Premium
Enhanced Energy Transfer in Doped Bifluorene Single Crystals: Prospects for Organic Lasers
Author(s) -
Baronas Paulius,
Kreiza Gediminas,
Mamada Masashi,
Maedera Satoshi,
Adomėnas Povilas,
Adomėnienė Ona,
Kazlauskas Karolis,
Adachi Chihaya,
Juršėnas Saulius
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201901670
Subject(s) - materials science , dopant , lasing threshold , doping , exciton , crystal (programming language) , optoelectronics , laser , amplified spontaneous emission , picosecond , optics , condensed matter physics , wavelength , physics , computer science , programming language
Organic single crystals with long‐range molecular order ensure enhanced carrier mobility and stability as well as emission outcoupling, which makes them attractive as gain medium for electrically pumped organic lasers. Unfortunately, effects of excitonic coupling introduce losses degrading optical performance in crystals, hence higher lasing thresholds are observed compared to amorphous films. Here, crystal doping strategy is investigated as a method to avoid pronounced reabsorption and annihilation losses associated with J‐type excitonic coupling, while taking advantage of enhanced exciton transport for efficient energy transfer. Bifluorene‐based derivatives linked with acetylene and ethylene rigid bridges are suitable as host and dopant system forming high‐quality crystals doped at various concentrations (0.5–11.0%). Enhanced exciton transport in host crystal mediates picosecond host–dopant energy transfer enabling 100% transfer efficiency at lower doping concentrations compared to amorphous films. Amplified spontaneous emission threshold of 1.9 µJ cm −2 in 3.5% doped crystal is enabled by minimized exciton annihilation and emission reabsorption losses at optimal doping concentration.