Single-molecule photophysics, from cryogenic to ambient conditions

Abstract

We review recent progress in characterizing and understanding the photophysics of single molecules in condensed matter, mostly at cryogenic temperatures. We discuss the central role of the triplet state in limiting the number of useful host-guest systems, notably a new channel, intermolecular intersystem crossing. Another important limitation to the use of single molecules is their photo-reactivity, leading to blinking of the fluorescence signal, and eventually to its loss by photo-bleaching. These processes are at the heart of modern super-resolution schemes. We then examine some of the new host-guest systems recently discovered following these general principles, and the mechanisms of spectral diffusion and dephasing that they have revealed. When charges are injected into organic conductors, they get trapped and influence single molecules via the local fields they create in the material, and via their coupling to localized vibrations. Understanding these processes is necessary for better control of spectral diffusion and dephasing of single molecules. We finally conclude by giving some outlook on future directions of this fascinating field.

Photophysics of organic semiconductors: from ensemble to the single-molecule level

“…[9][10][11] Single molecules (SM) have also been used as probes of conduction and of exciton dynamics in organic semiconductors. [12][13][14][15] However, because of stringent requirements for the good fluorophores for the SMFS (which include high fluorescence quantum yield and high photostability), studies of local nanoenvironment and its effect on photophysics of organic semiconductors have been limited to a handful of materials. In this paper, we discuss high-performance functionalized organic semiconductor materials which are suitable for systematic studies of photophysics which includes charge and energy transfer, both on the macroscopic (device) level and at nanoscales, down to the SM level.…”

Terrylene in a 2,3-Dichloronaphthalene Crystal. New System for Optical Single-Molecule Investigations

“…The class of molecules, and of guesthost systems, which present appropriate photophysical parameters for such studies is not very extensive. For recent reviews of the singlemolecule studies see references [1] and [2].…”

Sensing Inside the Living Cells

“…For example, several single-molecule systems have unexpectedly shown some form of stochastic behavior, such as " blinking " -reversible transitions between emissive and non-emissive states (Kozankiewicz and Orrit 2014 ;Ha and Tinnefeld 2012 ). Such fl uctuations are important diagnostics of the single-molecule regime, needed in resolving the excited states of different fl uorescent nanoparticles.…”