Reverse Intersystem Crossing of Single Deuterated Perylene Molecules in a Dibenzothiophene Matrix

Abstract

Intersystem crossing to the long-lived metastable triplet state is often a strong limitation on fluorescence brightness of single molecules, particularly for perylene in various matrices. In this paper, we report on a strong excitation-induced reverse intersystem crossing (rISC), a process where single perylene molecules in a dibenzothiophene matrix recover faster from the triplet state, turning into bright emitters at saturated excitation powers. With a detailed study of single-molecule fluorescence autocorrelations, we quantify the effect of rISC. The intrinsic lifetimes found for the two effective triplet states (8.5 � 0.4 ms and 64 � 12 ms) become significantly shorter, into the submillisecond range, as the excitation power increases and fluorescence brightness is ultimately enhanced at least fourfold. Our results are relevant for the understanding of triplet state manipulation of single-molecule quantum emitters and for markedly improving their brightness.

Intermolecular singlet fission in a radical dianion system in solution phase

“…Certainly, the generated two free triplets will eventually return to their singlet ground-state through intersystem crossing and the lifetime of such a T 1 → S 0 transition for perylene derivatives can be quite long (i.e., a few or few tens of milliseconds). 24,25 Taken together, the above ns-TA spectroscopic results furnish the post-1 (T 1 T 1 ) events as follows: 1 (T 1 T 1 )…”

Probing the in‐plane dipole moment vector between ground and excited state of single molecules by the Stark effect

“…Since the detection efficiency of our setup is around 10 −3 , as determined previously, [23] we can relate the coincidence histograms, for the given time frame, directly to a correlation function [24] . The correlation function for photons can be found by solving the optical Bloch equations with the Laplace transform (see derivation in section 2 of Supporting Information), where we ignored contributions from the triplet state, which only adds photon bunching at longer timescales.…”

Luminescence enhancement by deuterium

“…Interestingly, the study of perdeuterated polycyclic aromatics (like [ 2 H 12 ] perylene, 2) and their luminescence properties continues even today. 32…”

“…Although there was not complete agreement among these investigators with their different experimental conditions, deuteration at the phenanthrene 9‐positon ( 1 , Figure 1) seemed to have the greatest effect on luminescence lifetime. Interestingly, the study of perdeuterated polycyclic aromatics (like [ 2 H 12 ] perylene, 2 ) and their luminescence properties continues even today 32 …”