Light is another environmental stimulus that can cause fluorescence change in CPs. UV
irradiation is a powerful energy source for photochemical reactions and an effective tool for RI
modulation and formation of photopatterns. Modulation of refractivity is a crucial technology in
optical data storage, and hence polymeric materials with tunable refractive indices are of great
interest. For example, polymeric sulfur-rich PVS 23c with silole moieties shows RI of
1.74401.6848 in the wavelength range of 600-1700 nm,Error! Bookmark not defined. whose values are
much higher than some commercial polymers [67]. It crosslinks in the presence of UV irradiation,
which has lowered its electronic conjugation and backbone’s polarizability as well as the RI
values. As illustrated in Figure 2C, after UV irradiation for 15 min, its RI drops by 0.1221.
Moreover, the UV-promoted photo-oxidation allows facile fabrication of well-resolved fluorescent
patterns. By UV irradiation of a uniform film of 23c coated on a silica wafer through a designed
nanoscale mask, the emission of the exposed parts (black lines) is photo-bleached, while that of
the covered areas remains unaltered. A fluorescent pattern with a high contrast is thus generated
(Figure 2D).
Light is another environmental stimulus that can cause fluorescence change in CPs. UVirradiation is a powerful energy source for photochemical reactions and an effective tool for RImodulation and formation of photopatterns. Modulation of refractivity is a crucial technology inoptical data storage, and hence polymeric materials with tunable refractive indices are of greatinterest. For example, polymeric sulfur-rich PVS 23c with silole moieties shows RI of1.74401.6848 in the wavelength range of 600-1700 nm,Error! Bookmark not defined. whose values aremuch higher than some commercial polymers [67]. It crosslinks in the presence of UV irradiation,which has lowered its electronic conjugation and backbone’s polarizability as well as the RIvalues. As illustrated in Figure 2C, after UV irradiation for 15 min, its RI drops by 0.1221.Moreover, the UV-promoted photo-oxidation allows facile fabrication of well-resolved fluorescentpatterns. By UV irradiation of a uniform film of 23c coated on a silica wafer through a designednanoscale mask, the emission of the exposed parts (black lines) is photo-bleached, while that ofthe covered areas remains unaltered. A fluorescent pattern with a high contrast is thus generated(Figure 2D).
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