Influence of CdSe/ZnS Quantum Dots in the Polymerization Process and in the Grating Recording in Acrylate Materials

Abstract

The initiation step of the polymerization of acrylate materials is first studied in detail by UV-visible spectroscopy, showing the involvement of each species of the three-component photosensitizer. Then, the implementation of a combined holographic and physicochemical investigation approach is used to determine the influence of photoluminescent CdSe/ZnS quantum dots (QDs) in the photopolymerization and grating recording process in composites containing those QD nanoparticles. The fluorescence microscopy evidences the dynamic distribution profile of QDs due to their diffusion from the irradiated zones to the interface between the bright and the dark zones and, finally, their accumulation in nonirradiated zones. At the same time, the infrared spectroscopy shows that the presence of QDs provides a noticeable decrease of the polymerization rate, which favors the diffusion of the monomer and QDs. These two phenomena contribute to the enhancement of the refractive index modulation depth.

Photopolymerizable nanocomposite photonic materials and their holographic applications in light and neutron optics

“…On the other hand, CdZnS (4–7 nm in diameter) having a moderate quantum yield was able to be dispersed at the concentration of 20 wt% with appropriate reagents. Barichard et al [ 63 , 64 ] also investigated the photopolymerization process and volume holographic recording at 488 nm in NPCs incorporating CdSe/ZnS QDs (5.2 nm in diameter). It was found that the presence of QDs gave a noticeable decrease in the polymerization rate due to the trap of a co-initiator at the surface of QDs, facilitating the diffusion of monomer and QDs under inhomogeneous light illumination and thereby increasing to as large as at 0.5 wt% CdSe/ZnS QDs.…”

Physico-chemical role of CdSe/ZnS quantum dots in the photo-polymerization process of acrylate composite materials

“…Recently, we have been involved in the study of acrylate photopolymerizable composition that was doped with CdSe/ZnS quantum dots emitting at 620 nm (further named red QDs). 30,31 In a first step, we evidenced the counter-diffusion of QDs induced by a spatially nonuniform ''one line intensity'' exposition. 30 In a second step, we applied a combined holographic and physico-chemical approach, which allowed examining the influence of CdSe/ZnS QDs on the recording of gratings of very large spatial period (100 mm) and on the involved photopolymerization processes.…”

“…30 In a second step, we applied a combined holographic and physico-chemical approach, which allowed examining the influence of CdSe/ZnS QDs on the recording of gratings of very large spatial period (100 mm) and on the involved photopolymerization processes. 31 The fluorescence microscopy permitted us to follow the diffusion of QDs happening even in such large spatial scales. It pointed out that during the hologram recording, the QDs were first pushed (from high intensity zones) towards the interface between the bright and the dark zones of light and were then finally relocated inside the non-irradiated regions.…”

Effects of ZnO quantum dots on the photostability of acrylate photopolymers used as recording materials

“…However, in order to develop photosensitive materials with advanced performance (higher ∆n), the research was oriented towards phototopolymers doped with dispersed nanoparticles during the last decades. Scientists displayed lots of imagination in investigating this approach; thus TiO 2 [3][4][5][6], SiO 2 [6][7][8][9][10], ZrO 2 [6,[11][12][13], ZrO 2 :Eu 3+ [14], LaPO 4 :Ce 3+ , Tb 3+ [15], LaPO 4 :Tb 3+ nanorods [16], silver [17,18] and gold nanoparticles [19], CdSe [20], CdSe/ZnS [21,22] and ZnO quantum dots (QDs) [23] were used more or less successfully. During the course of the recording process, nanoparticles were forced to diffuse away from the constructive to the destructive interference regions of the interference pattern [7,11,[15][16][17][18][19]21,24].…”