Exploring Through-Space Charge Transfer-Mediated Optoelectrochemical Properties of Dual-State Luminescent Aliphatic Polymers and Optoelectronic Responses toward Metal Ions

• Published in: Langmuir 2024-10, Vol.40 (42), p.22265-22282
• Main Authors: Chowdhury, Deepak, Hassan, Nadira, Roy, Shrestha, Sanfui, MD Hussain, Nandy, Preetam, Chang, Mincheol, Rahaman, Mostafizur, Ghosh, Narendra Nath, Hasnat, Mohammad A., Chattopadhyay, Pijush Kanti, Maiti, Dilip K., Singha, Nayan Ranjan
• Format: Article
• Language: English
• ISSN: 0743-7463; 1520-5827; 1520-5827
• DOI: 10.1021/acs.langmuir.4c02890

Herein, natural-synthetic hybrid dual-state luminescent conducting polymers (DLCPs/DLCP1–DLCP8) possessing significant optoelectrochemical properties are strategically developed by the polymerization of prop-2-enamide, cis-butenedioic acid, 2-acrylamido-2-methylpropane-1-sulfonic acid, and in situ-generated 2-(3-acrylamidopropanamido)-2-methylpropane-1-sulfonic acid alongside the grafting of gum tragacanth. The spectroscopic data of aliphatic DLCPs affirm DLCP7 as the most stable supramolecular assembly endowing optoelectronic properties. Computational calculations identified −C­(O)­NH–, −C­(O)­OH, −OH, and −SO3H as subluminophores. The absorption spectra, excitation wavelength-/solvent-polarity-/concentration-dependent luminescence, solid state luminescence, aggregation-induced enhanced luminescence, and time-correlated single photon count (TCSPC) studies confirm the occurrence of aggregation-mediated intramolecular through-space charge transfer (ITSCT) in the excited state of DLCP7. Mulliken charge, natural bond orbital, dipole moments, and electronic potential surface analyses confirm the charge donor–acceptor system in DLCP7. Furthermore, the selective optoelectronic response of DLCP7 toward Ca2+/Cu­(II) at 438/574 nm is explored using ultraviolet–visible spectra, TCSPC analyses, a dynamic light scattering study, and computational investigations. The chelation-enhanced luminescence and ITSCT inhibition are responsible for turn-on and turn-off detections of Ca2+ and Cu­(II), respectively. Cu­(II) → Cu­(I) reduction in a DLCP7 solution is inferred from electrochemical and spectroscopic analyses. The conductivities of 9.65 × 10–5 S cm–1 (solid state) and 44.35 × 10–5 S cm–1 (solution) in DLCP7 are validated by current–voltage and electrochemical impedance measurements. Again, strong electronic conductivities of 43.89 × 10–5 S cm–1 (solid state)/53.34 × 10–5 S cm–1 (solution) and 45.42 × 10–5 S cm–1 (solid state)/64.81 × 10–5 S cm–1 (solution) are observed in Ca2+-DLCP7 and Cu­(II)-DLCP7, respectively.