Single dibenzoterrylene molecules in an anthracene crystal: Spectroscopy and photophysics

We study, single dibenzoterrylene molecules in an anthrocene single crystal at 1.4 K in two insertion sites at 785.1 and 794.3 nm. The single-molecule zero-phonon lines are, narrow (about 30 MHz), intense (the detected fluorescence rates at saturation reach 100,000 counts s(-1)), and very photostable. The intersystem-crossing yield is extremely low (10(-7) or lower). All of these features are hallmarks of an excellent system for high-resolution spectroscopy and nonoscale probing at cryogenic temperatures.