Mesoscopic quantum emitters from deterministic aggregates of conjugated polymers

• DOI: 10.1073/pnas.1512582112
• Publication Date: 2015-09-29T02:53:45Z
• Authors: Thomas Stangl; Philipp Wilhelm; Klaas Remmerssen; Sigurd Höger; Jan Vogelsang; John M. Lupton
• Keywords: Mesoscopic physics; J-aggregate

An appealing definition of the term "molecule" arises from consideration nature fluorescence, with discrete molecular entities emitting a stream single photons. We address question how large object may become by growing deterministic aggregates conjugated polymer chains. Even particles containing dozens individual chains still behave as quantum emitters due to efficient excitation energy transfer, whereas brightness is raised increased absorption cross-section suprastructure. Excitation can delocalize between chromophores in these both coherent and incoherent coupling, which are differentiated their distinct spectroscopic fingerprints. Coherent coupling identified 10-fold increase excited-state lifetime corresponding spectral red shift. Exciton quenching FRET becomes more significant aggregate size increases, resulting single-aggregate emission characterized strong blinking. This mesoscale approach allows us identify intermolecular interactions do not exist isolated inaccessible bulk films where they present but masked disorder.