Uniaxial strain tuning of organic molecule single photon sources.

Organic fluorophores are excellent single photon sources, combining high brightness, lifetime-limited linewidths and useful emission wavelengths. A key factor in their performance as photon emitters is their dynamic frequency tunability, which can be used to render the emission from multiple molecules indistinguishable. In this work we demonstrate dynamic tuning of dibenzoterrylene molecules embedded in anthracene crystals through the application of uniaxial strain fields. By bending a piezoelectric strip in two opposite directions in linear steps, we impose an escalating compressive or tensile strain on the molecular crystals, resulting in two opposite dynamic detunings of the dopant dibenzoterrylene emission wavelength. To validate that the tuning mechanism is strain, we performed a similar measurement using an identical strip that was depolarised by annealing in which the tuning was absent. Finally, we simulated the effect of strain on the dopant dibenzoterrylene emission wavelength by combining molecular dynamics and density functional theory techniques to determine the strain tuning rate which matched well with that found experimentally.