Statistical Model and Experiments on Low‐Dimensional Exciton Transport

Abstract

A statistical model is presented to calculate the concentration dependence of the ESR line width of triplct excitons in mixed CT crystals. A comparison between computation and experiments yields the anisotropy of energy diffusion. As experimental example data on the cha,rge-transfer crystal anthracenec-phenanthrenel -,-TCNB (0 5 c 5 1) are presented. It is shown that triplet excitons move by a factor of 15 to 60 faster along one distinct direction than perpendicular to it.Es wird ein statistisches Modell zur Berechnung der Konzentrationsabhangigkeit der ESR-Linienbreit.e von Triplett-Exzitonen in CT-Mischkristallen angegehen. Der Vergleich zwischen Rechnung und Experimentcn liefert die Anisotropie der Energiediffusion. Als experimentelles Beispiel werden Werte des Ladungstransferkristalls Anthrazen,-Phenantrenl -,-TCNB (0 5 c 5 1) mitgeteilt,.Es wird gezeigt, da8 sich Triplett-Exzitonen um einen Faktor 15 bis 60 schneller in einer bestimmten Richtung bewegen, als senkrecht dazu.

Mechanism of Ultrafast Triplet Exciton Formation in Single Cocrystals of π-Stacked Electron Donors and Acceptors

“…Interest in organic donor–acceptor (D–A) cocrystals for potential electronic and photonic applications − is growing rapidly due to the ease of designing cocrystals having properties such as ferroelectricity, , ambipolar charge transport, ,− photonic waveguiding, − tunable emission, ,− and near-infrared absorption . Early work on triplet excitons in D–A cocrystals focused largely on their diffusion through quasi-1D π-stacks, degree of charge transfer (CT) character, and decay kinetics. − Recent studies have dealt with CT intermediates in singlet fission, , triplet–triplet annihilation leading to photon upconversion, , and applications in photodynamic therapy. − …”