相关论文: Frenkel Excitons--Charge-Transfer Excitons--Phonon…
In molecular crystals like MePTCDI and PTCDA the molecule are regularly arranged creating quasi-one-dimensional molecular stacks. The intermolecular distance in a stack (about 3.3 A) is comparable with the electron--hole distance in the…
Excitonic and vibronic spectra of Frenkel excitons (FEs) in a two-dimensional (2D) lattice with one molecule per unit cell have been studied and their manifestation in the linear absorption is simulated. We use the Green function formalism,…
Linear and non-linear spectroscopies are powerful tools used to investigate the energetics and dynamics of electronic excited states of both molecules and crystals. While highly accurate \emph{ab initio} calculations of molecular spectra…
We investigated optical absorption spectra near the fundamental absorption edge of beta-FeSi2 single crystals by transmission measurements. The phonon structure corresponding to the emission and absorption component was clearly observed in…
The problem of the one-exciton absorption spectrum is considered for the lattice of two-level interacting atoms whose initial energy splitting depends on the coordinate. It is shown that for some types of interatomic interaction, this…
A method is proposed for calculating the absorption spectrum of a long one-dimensional closed-into-a-ring chain with Frenkel's exciton under diagonal disorder. This disorder is represented by the hyperbolic singularities of atomic fission.…
Spectral density functions are central to the simulation of complex many body systems. Their determination requires to make approximations not only to the dynamics but also to the underlying electronic structure theory. Here, blending…
Bound and unbound Frenkel-exciton pairs are essential transient precursors for a variety of photophysical and biochemical processes. In this work, we identify bound and unbound {Frenkel}-exciton complexes in an electron push-pull polymer…
The concept of \textit{optical} exciton - a photo-excited bound electron-hole pair within a crystal - is routinely used to interpret and model a wealth of excited-state phenomena in semiconductors. Beside originating sub-band gap signatures…
We study the dynamics of a single Frenkel exciton in a disordered molecular chain. The coherent-potential approximation (CPA) is applied to the situation when the single-molecule excitation energies as well as the transition dipole moments,…
We consider the dynamics of Frenkel excitons on quasiperiodic lattices, focusing our attention on the Fibonacci case as a typical example. We evaluate the absorption spectrum by solving numerically the equation of motion of the…
Understanding the nature of molecular excitons in low-dimensional molecular solids is of paramount importance in fundamental photophysics and various applications such as energy harvesting, switching electronics and display devices. Despite…
One-dimensional semiconductors are characterized by strongly bound excitons. Therefore, the Frenkel regime of excitons localized within a few unit cells is readily reached and traditional Wannier exciton models become inadequate. In the…
Electroabsorption (EA) measurements can be used to identify the type of excitons contributing to the absorption spectra of semiconductors which have applications in optoelectronics. However, the inferences from the EA measurement greatly…
We revisit low-temperature optical spectra of transition-metal dichalcogenide monolayers and point to a possible crystallization of electrons (or holes) at low to moderate charge densities. To calculate the excitonic spectra under such…
We present a comprehensive theoretical analysis of composite excitonic states in doped transition-metal dichalcogenide monolayers. Making use of the pair distribution function, we introduce a method to include the effect of screening in the…
Non-radiative exciton relaxation processes are critical for energy transduction efficiencies in optoelectronic materials, but how these processes are connected to the underlying crystal structure and its associated electron, exciton, and…
Low-temperature (1.8 K) excitonic absorption, reflection and photoluminescence spectra of mixed $Zn(P_{1 - x}As_{x})_{2}$ crystals were studied at $x = $0.01, 0.02, 0.03 and 0.05. Energy gap and rydbergs of excitonic B, C and A-series…
In organic semiconductors working under ambient circumstance, there are remarkable quantum effects lack of comprehensive understanding, and an exotic composite particle named charge transfer (CT) exciton is normally regarded as the key…
Monolayers of transition metal dichalcogenides (TMDC) are direct-gap semiconductors with strong light-matter interactions featuring tightly bound excitons, while plasmonic crystals (PCs), consisting of metal nanoparticles that act as…