Electric-field effects on photoinduced dynamics and function

Abstract

Photoinduced electron-transfer processes are enhanced or quenched by application of electric fields, depending on the donor-acceptor pairs. Electric-field-induced quenching of photoluminescence, which results from the field-induced dissociation of the exciton state that depends on the photoexcitation wavelength, is observed in π-conjugated polymers. These electric-field effects on photoinduced dynamics have been confirmed by the measurements both of electroabsorption and electrophotoluminescence spectra and of time-resolved electrophotoluminescence decays. Time-resolved measurements of photocurrent, with which novel material function in electrical conductivity of organic materials induced by photo irradiation and application of electric fields is confirmed, are also reviewed.

Influence of External Electric Fields on Photoluminescence and Charge Carrier Dynamics of π-Conjugated Polymer P3HT in Multilayer Films with Heterojunctions to TiO2 and Sb2S3

“…According to the theory of electric field effects on optical spectra, ,,,− field-induced change in absorbance for molecules can be expressed as a linear combination of the zeroth, first, and second derivatives of the absorption spectra: where ν is the wavenumber of light, A (ν) is the absorbance at ν, f is the internal field factor, F is the field strength, and A χ , B χ , and C χ are the coefficients for the zeroth, first, and second derivatives of A (ν), respectively. We carried out the experiments at a magic angle condition of χ = 54.7°, where χ is the angle between the external electric field, F , and polarization direction of the excitation light.…”

“…In general, Stark spectroscopy including E-PL measurements detects the signal at the second harmonic of the modulation frequency of applied electric fields. We can deduce the second-order Stark effect from this type of conventional experiments. , Further, we employed the first harmonic detection of the modulated electric field with the aim to obtain insight into anisotropic dynamics existing in the cell, in addition to the quadratic field effect. By changing the polarity of the electrodes of FTO and Ag, we changed the direction of the applied electric field on the cell and extracted anisotropic response which depends on the direction of applied electric fields.…”

Fluorescence enhancement induced by quadratic electric-field effects on singlet exciton dynamics in poly(3-hexylthiophene) dispersed in poly(methyl methacrylate)

“…The field-induced change in absorbance for molecules can be expressed as a linear combination of the zeroth, first, and second derivatives of the absorption spectra: [54][55][56][57][58] Δ𝐴(𝜈) = (𝑓𝐹) 4 5𝐴 6 𝐴(𝜈) + 𝐵 6 ν :(;(<)/<) :< + 𝐶 6 ν : ? (;(<)/<) : ?…”

Optical-field driven charge-transfer modulations near composite nanostructures

“…However, IDI alone monotonously decreases with distance and then fails at explaining both the modulations and the phase shift of the charge-transfer dynamics herein reported. By analogy between external electric 60,61 and optical fields, we argue that the external electromagnetic waves induce a perturbation of the driving force and reorganization energy due to the quasi-static dipole moment of charge-transfer states. The mathematical formalism is detailed in the Supplementary Information, but the key parameters are i) the difference between the dipole moment vectors in the initial and final charge transfer states (Δμ), and ii) the optical field inside the medium (F).…”