Room-temperature lasing from fluorene thin-film crystals densely doped with anthracene.
The potential for room-temperature lasing in densely doped organic crystals has been examined using (fluorene)0.8-(anthracene)0.2 thin crystals fabricated in a narrow gap between two quartz plates. An excitation-intensity dependence study confirms that the system shows spectral line narrowing, a super linear increase of the narrow line above threshold excitation intensity, and laser cavity modes. These results indicate that lasing has been observed in the densely doped organic crystal, which contains in-plane cavities with a length of approximately 100 μm.
Stimulated emission from anthracene aggregates in fluorene crystals fabricated by cell method
In fluorene(80%)–anthracene(20%) mixed crystals, mainly observed luminescence is broad D2 bands, which originates from an excitation state localized on two anthracene molecules and is accompanied by lattice relaxation. Under high intensity excitation, several sharp luminescence lines emerged in the high energy side of the D2 0–1 bands and their intensity increased superlinearly with excitation intensity. The decay time of the luminescence lines is 30 ps, which is two orders of magnitude smaller than decay time under low intensity excitation. These results suggest that sharp luminescence lines are stimulated luminescence from D2 centers. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescence of anthracene molecules in single crystal matrices
Optical properties of single fluorene/phenanthrene crystals doped with various mole fraction of anthracene, 10–5 to a few %, were investigated at 10 K. In low concentration samples, sharp structures attributed to isolated anthracene molecules were observed. Inhomogeneous width in their 0-0 energy were found to be ∼20 cm–1. When concentration is higher, spectral species, which are distinctly different from the isolated molecule spectrum, were observed and their origins are discussed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)