Energy-Transfer Processes in Donor–Acceptor Poly(fluorenevinylene-alt-4,7-dithienyl-2,1,3-benzothiadiazole)

Abstract

The emission ellipsometry technique was applied to the donor−acceptor structure, poly[9,9′-dioctyl-2,7-fluorenevinylene-alt-4,7-(di-2,5-thienyl)-2,1,3-benzothiadiazole], to quantify the energy transferred from the donor (fluorene) to the acceptor (thiophene−benzothiadiazole−thiophene). The relative contributions to the total emission from both donor and acceptor were determined and also the amount of the emitting species that lost coherence with the polarization of the excitation light. The results were discussed in terms of energy transfer via multiphonon processes.

Achromatic Ellipsometry: Theory and Applications

“…In 1946, the Nobel laureate Subrahmanyan Chandrasekhar formulated the equations for radioactive transfer of partially polarized light [12], which was only possible due to Stokes' work. In addition to Stokes theory, new material developments for achromatic optical elements made possible the measuring of all polarization states as a function of wavelengths (optical spectrum), i.e., the necessary observables to enlighten the materials structure [2,13,14,17,18].…”

“…It allows the characterization of several states of light polarization using one equation [14,18] and can result in forms interpreted as linearly and circularly polarized light. Beyond that, from the concept of polarization ellipse, it is possible to understand Stokes' description to identify all states of light polarization, including partially polarized beams [12].…”

“…It is also likely to obtain the polarization degree (P) for the emerging light, from Eq. (18). In addition, Alliprandini-Filho [2], describes the asymmetry factor (g) and Circular Dichroism acquired from Stokes parameters, providing more complex information about the chirality of the molecules that compose the studied material.…”

Electrochemical Deposition of P3AT Films Used as a Probe of Optical Properties in Polymeric System

“…This result has been discussed in terms of the efective conjugation length, since the dynamics of the excited species are inluenced by the occurrence of a twist between the vicinity of the thiophene rings together with the interchain interaction. In the last decade, the interest in the organic electronic devices has increased signiicantly; however, some efects on their operation are not fully understood, in particular the interface efects of the substrate/polymer and energy transfer of excited carriers [9,[14][15][16]. Since the physical-chemistry properties and investigation of organic active layers, such as P3ATs thin solid ilms, can elucidate the development of new optoelectronic devices [16][17][18].…”

“…In the last decade, the interest in the organic electronic devices has increased signiicantly; however, some efects on their operation are not fully understood, in particular the interface efects of the substrate/polymer and energy transfer of excited carriers [9,[14][15][16]. Since the physical-chemistry properties and investigation of organic active layers, such as P3ATs thin solid ilms, can elucidate the development of new optoelectronic devices [16][17][18]. Interface efects cause signiicant quenching of excited carriers and it is commonly investigated by conventional spectroscopic techniques [15,19], such as ultraviolet-visible absorption (UV-Vis), photoluminescence (PL), photoluminescence excitation (PLE), vibrational spectroscopy (FT-IR and RAMAN) [8,12,20,21] and the morphological technique of atomic force microscopy (AFM) [22][23][24].…”