A new class of photoswitches and the corresponding elementary photoinduced reaction, the so-called Excited-State Cation Transfer (ESCT), are investigated. This reaction relies on an intramolecular photo-release/photo-complexation of cation: after irradiation, the cation is translocated from a complexation site 1 to a site 2 during the excited state lifetime. Our purpose is thus to develop a computational strategy based on Density Functional theory (DFT) and its time-dependent counterpart (TD-DFT) to improve the different properties of the ESCT photoswitches, namely (i) the ground state complexation constant , (ii) the excited state complexation constant *, (iii) the photoejection properties and (iv) the population of the triplet states from a singlet state intersystem crossing to increase the lifetime of the excited state. In this work, we are interested in optimizing the ESCT properties of a betaine pyridinium chromophore substituted by a 15-aza-5-crown, that was previously shown to efficiently photoeject a Ca cation from the site 1 but no photo-recapture was observed in the site 2 [Aloïse , ., 2016, , 15384]. To this purpose, we have investigated the impact of the modification of the site 1 on the ESCT properties by introducing different substituents (EDG groups, halogen atoms) at different positions. So far, promising systems have been identified but a simultaneous improvement of all the ESCT photoswitches properties has yet not been achieved.
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http://dx.doi.org/10.1039/d3cp04988d | DOI Listing |
Sci Rep
January 2025
Department of Physics, K.S.M Devaswom Board College, Sasthamcotta, Kollam, India.
Transition metal based optical limiting materials have garnered significant attention due their crucial role in protecting sensitive optical system from high intense laser damage. Transition metal molybdates exhibits nonlinear optical (NLO) response, which attenuate highly intense light by transmitting light of desired intensity. Herein we report Silver molybdate (AgMoO) nanostructures doped with erbium (Er) ions were successfully synthesized by simple co-precipitation technique.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Indian Institute of Technology, Guwahati 781039, India.
Charge transfer (CT) states in polycyclic aromatic hydrocarbons play crucial roles in determining their electronic properties and their potential applications in organic electronics. In this work, we investigate the nature of the excited states in monomers and π-stacked dimers of azulene-fused naphthalene and anthracene systems, focusing on the interplay between structure and excited-state properties. Four different isomers for azulene-fused naphthalene (, , , and ) and anthracene (, , , and ) are considered.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Lab of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275, China.
Optical responses of twisted bilayer graphene at targeted wavelengths can be amplified by leveraging energy levels of van Hove singularities (VHS) via tuning periods of moiré superlattices. Therefore, precise control of twist angles as well as the moiré superlattices is necessary for fabricating integrated optoelectronic devices such as photodetectors and emitters. Although recent advances in twist angle control help the observation of correlated states in twisted magic-angle graphene structures, the impact of such precise control on enhanced optical absorption is still under investigation.
View Article and Find Full Text PDFChem Asian J
January 2025
Universite de Rennes 1, Sciences Chimiques de Rennes - UMR 6226, Avenue du General Leclerc, Campus de Beaulieu, 35042, Rennes, FRANCE.
A novel coordination motif comprising [4]helicene fused with pyrazino-phenanthroline (H4PP) has been synthesized and reacted with ReCl(CO)5 to yield its rhenium(I) complex (Re-H4PP). Absorption and emission spectroscopic analysis conducted in dichloromethane and 2-methyltetrahydrofuran reveals that combining pyrazino-phenanthroline with helicene visibly affects the photophysical attributes of both the resulting ligand and its Re(I) complex as compared to their non-helicene analogues, and even more importantly leads to relatively high photoluminescence quantum yield values, especially in the case of H4PP (29%). Chiroptical studies through electronic circular dichroism and circularly polarized luminescence performed on enantiomerically enriched samples of Re-H4PP show the chiral nature of low-energy excited states affording notable glum values that amplify at cryogenic temperatures.
View Article and Find Full Text PDFNano Lett
January 2025
Center for Quantum Nanoscience, Institute for Basic Science, Seoul 03760, South Korea.
We demonstrate the reversible control of interactions between a local molecular spin, hosted within an iron phthalocyanine (FePc) molecule, and the conduction electrons of a supporting Au(111) surface. Using the tip of a scanning tunneling microscope, we deliberately and reversibly manipulate the adsorption configuration of the molecule relative to the underlying substrate lattice. Different rotation configurations lead to noticeable changes in the differential conductance measured on the FePc molecules.
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