Optoelectronically active luminescent valine‐substituted perylene diimide: structure‐property correlation via spectroscopic and density functional approaches

Abstract

In literature, the applicability of solution‐phase perylene diimides (PDIs) semiconductors are limited due to their restricted solubility in solvents. In contrast, we synthesized a highly soluble and novel valine‐functionalized PDI derivative (perylene diimide diacid, PDIDA) whose optical and electrical properties were carefully assessed by experimental and density functional approaches. Notably, on valine substitution, the ultraviolet‐visible absorption band centered at 524 nm was attributed to the predominant HOMO ➔ LUMO electronic transition (weighing coefficient = 99 %). Interestingly, the nonuniform variation (W‐shaped) in absorption energy for HOMO ➔ LUMO electronic transition in PDIDA with solvent dielectric constant was experimentally witnessed. The latter was computationally attributed to the more S1 stabilization over So solvent stabilization, particularly in ethanol and dimethyl sulfoxide (DMSO). Furthermore, upon 525 nm excitation, the maximum fluorescence emission was observed at 533 nm with photoluminescence quantum yield as high as 0.77. Interestingly, similar to absorption studies, pronounced influence of solvent polarity was evident on the emission maximum particularly in ethanol and DMSO. Subsequently, electrochemical investigation proved that the PDIDA sustained the intrinsic n‐type semiconductivity with a dielectric constant (εr) 5, a current of 0.54 mA at 5 V, and an electrical conductivity of 1.88 × 10−5 Sm−1. Owing to the above remarkable properties of the synthesized PDIDA, it holds potential applications in photovoltaics, fluorescence‐based detectors and n‐type channel field effect transistors, and so forth.

Semiconductive and Biocompatible Nanofibrils from the Self-Assembly of Amyloid π-Conjugated Peptides

“…This is associated with the known poor solubility of long peptide chains in organic solvents, such as the 32-residue long PDI-[I 10 ] 2 peptide, for which solubility generally requires water. Absorption and emission spectra profiles of PDIs are known to be sensitive to the interchromophore distance and orientation of the PDI cores. , It is also worth noting that absorption and emission spectra of PDIs are highly sensitive to the polarity, viscosity, polarizability, and dielectric constant of the solvent. , For this propose, the A 0–0 / A 0–1 ratio of the dual transition bands, where A 0–0 and A 0–1 are the absorption corresponding to the 0 → 0 and 0 → 1 vibronic transitions from ground to first excited singlet states (S 0→1 ), is widely regarded as an indicator of the aggregation of the PDI moiety. The large A 0–0 / A 0–1 ratio (∼1.60) for PDI-[I 10 ] 2 in DMSO (Table S1) suggests the presence of PDIs in their monomeric state. , The monomeric nature of this symmetric PDI-peptide in DMSO was also confirmed by the corresponding strong emission spectra which is a mirror image of the absorption one in accordance with the Franck–Condon principle (Figure S4).…”

“…21,50 It is also worth noting that absorption and emission spectra of PDIs are highly sensitive to the polarity, viscosity, polarizability, and dielectric constant of the solvent. 51,52 For this propose, the A 0−0 /A 0−1 ratio of the dual transition bands, where A 0−0 and A 0−1 are the absorption corresponding to the 0 → 0 and 0 → 1 vibronic transitions from ground to first excited singlet states (S 0→1 ), 50 is widely regarded as an indicator of the aggregation of the PDI moiety. The large A 0−0 /A 0−1 ratio (∼1.60) for PDI-[I 10 ] 2 in DMSO (Table S1) suggests the presence of PDIs in their monomeric state.…”

Efficient tuning of optoelectronic properties of 1,6- and 1,7-disubstituted perylene diimides: agreement between theory and experiment

“…A solution of the potassium salt of l -valine (1.364 g, 25.09 mmol) was added to the mixture while maintaining the temperature for 5 h under constant stirring. 3 The reaction mixture was then cooled to room temperature and the solvent was evaporated in a rotatory evaporator. Subsequently, ice-cold water was added to it which resulted in the formation of dark maroon precipitates that were filtered and dried under a vacuum.…”

“…1,2 The outstanding optoelectronic properties of PDIs are attributed to their strong absorption at the Q-band (500-700 nm) and B-band (400-450 nm) of the UV visible region, near-unity photoluminescence quantum yields (PLQY), and good photochemical and thermal stability. [3][4][5] Furthermore, their n-type semi-conducting properties make them suitable candidates for their extensive utilization in numerous electronic and optical devices such as organic light-emitting diodes (OLEDs), organic solar cells (OSCs), photosensitizes, sensors, organic field effect transistors (OFETs), light harvesting arrays, dye lasers, and supercapacitors (SCs). [6][7][8][9][10][11] PDIs can structurally be modified by functionalization with electron donor or electron acceptor groups at the peri position (imide position) and/or in the bay region (1,6,7,12-positions) (Fig.…”

“…16 Perylene dianhydride ( PDA ) was brominated using the method reported elsewhere. In the subsequent step, the imidization of brominated PDA was carried out with l -valine (an amino acid) in order to improve the solubility of synthesized PDI s. 3 Further, we report the separation of dibrominated PDI s from multi-brominated products using Soxhlet extraction for the first time. The phenoxy derivatives of PDI s are of particular interest among all the substituents as they could easily be connected to the PDI core by facile nucleophilic substitution.…”