Sara Mattiello, Andrew Danos, Kleitos Stavrou, Alessandra Ronchi, Roman Baranovski, Domenico Florenzano, Francesco Meinardi, Luca Beverina, Andrew Monkman, Angelo Monguzzi
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引用次数: 0
Abstract
Triplet–triplet annihilation (TTA), or triplet fusion, is a biexcitonic process in which two triplet-excited molecules can combine their energy to promote one into an excited singlet state. To alleviate the dependence of the TTA rate and yield on triplet diffusion in both solid and solution environments, intramolecular TTA (intra-TTA) has been recently proposed in conjugated molecular systems able to hold multiple triplet excitons simultaneously. Developing from the previous demonstration of TTA performance enhancement in sensitized upconversion solutions, here similar improvements in triplet harvesting in solid-state films are reported under electrical excitation in organic light emitting diodes (OLEDs). At low dye concentration and low current densities, the intra-TTA active OLED shows a +40% improved external quantum efficiency with respect to the reference device, and a TTA spin-statistical factor f4DPA of 0.4, close to that determined in fluid solution for the individual chromophore (0.45). These results therefore indicate the utility of this molecular design strategy across a wider range of TTA applications, and with particular utility in the further development of low-power TTA-enhanced OLEDs.
期刊介绍:
Advanced Optical Materials, part of the esteemed Advanced portfolio, is a unique materials science journal concentrating on all facets of light-matter interactions. For over a decade, it has been the preferred optical materials journal for significant discoveries in photonics, plasmonics, metamaterials, and more. The Advanced portfolio from Wiley is a collection of globally respected, high-impact journals that disseminate the best science from established and emerging researchers, aiding them in fulfilling their mission and amplifying the reach of their scientific discoveries.