Thermally Activated Delayed Phosphorescence and Interchromophore Exciton Coupling in a Platinum‐Based Organometallic Emitter

Abstract

electrochemical properties of the constituent materials as well as intra-and intermolecular interactions. Molecular self-assembly in π-conjugated systems is essential because it opens up an avenue to organic materials with desired spectroscopic properties and electrochemical activities. [1] While organic π-conjugated structures have been considerably studied, the exploration of aggregates or gels containing metalorganic materials is relatively rare. [2] Platinum emitters produce long-lived and phosphorescent 3 π,π* triplet excited states caused by heavy-atom-induced spin-orbital coupling; [3] the device performance could be dramatically improved by the insertion of metal centers into organic semiconductors. [4] Therefore, the triplet emitter, which structurally feature a four-coordinated square planar platinum(II) center with the chemical structure P−CC−Pt(PBu 3) 2 −CC−T− CC−Pt(PBu 3) 2 −CC−P (PPtTPtP, where T = 2,5-thienylene and P = phenyl), is investigated to explore the photophysical and electrochemical properties. The organic-based molecules, as the most common organic dyes and supramolecules in the ECL device have been extensively studied in the past decade. [5] The ECL is a phenomenon that involves the annihilation of radical ions generated The comprehension of triplet exciton mechanisms in organic-inorganic semiconductors has a significant impact on emerging optoelectronic and biosensing technologies. The capability to mutually integrate the photophysical properties of conjugated organic semiconductor with those of well-characterized heavy metals is therefore of utmost importance. Due to heavy-atom effect, the platinum-based triplet emitter, PPtTPtT, achieves highly efficient phosphorescence. Here, it is first demonstrated that π-conjugated PPtTPtT organometallics in electrochemiluminescence (ECL) devices exhibit precisely dual and blueshifted phosphorescence simultaneously induced by thermally activated delayed phosphorescence (TADP) and interchromophore exciton interaction in H-aggregates. Utilizing a combination of photophysical and electrochemical techniques, the distinctive ECL process involving energy sufficient singlet route (S-route), intersystem crossing, as well as triplet relaxation, hereafter called SIT-route, is reported for the first time. The hybrid TADP materials designed with donor-acceptor-donor system enable potential applications, including but not limited to organic light-emitting diodes, light-emitting electrochemical cells, imaging devices, and other bio-related detections.

Recent progress on post-synthetic treatments of photoelectrodes for photoelectrochemical water splitting

“…In general, the enhanced photoactivity of hydrogenated TiO 2 can be ascribed to extra visible light absorption as well as to the optimized surface structures for reducing charge recombination and enhancing charge transfer. [131][132][133][134][135][136] By contrast, Mohajernia et al reported the annealing of TiO 2 in the Ar/H 2 atmosphere. 105 They found that the enhanced PEC performance should be dominantly attributed to strongly improved conductivity (i.e., semimetallic properties) as a result of the formation of O vac and Ti 3+ , and slightly due to the enhancement in light absorption.…”

Photoenhanced interfacial electron transfer of a dual functional hematite biophotoelectrode

“…Linear sweep voltammetry (LSV) at a potential range from À0.2 to 1 V vs. Ag/AgCl at a sweep rate of 10 mV s À1 was performed. [30][31][32] In a dark environment, consecutive cyclic voltametric (CV) measurements were conducted at a scan rate of 1 mV s À1 , with a potential window from À0.3 V to 0.5 V vs. Ag/AgCl. For an electrochemical kinetic study, a potential window from À1.1 V to 0.4 V vs. Ag/AgCl at different scan rates was used.…”

Lead-free hybrid perovskite photocatalysts: surface engineering, charge-carrier behaviors, and solar-driven applications

“…[35][36][37] With regards to the composition of hybrid perovskites, Cl, Br, I, and/or metal elements can be used for element doping to optimize the properties of perovskites. [38][39][40][41][42] Chen et al 43 have doped Mn 2+ and Yb 3+ into the perovskite structure, which has been reported to help induce additional dopant-related emission bands, leading to dual emissions. [44][45][46] The halide doping strategy can be employed to tune the bandgap value of perovskites.…”