The role of oxygen-induced processes on the emission characteristics of single molecule emitters

Single molecule studies are limited to a defined class of organic dye molecules inserted into respective host materials. Basic requirements for suited material combinations include high photon emission rates and long term photostability. A majority of known aromatic hostguest systems employ crystalline organic matrices to prevent dye molecules from uncontrolled reactions with contaminants. However, in terms of device fabrication and technological potentials it is often desirable to use polymers as room temperature host matrices. Unfortunately, single dye molecule investigations in polymers at room temperature usually report orders of magnitude lower photostabilities compared to their crystalline molecular counterparts, leading to a reduced interest in organic thin film applications. In this report, we exemplary demonstrate the feasibility of engineering a hostguest system based on dibenzoterrylene dye molecules which were diluted into the polymer poly-(p-phenylene-vinylene) (PPV) possessing very low photobleaching probabilities at room temperature. By controlling the oxygen exposure during manufacturing the number of emitted photons prior to photobleaching was significantly increased from 106 up to 1011 photons. Employing suited encapsulation techniques to prevent oxygen penetration after hostguest preparation, photostable devices over prolonged time periods on the order of months to years could be achieved. Therefore, this approach grants access to a variety of new polymer based combinations of hostguest systems for studying single molecular quantum emitters inside organic electronic devices and nanostructured polymer films with sufficient count rates and long-term stability at room temperature.