Insights into enhanced electrochemiluminescence of a multiresonance thermally activated delayed fluorescence molecule

Abstract

The electrochemiluminescence (ECL) behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time by means of ECL-voltage curves, newly designed ECL-time observatory, and ECL spectroscopy. The compound, Mes 3 DiKTa, shows complex ECL

Elucidation of an Aggregate Excited State in the Electrochemiluminescence and Chemiluminescence of a Thermally Activated Delayed Fluorescence (TADF) Emitter

“…More recently, several reports have documented organic long-persistent luminescent compounds whose luminescence decays in the order of seconds. , The long-lived luminescence in this class of emitters originates from charge separation, followed by a slow charge recombination route, often in a framework of electron-donating and electron-accepting molecules to facilitate the formation of charge-separated states . This phenomenon has been reported for photoluminescent materials (OLPL), but also recently by us for electrochemiluminescence (OLECL). , In particular, there is evidence that the compounds that exhibit organic long-persistent luminescence often possess aggregate excited states …”

“…40 This phenomenon has been reported for photoluminescent materials (OLPL), 41 but also recently by us for electrochemiluminescence (OLECL). 16,42 In particular, there is evidence that the compounds that exhibit organic longpersistent luminescence often possess aggregate excited states. 43 Recently, the synthesis and photophysical properties of a series of through-space charge transfer thermally activated delayed fluorescence compounds 4,4′-(1,2-dihydroacenaphthylene-5,6-diyl)bis(N,N-diphenylaniline) (TPA-ace-TRZ) (Figure 1A), 4-(1,2-dihydroacenaphthylen-5-yl)-N,N-diphenylaniline (TPA-ace) (Figure 1B), 6-(4-(diphenylamino)phenyl)-1,2-dihydroacenaphthylene-5-carbonitrile (TPA-ace-CN) (Figure 1C), and 4,4′-(1,2-dihydroacenaphthylene-5,6diyl)bis(N,N-diphenylaniline) (2TPA-ace) (Figure 1D) were first investigated by us.…”

“…Electrochemiluminescence (ECL) involves the electro-generation of radical species that subsequently undergo electron transfer reactions to form excited states, which release photons upon relaxation. , ECL has many analytical applications including biological immunoassays, − analyte detection, , single-molecule detection, ,− and various imaging application, , along with various luminophores. ,,− Since ECL does not require an incident light source, detection can be achieved with excellent signal-to-noise ratio and sensitivity . There are two general pathways by which ECL can occur.…”

“… 40 This phenomenon has been reported for photoluminescent materials (OLPL), 41 but also recently by us for electrochemiluminescence (OLECL). 16 , 42 In particular, there is evidence that the compounds that exhibit organic long-persistent luminescence often possess aggregate excited states. 43 …”

Studies on Annihilation and Coreactant Electrochemiluminescence of Thermally Activated Delayed Fluorescent Molecules in Organic Medium

“…To date, some progress has been achieved in the topic of TADF-ECL, such as the achievements of highly efficient TADF-ECL in organic medium [ 18 , 19 , 29 , 30 , 31 ], extremely narrow ECL spectra [ 32 ], reliable TADF-ECL in aqueous medium [ 12 , 33 ] and TADF-ECL sensing applications [ 19 , 34 ]. In 2014, Ishimatsu et al reported the first annihilation TADF-ECL, in which a TADF molecular 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) [ 35 ] was used as the ECL luminophore in organic medium [ 18 ].…”