Abstract
Magnetic field effect (MFE) on pyrene-N,N-dimethylaniline (Py-DMA) exciplex system in benzene-acetonitrile (Bz-ACN) mixtures of varying bulk permittivity (e) has been studied. The MFE has been wavelength resolved over the emission band of the exciplex along with the measurement of lifetime. The data establishes the concept of formation of two types of exciplexes (Relaxed and Un-relaxed) at higher bulk value of permittivity. At lower value of permittivity when solvent reorganization energy is not so prominent effectively only a single type of exciplex (Relaxed) is formed. The data also indicates that the benzene π cloud favors formation of relaxed exciplex.
Highlights
Magnetic field effect (MFE) on exciplex luminescence is a wellstudied phenomenon [1,2,3,4]
In absence of external magnetic field hyperfine interaction mixes the singlet and triplet states of the radical ion pairs (RIP) generated by photo-induced electron transfer (ET) and triplet leakage occurs from the singlet precursor RIP
In the present work we have extended this study in case of another aprotic binary solvent mixtures, benzeneacetonitrile, for Py-DMA exciplex system
Summary
Magnetic field effect (MFE) on exciplex luminescence is a wellstudied phenomenon [1,2,3,4]. For lower value of dielectric constant (ε ≤ 9) the life-time signature is essentially same over the whole exciplex band (homogeneous broadening, single species). This comprises a growth which matches with the pyrene decay at 384 nm and a decay which becomes faster with increase in value of ε. At the middle and the red end of the exciplex band the signature remains the same i.e., we observe a growth and a decay This observation has been explained on the basis of multiple exciplexes formation at higher dielectric constant (DC, ε). At lower value of dielectric constant where the solvent reorganization energy is low, this differentiation doesn’t occur and we have essentially a single type of exciplex, only the relaxed one. The data effectively supports the model of formation of relaxed (R) and un-relaxed (U) exciplexes depending on the bulk value of dielectric constant
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
