High-performance photorefractive polymers sensitized by cadmium selenide nanoparticles

Abstract

We report on efficient and fast hybrid photorefractive polymer sensitized with cadmium selenide ͑CdSe͒ quantum dots. The surface of the quantum dots was treated with 4-methylbenzenethiol. This surfactant is responsible for efficient photoinduced charge generation in the composite, leading to fast grating build-up times of 100 ms and below. Overmodulation of the diffraction efficiency was observed at an applied field of 60 V / m.

High-speed photorefractive composite sensitized by poly(3-hexylthiophene)

“…The maximum diffraction efficiency in sample P3HT, around 35%, was limited by absorption and scattering. 6 The inset of Figure 3 shows the transmittance of the composites, which were measured at five different electric fields between 10 and 50 V/μm. The gain coefficient was measured from two beam coupling experiment.…”

“…PSXCz provided the hole conducting matrix, DB-IP-DC was used as chromophore to confer orientational birefringence and good phase stability to the composite. 6 For reference, PSX-Cz/DB-IP-DC/2,4,7-trinitro-9-fluorenone (TNF) (69/30/ 1 wt%) was also prepared and is referred to as TNF. PSX-Cz and DB-IP-DC were synthesized using previously described methods.…”

“…6,7 The primary step in the formation of a PR grating, the photo-charge generation, is generally achieved in a charge transfer (CT) complex formed between a semiconducting polymer matrix and a sensitizer with a small amount of organic molecules, providing sensitivity in the visible and near infrared. [8][9][10] To date, polymeric PR composites have been sensitized with several classes of organic molecules, such as TNF, 11 TNFM, 12 TCNQ, 13 C 60 , 14 and [6, 6] PCBM; 15 but no PR composites have been sensitized with P3HT.…”

Organic Photorefractive Materials and Applications

“…[ 134 , 140 ] The chemical nature of the capping ligand was found to dramatically infl uence the performance of the QD sensitized PR device. However, a relatively thin shell of the small molecule 4-methylbenzenethiol was ascribed to present only a thin barrier to charge transfer between host and QD, which resulted in astonishing fast PR-response [ 133 ] (see Table 3 ). Contrarily, the direct comparison of 1-hexadecylamine (HDA) capped CdSe QD [ 134 ] yielded two orders of magnitude higher sensitivity compared to tris-n -octylphosphine oxide (TOPO)-capped CdSe particles, [ 141 ] the former molecule forming the thicker capping.…”

Photorefractive effect in a CdS nanoparticles-sensitized polymer composite

“…Nanocomposites containing inorganic quantum dots dispersed in the polymer matrix exhibit increased photogeneration efficiency, broad spectrally tunable photoresponse, and enhanced carrier mobility. Therefore, hybrid organic-inorganic materials with semiconductor nanoparticles have been pursued by several groups [5][6][7] in the development of PR materials in recent years.…”