Pushûpull dithiole û fluorene acceptors as electron transport materials for holography

π-Extended nitrofluorene-1,3-dithiole chromophore: enhancing the photoresponse of holographic materials through the balance of intramolecular charge transfer and electron affinity

“…10 A marked increase in the photoconductivity was observed in the ICT region of such push-pull fluorene acceptors, which lies around 600 nm allowing the design of extremely efficient materials for hologram recording {with a He-Ne laser (l~632.9 nm) as the source, the holographic response of S g~1% ~100-300 m 2 J 21 and the maximal diffraction efficiency of plane wave holograms of g max ~15-25% were achieved}. 8,11,12 Tuning the ICT energies in backbone 9-(1,3-dithiol-2-ylidene)polynitrofluorene fragments of polythiophenes has also been suggested as an approach to control the bandgap of the polymer. 13 Recently we demonstrated that increasing the length of the bridge between the donor and the acceptor units in compounds of type 1 lowers the ICT energy (bathochromic shift of l ICT ) and increases the intensity of this band.…”

“…13 Recently we demonstrated that increasing the length of the bridge between the donor and the acceptor units in compounds of type 1 lowers the ICT energy (bathochromic shift of l ICT ) and increases the intensity of this band. 8,11 This effect should be reflected in the electrophotographic response of the materials based on such acceptors, resulting in a red shift of the photoresponse maximum. 14 However, tuning the photoconductive properties of the materials requires precise control of several parameters such as the electron affinity of the acceptor (which, generally, decreases as ICT becomes stronger), the planarity and topology of p-p donor-acceptor overlap, stability of the excited state of CTC, (D z ?… A -? )…”

Recent Advances on Nitrofluorene Derivatives: Versatile Electron Acceptors to Create Dyes Absorbing from the Visible to the Near and Far Infrared Region

“…An improvement of the photoconductivity sensitization is also attended if the electron affinity of the chromophore is enhanced, favouring the formation of a charge transfer complex with the sensitized polymer. With aim at optimizing these different parameters (length of the π-conjugated spacer, electron donating/accepting ability of the two partners), a thiophene was introduced between the electron-donating 1,3-dithiole group and the fluorene acceptor (see Figure 10) [64].…”

Synthesis and Reactivity of 3H-1,2-dithiole-3-thiones

“…The second reason for the interest in 1,2-dithioles is the rich chemistry of these compounds which until recently was associated mainly with 1,2-dithiole-3-thiones. For example, many 1,2-dithiole-3-thiones have been employed as precursors for the synthesis of tetrathiafulvalene vinylogues that enhance the nonlinear optical properties for the creation of organic electronic conductors [18], photoconductive materials [19,20], or semiconducting polymers [21].…”