Optical gating with organic building blocks. A quantitative model for the fluorescence modulation of photochromic perylene bisimide dithienylcyclopentene triads

Abstract

We investigated the capability of molecular triads, consisting of two strong fluorophores that were covalently linked to a photochromic molecule, for optical gating. Therefore we monitored the fluorescence intensity of the fluorophores as a function of the isomeric state of the photoswitch. From the analysis of our data we develop a kinetic model that allows us to predict quantitatively the degree of the fluorescence modulation as a function of the mutual intensities of the lasers that are used to induce the fluorescence and the switching of the photochromic unit. We find that the achievable contrast for the modulation of the fluorescence depends mainly on the intensity ratio of the two light beams and appears to be very robust against absolute changes of these intensities. The latter result provides valuable information for the development of all-optical circuits which would require to handle different signal strengths for the input and output levels.

A trident dithienylethene-perylenemonoimide dyad with super fluorescence switching speed and ratio

“…The photons as information carriers are comprehensively investigated and promising in information technology with demands on bandwidth and information density 8,9 . Organic molecular switches may provide potential capability to applications in transmit, modulate and detect light or photons.…”

“…Alternatively, fluorescent spectroscopy exhibiting high sensitivity provides another method to characterize the photoswitching properties of DTEs, which requires those DTEs that display both photochromism and fluorescence switching. Evidently, fluorescence switching is more promising than photochromism in all-optical switches and transistors [7][8][9] . A great deal of efforts have been taken to develop novel photoswitchable fluorescent DTE derivatives with high fluorescence quantum yields (F F ), on/off ratios and switching speeds [10][11][12][13][14][15][16] .…”

Deliberate Switching of Single Photochromic Triads

“…In a series of publications we have studied quantitatively the optical switching behaviour of ensembles of molecular triads consisting of two perylene bisimide (PBI) units that are covalently linked to a 1,2-bis(2-methyl-5-phenyl-3-thienyl)-perfluorocyclopentene (DCP) unit, using a phenyl bridge 26 27 28 29 . In this study, we employ a new triad in which the bridge is a biphenyl unit (see inset on the left hand side of Fig.…”

“…1 . The design strategy of this triad, PBI-DCP-PBI, combines the favourable properties of the photoswitchable DCP units - high photoreaction quantum yields (only about 100 photons per molecule are needed for the photocyclization, and about 2000 photons per molecule for the photocycloreversion reaction, respectively 28 ), and high fatigue resistance - with the superior fluorescence properties of the perylene derivatives 1 30 31 32 . In particular the involvement of the strong fluorophore PBI is favourable for combining these approaches with single-molecule techniques which might open new avenues for biosensing with ultimate sensitivity, ultra-high density optical data storage (one bit - one molecule), or super-resolution fluorescence imaging 33 34 35 36 37 .…”

Enantiospecific photoresponse of sterically hindered diarylethenes for chiroptical switches and photomemories

“…Chiral molecules and helical structures exist universally in nature, and are of vital importance to living systems 1 2 . Owing to the clean and precise spatiotemporal control in a remote and noninvasive manner, the light-driven chirality transformation, especially based on photochromic systems 3 4 , enables a myriad of potential applications in smart materials 5 6 7 8 9 and functional bio-switches 10 11 12 at molecular level. Amongst the most ideal candidates, diarylethenes (DAEs) 13 14 15 16 17 18 19 undergo reversible conrotatory 6 π -electron photocyclization and cycloreversion, along with excellent thermal irreversibility and outstanding fatigue resistance.…”