194
N. Tamai and S. Masuo
quantum-confined system, CdSe NPLs with quantum well structure, shows a rapid
intraband relaxation (60–70 fs) due to efficient phonon emission and weak electronhole coupling, in which the carrier extraction from higher excited states is not so
efficient. 3D quantum-confined system, CdSe QDs, shows a phonon bottle neck and
strong electron-hole coupling, which is suitable to extract the hot carrier from higher
excited states. The wavefunction penetration leading to the strong electronic coupling
strength between CdSe QDs and Au NPs plays an important role for ultrafast electron
transfer. In addition, the manipulation of single and multiexcitons of a single QD was
demonstrated by using plasmonic nanostructures or metallic nanostructures (MNSs)
based on AFM and single particle spectroscopy. The electromagnetic enhancement
of absorption and luminescence of a single QD and energy transfer quenching by
MNSs are key factors to understand the strong distance dependence between a single
QD and a MNS.
Acknowledgements we deeply appreciate Professors K. Sasaki, T. Teranishi, H. Fujiwara,
R. Sato, Drs T. Okuhata, T. Katayama, and L. Wang for their collaboration. The present work
was supported by JSPS KAKENHI Grant numbers JP17H05254, 26390023 and 26107005 in
grant-in-aid for Scientific Research on Innovative Areas “Photosynergetics.”
References
1. Klimov VI (2000) Optical nonlinearities and ultrafast carrier dynamics in semiconductor
nanocrystals. J Phys Chem B 104:6112–6123
2. Schaller RD, Klimov VI (2004) High efficiency carrier multiplication in PbSe nanocrystals:
implications for solar energy conversion. Phys Rev Lett 92:186601
3. Kobayashi Y, Udagawa T, Tamai N (2009) Carrier multiplication in CdTe quantum dots by
single—photon timing spectroscopy. Chem Lett 38:830–831
4. McGuire JA, Joo J, Pietryga JM, Schaller RD, Klimov VI (2008) New aspects of carrier
multiplication in semiconductor nanocrystals. Acc Chem Res 41:1810–1819
5. Klimov VI (2007) Spectral and dynamical properties of multiexcitons in semiconductor
nanocrystals. Ann Rev Phys Chem 58:635–673
6. Kambhampati P (2011) Hot exciton relaxation dynamics in semiconductor quantum dots:
radiationless transitions on the nanoscale. J Phys Chem C 115:22089–22109
7. Kambhampati P (2011) Unraveling the structure and dynamics of excitons in semiconductor
quantum dots. Acc Chem Res 44:1–13
8. Cooney RR, Sewall SL, Dias EA, Sagar DM, Anderson KEH, Kambhampati P (2007) Unified
picture of electron and hole relaxation pathways in semiconductor quantum dots. Phys Rev B
75:245311
9. Guyot − Sionnest P, Wehrenberg B, Yu D (2005) Intraband relaxation in CdSe nanocrystals
and the strong influence of the surface ligands. J Chem Phys 123:074709
10. Okuhata T, Tamai N (2016) Face-dependent electron transfer in CdSe nanoplatelet-methyl
viologen complexes. J Phys Chem C 120:17052–17059
11. Shockley W, Queisser HJ (1961) Detailed balance limit of efficiency of p–n junction solar cells.
J Appl Phys 32:510–519
12. Ross RT, Nozik AJ (1982) Efficiency of hot–carrier solar energy converters. J Appl Phys
53:3813–3818
13. Kobayashi Y, Pan L, Tamai N (2009) Effects of size and capping reagents on biexciton auger
recombination dynamics of CdTe quantum dots. J Phys Chem C 113:11783–11789
N. Tamai and S. Masuo
quantum-confined system, CdSe NPLs with quantum well structure, shows a rapid
intraband relaxation (60–70 fs) due to efficient phonon emission and weak electronhole coupling, in which the carrier extraction from higher excited states is not so
efficient. 3D quantum-confined system, CdSe QDs, shows a phonon bottle neck and
strong electron-hole coupling, which is suitable to extract the hot carrier from higher
excited states. The wavefunction penetration leading to the strong electronic coupling
strength between CdSe QDs and Au NPs plays an important role for ultrafast electron
transfer. In addition, the manipulation of single and multiexcitons of a single QD was
demonstrated by using plasmonic nanostructures or metallic nanostructures (MNSs)
based on AFM and single particle spectroscopy. The electromagnetic enhancement
of absorption and luminescence of a single QD and energy transfer quenching by
MNSs are key factors to understand the strong distance dependence between a single
QD and a MNS.
Acknowledgements we deeply appreciate Professors K. Sasaki, T. Teranishi, H. Fujiwara,
R. Sato, Drs T. Okuhata, T. Katayama, and L. Wang for their collaboration. The present work
was supported by JSPS KAKENHI Grant numbers JP17H05254, 26390023 and 26107005 in
grant-in-aid for Scientific Research on Innovative Areas “Photosynergetics.”
References
1. Klimov VI (2000) Optical nonlinearities and ultrafast carrier dynamics in semiconductor
nanocrystals. J Phys Chem B 104:6112–6123
2. Schaller RD, Klimov VI (2004) High efficiency carrier multiplication in PbSe nanocrystals:
implications for solar energy conversion. Phys Rev Lett 92:186601
3. Kobayashi Y, Udagawa T, Tamai N (2009) Carrier multiplication in CdTe quantum dots by
single—photon timing spectroscopy. Chem Lett 38:830–831
4. McGuire JA, Joo J, Pietryga JM, Schaller RD, Klimov VI (2008) New aspects of carrier
multiplication in semiconductor nanocrystals. Acc Chem Res 41:1810–1819
5. Klimov VI (2007) Spectral and dynamical properties of multiexcitons in semiconductor
nanocrystals. Ann Rev Phys Chem 58:635–673
6. Kambhampati P (2011) Hot exciton relaxation dynamics in semiconductor quantum dots:
radiationless transitions on the nanoscale. J Phys Chem C 115:22089–22109
7. Kambhampati P (2011) Unraveling the structure and dynamics of excitons in semiconductor
quantum dots. Acc Chem Res 44:1–13
8. Cooney RR, Sewall SL, Dias EA, Sagar DM, Anderson KEH, Kambhampati P (2007) Unified
picture of electron and hole relaxation pathways in semiconductor quantum dots. Phys Rev B
75:245311
9. Guyot − Sionnest P, Wehrenberg B, Yu D (2005) Intraband relaxation in CdSe nanocrystals
and the strong influence of the surface ligands. J Chem Phys 123:074709
10. Okuhata T, Tamai N (2016) Face-dependent electron transfer in CdSe nanoplatelet-methyl
viologen complexes. J Phys Chem C 120:17052–17059
11. Shockley W, Queisser HJ (1961) Detailed balance limit of efficiency of p–n junction solar cells.
J Appl Phys 32:510–519
12. Ross RT, Nozik AJ (1982) Efficiency of hot–carrier solar energy converters. J Appl Phys
53:3813–3818
13. Kobayashi Y, Pan L, Tamai N (2009) Effects of size and capping reagents on biexciton auger
recombination dynamics of CdTe quantum dots. J Phys Chem C 113:11783–11789