Assembly Induced Super-Large Red-Shifted Absorption: The Burgeoning Field of Organic Near-Infrared Materials

Abstract

Supramolecular assembly of organic dye compounds with J-aggregation leads to a red-shifted absorption spectrum that greatly facilitates the construction of near-infrared (NIR) materials. A considerable improvement of the material functions requires that the absorption red-shift be larger than 100 nm, but such a super-large red-shift is challenging, and the rules leading to the super-large red-shifted absorption is still not explicit. In this review, we focused on those J-aggregated organic dye materials with super-large red-shifted absorption. The nature of the super-large red-shift is originated from the intermolecular charge transfer between neighboring chromophores. The super-large red-shift can be obtained by tuning either the molecular structure or kinetic assembly process in a delicate manner. Materials with super-large red-shifted absorption have been successfully applied to biological imaging, phototherapy, electronic devices, and solar cells, and show great potential in many other fields. The elaboration of assembly induced super-large red-shifted absorption is promising for design of supramolecular NIR materials with tuned structures, enhanced functionalities, and a wide array of applications.

Amino‐Acid‐Encoded Supramolecular Photothermal Nanomedicine for Enhanced Cancer Therapy

“…[ 13 ] For spherical morphology of PFF‐NPs, it is the balance between hydrophobic interaction and electrostatic force that plays a key role in forming the well‐dispersed colloidal nanoparticles. [ 6c ] Dynamic light scattering (DLS) results revealed that the PFF‐NPs had a diameter of 80 ± 25 nm (Figure 1b), consistent with the microscopic observation. The zeta potential values of the PD‐NFs, PDD‐NFs, PDDDD‐NFs, PFF‐NPs, and PYY‐NFs were determined to equal −25.3 ± 6.0 mV, −25.0 ± 6.1 mV, −28.5 ± 6.7 mV, −30.9 ± 8.0 mV, and −28.8 ± 6.7 mV, respectively (Figure 1c).…”

“…[ 5 ] Therefore, supramolecular photothermal nanodrugs constructed through the self‐assembly of biomolecules have been proposed as promising candidates for cancer PTT. [ 6 ]…”

“…As representative self‐assembling biomolecules, peptides have been recently utilized as attractive building blocks for the supramolecular construction of photothermal nanodrugs with a combination of photosensitizers. [ 6c,7 ] The photothermal conversion efficiencies of such nanodrugs are mainly determined by the molecular organized patterns of photosensitizers, which are highly controlled by the noncovalent interactions among peptides and photosensitizers. Consequently, disassembly of the nanodrugs diminishes the photothermal effect, recovers the intrinsic photodynamic effect of photosensitizers, and thereby enables photodynamic therapy (PDT).…”

Segregated Array Tailoring Charge‐Transfer Degree of Organic Cocrystal for the Efficient Near‐Infrared Emission beyond 760 nm

“…It is well known that the packing mode of F 4 TCNQ‐based CT complexes plays a crucial effect to dominate their optoelectronic properties. [ 8 ] Electron spin resonance (ESR) measurements were performed to study the relationship between the packing mode, radical concentration, and optoelectronic features in the CT complex. As shown in Figure 1c, these prepared F 4 TCNQ‐based CT complexes present the obvious ESR signal, which is consistent with the character of the CT interaction in ground state.…”

Porous Pyrene Organic Cage with Unusual Absorption Bathochromic-Shift Enables Visible Light Photocatalysis

“…[4][5][6][7][8][9][10][11][12][13] The functionalities of molecular superstructures are strongly dependent on the intermolecular packing because of the strong coupling between the electronic and structural dynamics of the molecular units in the solid state. In particular, the electron transport, 5 fluorescence, 6 and electronic absorption 14,15 of solid assemblies from conjugated molecules are strongly associated with aggregated structures. For example, the parallel aligned aromatic chromophores in various supramolecular assemblies with tilt angle (θ) <54.78°(J-aggregate definition) allow electronic excitation from the ground state to the excited state with lower energy relative to the monomeric molecules, resulting in an absorbance bathochromic-shift (Scheme 1a).…”