135
CD characteristics may be the first examples among the aggregation-induced chiroptical studies reported so far.
6.3.9 Optical Confinement Effect
During photosynthesis, incoherent circularly polarized (CP) light from the sun
helps in travel and delocalization of photoexcited energy in chiral chlorophyll
aggregates in the aqueous fluid in the chloroplasts. Inspired by this biosystem,
Nakano and Fujiki (2011) prepared polymer aggregates of three highly luminescent
helical polysilanes: 1-S, 2-S, and 2-R (Scheme 6.7). The 1-S aggregates showed
very strong CPL with g CPL = 0.7 at 330 nm with high quantum efficiency (Φ PL ) of
Fig. 6.9 (a) ORD and UV spectra (25.0 °C) and (b) CPL and PL spectra (26.4 °C) excited at
290 nm for 1-S (molecular weight (Mw) = 88,500 and polydispersity index (PDI = weight-average
apparent molecular weight (M w )/number-average apparent molecular weight (M n ) or molecular
weight distribution – MWD) =1.22) aggregates formed in THF/methanol (1.7/1.3(v/v)) using a
stirring speed of 800 rpm for (a, b) ([Si-repeating unit] = 6.25 × 10
–6 M). Reproduced with permission from Nakano and Fujiki (2011)
6 Circularly Polarized Luminescent Polymers: Emerging Materials for Photophysical…
CD characteristics may be the first examples among the aggregation-induced chiroptical studies reported so far.
6.3.9 Optical Confinement Effect
During photosynthesis, incoherent circularly polarized (CP) light from the sun
helps in travel and delocalization of photoexcited energy in chiral chlorophyll
aggregates in the aqueous fluid in the chloroplasts. Inspired by this biosystem,
Nakano and Fujiki (2011) prepared polymer aggregates of three highly luminescent
helical polysilanes: 1-S, 2-S, and 2-R (Scheme 6.7). The 1-S aggregates showed
very strong CPL with g CPL = 0.7 at 330 nm with high quantum efficiency (Φ PL ) of
Fig. 6.9 (a) ORD and UV spectra (25.0 °C) and (b) CPL and PL spectra (26.4 °C) excited at
290 nm for 1-S (molecular weight (Mw) = 88,500 and polydispersity index (PDI = weight-average
apparent molecular weight (M w )/number-average apparent molecular weight (M n ) or molecular
weight distribution – MWD) =1.22) aggregates formed in THF/methanol (1.7/1.3(v/v)) using a
stirring speed of 800 rpm for (a, b) ([Si-repeating unit] = 6.25 × 10
–6 M). Reproduced with permission from Nakano and Fujiki (2011)
6 Circularly Polarized Luminescent Polymers: Emerging Materials for Photophysical…