Counter Anion Effect on the Photophysical Properties of Emissive Indolizine-Cyanine Dyes in Solution and Solid State

Abstract

Near-infrared emissive materials with tunable Stokes shifts and solid-state emissions are needed for several active research areas and applications. To aid in addressing this need, a series of indolizine-cyanine compounds varying only the anions based on size, dipole, and hydrophilicity were prepared. The effect of the non-covalently bound anions on the absorption and emission properties of identical π-system indolizine-cyanine compounds were measured in solution and as thin films. Interestingly, the anion choice has a significant influence on the Stokes shift and molar absorptivities of the dyes in solution. In the solid-state, the anion choice was found to have an effect on the formation of aggregate states with higher energy absorptions than the parent monomer compound. The dyes were found to be emissive in the NIR region, with emissions peaking at near 900 nm for specific solvent and anion selections.

Impact of the anion on electrochemically doped regioregular and regiorandom poly(3‐hexylthiophene)

“…] 2 ) 4 À . 41,42 The family of tetraphenyl borates contain varying extents of fluorination, with the original intent of varying the electronegativity of the periphery. Tetraphenylborate was also investigated; however, the spectroelectrochemistry data presented in Figures S1 and S2 show that tetraphenylborate is unable to support significant polaron formation on rr-P3HT or rra-P3HT.…”

Nature‐Inspired Functional Chromophores from Biomimetic o‐Quinone Chemistry

“…To be defined "functional", a chromophore must display specific properties associated with, e. g., acidichromism, solvatochromism or intense light emission (fluorophores) upon excitation with solar or visible light. [5,6] In most cases, tunable chromophoric properties can be achieved via rational combination of donor-acceptor (D-A) conjugate motifs, as typically exemplified by the aux-ochrome and antiauxochrome disposition at the termini of an even numbered polymethine chain in merocyanine dyes. [7][8][9] Interestingly, in an ever-increasing number of cases an important role in the overall optical and electronic performance of functional dyes is attributed to aggregation, which may be governed by hydrogen bonding or stacking interactions.…”

“…The commonly accepted definition of chromophore denotes a π‐system with a suitable degree of delocalization to allow for a HOMO‐LUMO gap compatible with efficient electronic transitions, usually in the visible region (dyes). To be defined “functional”, a chromophore must display specific properties associated with, e. g ., acidichromism, solvatochromism or intense light emission (fluorophores) upon excitation with solar or visible light [5,6] . In most cases, tunable chromophoric properties can be achieved via rational combination of donor‐acceptor (D‐A) conjugate motifs, as typically exemplified by the auxochrome and antiauxochrome disposition at the termini of an even numbered polymethine chain in merocyanine dyes [7–9] …”

Group of Uniform Materials Based on Organic Salts (GUMBOS): A Review of Their Solid State Properties and Applications

“…When implemented in this field, tunable investigations of co-sensitizing dyes that are also ionic and primarily limited to structural variations of zwitterionic squaraine-heptamethine structures rather than ion pairs [216,217]. Polymethine, or cyanine dyes, however, have been extensively studied in OPV technologies, and several groups have begun explorations into counterion application in DSSCs [218][219][220][221][222][223].…”