Bipolaron

About: Bipolaron is a research topic. Over the lifetime, 1335 publications have been published within this topic receiving 29154 citations. The topic is also known as: bipolarons.

Nonlinear Optical Phenomena in Cyclotron Resonance of Positive Holes and Electrons in Cu 2 O

Abstract: Nonlinear optical phenomena have been observed for the first time in a new cyclotron resonance experiment on the photoexcited positive holes and/or electrons in Cu 2 O at f =35 GHz, T =4.2 K and at high density excitation P ex ≥100 kW/cm 2 of λ ex =460-750 nm. Unexpectedly, we have observed a nonlinear optical growth of the cyclotron resonance absorption of both holes and electrons at the mid-gap high-density excitation of λ ex ≥690 nm. New experimental results reveal so far unknown specific characters of the conduction and valence electrons in detail and of deep levels as well. Here, we tentatively ascribe these phenomena to a possible condensation of polarons and excitons into a new state in Cu 2 O such as into a bipolaron state via a specific type of double acceptor states.

Time‐resolved spectroscopic studies on phenyl‐substituted poly(phenylenevinylene)s by picosecond excite‐ and probe technique

Abstract: Etude du poly (phenylene-1,4 vinylene [diphenyl-1,2]) et de composes oligomeres et polymeres voisins. Entre 400 et 900 nm. Observation de 3 bandes d'absorption, attribuees respectivement a une espece chargee photogeneree, a un bipolaron et a un etat neutre excite

Evolution of the electronic structure of cyclic polythiophene upon bipolaron doping

Abstract: The evolution of the electronic structure of cyclic polythiophene (PT) upon bipolaron doping is studied to explore the possibility of uniform charge density ground state in the metallic regime. The ground state geometry of the neutral PT, the structure of a single bipolaron, and the experimentally observed optical transitions due to it are reproduced. Since the cyclic PT doped with an odd number of bipolarons (the O configuration) creates an aromatic polyene backbone containing (4n+2)π electrons, it is driven toward the quinoid form. Consequently, we find an insulator‐metal transition for dopant concentration ≥14 mol % and an ∼0.8 eV redshift in Fermi energy with respect to the neutral system at 30 mol % which agree very well with experimental findings. For an even number of bipolarons, there are two possible configurations, namely (i) the (1,1) or the T configuration and (ii) the (2,0)/(0,2) or the S configuration. The T configuration and the O configuration behave similarly and merge to a single asympto...