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

• Published in: Advanced optical materials 2020-10, Vol.8 (20), p.n/a
• Main Authors: Mak, Chun Hong, Liu, Rugeng, Han, Xu, Tang, Yunqi, Zou, Xingli, Shen, Hsin‐Hui, Meng, Yao, Zou, Guizheng, Hsu, Hsien‐Yi
• Format: Article
• Language: English
• Subjects: Electrochemical cells; Electrochemiluminescence; Emitters; Excitons; Heavy metals; Materials science; molecular design; Optics; Optoelectronics; Organic semiconductors; Organometallic compounds; organometallic emitters; Phosphorescence; phosphorescent devices, electrochemiluminescence devices; Platinum; thermally activated delayed phosphorescence
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202001023

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. The platinum‐based organometallic triplet emitter, PPtTPtP, exhibits highly efficient dual and blueshifted phosphorescence induced by thermally activated delayed photoluminescence and interchromophore exciton interaction in H‐aggregates respectively for the application of electrochemiluminescence (ECL) devices. The SIT‐route of ECL process, including energy sufficient singlet route, intersystem crossing, and triplet relaxation, is first reported in this work.