Related papers: Essential optical states in $\pi$-conjugated polym…
The formation of excited dimer states, so called excimers, is an important phenomenon in many organic molecular semiconductors. In contrast to Frenkel exciton-polaron excited states, an excimer is long-lived and energetically low-lying due…
The number of excitons that conjugated polymers can support at any one time underpins their optoelectronic performance in light emitting diodes and as laser gain media, as it sets a natural limit on exciton density. Here we have measured…
Component of photoexcited states with large spatial extent is investigated for optical absorption spectra of the electroluminescent conjugated polymers by using the intermediate exciton theory. We calculate the ratio of oscillator strengths…
Although coherent light is usually required for the self-organization of regular spatial patterns from optical beams, we show that peculiar light matter interaction can break this evidence. In the traditional method to record laser-induced…
The component of photoexcited states with large spatial extent is investigated for poly(para-phenylenevinylene) using the intermediate exciton theory. We find a peak due to long-range excitons at the higher-energy side of the lowest main…
Organic semiconducting polymers are currently of broad interest as potential low-cost materials for photovoltaic and light-emitting display applications. I will give an overview of our work in developing a consistent quantum dynamical…
We have studied the exciton states in two coupled conjugated polymer chains which are modeled individually by the Su-Schrieffer-Heeger Hamiltonian and coupled by an interchain electron-transfer term. Both the intra- and inter-chain long…
Conjugated polymers offer potential for many diverse applications but we still lack a fundamental microscopic understanding of their electronic structure. Elementary photoexcitations - excitons - span only a few nanometres of a molecule,…
We investigate the effect of exciton coupling on the optical absorption spectrum of polymer molecules under conditions of strong inhomogeneous broadening. We demonstrate that the dependence of the maximum in the rescaled absorption spectrum…
Photoexcitation of planar Wannier excitons by twisted photons in thin semiconductor films is investigated. The explicit general formulas for transition probabilities between exciton states are derived. The selection rules for the projection…
Photoluminescence is commonly used to identify the electronic structure of individual nanotubes. But, nanotubes naturally occur in bundles. Thus, we investigate photoluminescence of nanotube bundles. We show that their complex spectra are…
Electronic structures and optical excitations in Moebius conjugated polymers are studied theoretically. Periodic and Moebius boundary conditions are applied to the tight binding model of poly(para-phenylene), taking exciton effects into…
The nature of the primary photoexcitations in semiconducting single-walled carbon nanotubes (S-SWCNTs) is of strong current interest. We have studied the emission spectra of S-SWCNTs and two different $\pi$-conjugated polymers in solutions…
The saga of the primary photoexcitations in $\pi$-conjugated polymers has been a source of extraordinary scientific curiosity that has lasted for more than three decades. From soliton excitations in trans-polyacetylene, to singlet and…
We propose a system of highly efficient photoemitters comprising metal-dielectric (plasmonic-excitonic) multilayered structures. In the proposed structure, the absorption in the excitonic layer is greatly enhanced through quantum…
We employ five {\pi}-conjugated model materials of different molecular shape --- oligomers and cyclic structures --- to investigate the extent of exciton self-trapping and torsional motion of the molecular framework following optical…
We perform ab initio calculations of optical properties for a typical semiconductor conjugated polymer, poly-para-phenylenevinylene, in both isolated chain and crystalline packing. In order to obtain results for excitonic energies and…
We address the role of excitonic coulping on the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical…
Natural photosynthetic photonic nanostructures can show sophisticated light matter-interactions including enhanced light absorption by slow light even for highly pigmented systems. Beyond fundamental biology aspects these natural…
There is an enormous potential in applying conjugated polymers in novel organic opto-electronic devices such as light emitting diodes and solar cells. Although prototypes and first products exist, a comprehensive understanding of the…