Tunable White‐Light Emission from Conjugated Polymer‐Di‐Ureasil Materials

Abstract

Conjugated polymer (CP)‐di‐ureasil composite materials displaying a tunable emission color from blue to yellow through white have been prepared using a simple sol–gel processing method. The tunability of the emission color arises from a combination of energy transfer between the di‐ureasil and the CP dopant and the excitation wavelength dependence of the di‐ureasil emission. Incorporation of the CP does not adversely affect the bulk or local structure of the di‐ureasil, enabling retention of the structural and mechanical properties of the host. Furthermore, CP‐di‐ureasils display superior thermal and photostability compared to the parent CPs. Thermogravimetric analysis shows that the onset of thermal decomposition can be increased by up to 130 °C for CP‐di‐ureasils, while photostability studies reveal a significant decrease in the extent of photodegradation. Steady‐state photoluminescence spectroscopy and picosecond time‐resolved emission studies indicate that the observed tunable emission arises as a consequence of incomplete energy transfer between the di‐ureasil and the CP dopant, resulting in emission from both species on direct excitation of the di‐ureasil matrix. The facile synthetic approach and tunable emission demonstrate that CP‐di‐ureasils are a highly promising route to white‐light‐emitters that simultaneously improve the stability and reduce the complexity of CP‐based multilayer device architectures.

Targeted design leads to tunable photoluminescence from perylene dicarboxdiimide–poly(oxyalkylene)/siloxane hybrids for luminescent solar concentrators

“…Moreover, for low dopant concentrations, it can be difficult to spectroscopically resolve the specific contribution of the dopant molecule from the ureasil host matrix. 28,34 The PXRD patterns for all samples exhibit a primary band at 19.5-21.11, with a shoulder at 12.2-13.51, which is typical of these amorphous materials (Fig. S7, ESI †).…”

“…In this context, a host material which is itself an organic-inorganic hybrid material may be preferable. The ureasils, a family of Class II hybrids, have attracted considerable attention as functional hosts for diverse optical applications including solid-state electrochromic devices, 26 components of full-colour displays 27,28 and as optical waveguides. 29,30 Ureasils are comprised of a siliceous skeleton that is chemically-grafted to poly(oxyalkylene) chains via urea [NHC(QO)HN] bridges.…”

“…29,30 Ureasils are comprised of a siliceous skeleton that is chemically-grafted to poly(oxyalkylene) chains via urea [NHC(QO)HN] bridges. They are intrinsically photoluminescent and have been frequently used as an active host for non-grafted lanthanide ions/complexes, 31,32 molecular dyes 33 and more recently p-conjugated polymers, 28,34 in which the excitation wavelength dependence of the ureasil emission is used to tune the extent of energy transfer between the host and the dopant. Ureasils can be processed as transparent free-standing monoliths or as thin films or coatings, and exhibit relatively high refractive indices (B1.49).…”

Ureasil organic–inorganic hybrids as photoactive waveguides for conjugated polyelectrolyte luminescent solar concentrators

“…[30][31][32][33] Ureasils are comprised of a siliceous skeleton that is chemically grafted to poly(alkylene oxide) chains through urea cross-linkages. In addition to satisfying the primary requirements of the waveguide (large optical window in UV/visible region, refractive index n~1.5), ureasils are intrinsically photoluminescent and can function as active hosts to tune the emission from luminescent dopants such as conjugated polymers, 34,35 organic dyes 33,36 and lanthanide complexes 30 through energy transfer. Their facile sol-gel synthesis facilitates the controlled placement of luminophores within the ureasil framework via covalent grafting to the siliceous backbone, which can be used to both inhibit aggregation 36 and/or promote specific packing.…”

Polyurethanes prepared from cyclocarbonated broccoli seed oil (PUcc): New biobased organic matrices for incorporation of phosphorescent metal nanocluster

“…Figure (a) presents the emission spectra observed by irradiating samples at 350 nm. Pure m‐XDA PUcc emits broadly in the blue region with a maximum centred at around 450 nm that is typical of urea moieties emission embedded in polymer . Cs 2 [Mo 6 I 8 (OCOC 2 F 5 ) 6 ] and (4‐amino, N ‐ethylpyridinium) 2 Mo 6 I 8 (C 2 F 5 COO) 6 present the same emission maximum centred at around 650 nm while once integrated in PUcc, this maximum is slightly red‐shifted to 680 nm.…”