCT
sensitizers. Chem Commun 1:3776–3778
12. Kamada, K, Sakagami Y, Mizokuro T, Fujiwara Y, Kobayashi K, Narushima K, Hirata S,
Vacha M (2017) Efficient triplet–triplet annihilation upconversion in binary crystalline solids
fabricated by solution casting and operated in air. Mater Horiz 4:83–87; ibid. (2018) 5:1219
13. Murakami Y (2011) Photochemical photon upconverters with ionic liquids. Chem Phys Lett
516:56–61
K. Kamada et al.
successfully demonstrated. The quantum efficiency of each elementary process was
elucidated by various spectroscopies, including time-resolved UC emission and transient absorption spectroscopies. Very fast TET was found in solid, and the bottleneck
step of the total QY was clarified. Moreover, a novel approach was tested by bonding
sensitizer on a solid surface of nanopore to prevent the aggregation of sensitizer.
The non-radiative deactivation of the triplet was suppressed by fixing on the surface.
TET from sensitizer on the solid surface to emitter diffusing in solvent was found to
occur, leading TTA-UC.
These results are open a new page in the usage of the excitation energy of triplets,
especially in solid medium. The importance of manipulating triplets and the efficient
usage in solid will be increased in the future. These works will be a part of the
foundation in further studies.
Acknowledgements We deeply appreciate to Professors M. Nakano, Y. Kitagawa, R. Kishi, K.
Kobayashi, S. Hirata, M. Vacha, H. Sotome, H. Miyasaka, D. Kuzuhara, H. Yamada for their
collaboration. The present work was supported by JSPS KAKENHI Grant Number 26107004,
Grant-in-Aid for Scientific Research on Innovative Areas “Photosynergetics.”
References
1. Ito S, Nagami T, Nakano M (2018) Molecular design for efficient singlet fission. J Photochem
Photobiol, C 34:85–120
2. Ito S, Nagami T, Nakano M (2017) Singlet fission in pancake-bonded systems. Phys Chem
Chem Phys 19:5737–5745
3. Ito S, Nagami T, Nakano M (2017) Rational design of doubly-bridged chromophores for singlet
fission and triplet–triplet annihilation. RSC Adv 7:34830–34845
4. Nagami T, Ito S, Kubo T, Nakano M (2017) Intermolecular packing effects on singlet fission
in oligorylene dimers. ACS Omega 2:5095–5103
5. Ito S, Nagami T, Nakano M (2015) Density analysis of intra- and intermolecular vibronic
couplings toward bath engineering for singlet fission. J Phys Chem Lett 6:4972–4977
6. Nakano M, Ito S, Nagami T, Kitagawa Y, Kubo T (2016) Quantum master equation approach
to singlet fission dynamics of realistic/artificial pentacene dimer models: relative relaxation
factor analysis. J Phys Chem C 120:22803–22815
7. Nakano M (2019) Quantum master equation approach to singlet fission dynamics in pentacene
ring-shaped aggregate models. J Chem Phys 150: 234305 (18 page)
8. Garoni E, Zirzlmeier J, Basel BS, Hetzer C, Kamada K, Guldi DM, Tykwinski RR (2017)
Two-photon absorption in pentacene dimers: the importance of the tether using upconversion
as an indirect route to singlet fission. J Am Chem Soc 139:14017–14020
9. Birks JB (1970) Photophysics of aromatic molecule. Wiley, London
10. Parker CA, Hatchard CG (1962) Sensitized anti-Stokes delayed fluorescence. Proc Chem Soc
386–387
11. Islangulov RR, Kozlov DV, Castellano FN (2005) Low power upconversion using MLCT
sensitizers. Chem Commun 1:3776–3778
12. Kamada, K, Sakagami Y, Mizokuro T, Fujiwara Y, Kobayashi K, Narushima K, Hirata S,
Vacha M (2017) Efficient triplet–triplet annihilation upconversion in binary crystalline solids
fabricated by solution casting and operated in air. Mater Horiz 4:83–87; ibid. (2018) 5:1219
13. Murakami Y (2011) Photochemical photon upconverters with ionic liquids. Chem Phys Lett
516:56–61