Molecularly Dispersed Donors in Acceptor Molecular Crystals for Photon Upconversion under Low Excitation Intensity

Masanori Hosoyamada, Nobuhiro Yanai, Taku Ogawa, Nobuo Kimizuka

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

For real-world applications of photon upconversion based on the triplet-triplet annihilation (TTA-UC), it is imperative to develop solid-state TTA-UC systems that work effectively under low excitation power comparable to solar irradiance. As an approach in this direction, aromatic crystals showing high triplet diffusivity are expected to serve as a useful platform. However, donor molecules inevitably tend to segregate from the host acceptor crystals, and this inhomogeneity results in the disappointing performance of crystalline state TTA-UC. In this work, a series of cast-film-forming acceptors was developed, which provide both regular acceptor alignment and soft domains of alkyl chains that accommodate donor molecules without segregation. A typical triplet sensitizer, PtII octaethylporphyrin (PtOEP), was dispersed in these acceptor crystals without aggregation. As a result, efficient triplet energy transfer from the donor to the acceptor and diffusion of triplet excitons among regularly aligned anthracene chromophores occurred. It resulted in TTA-UC emission at low excitation intensities, comparable to solar irradiance. Overcoming donor aggregation: A long-standing problem of aromatic-crystal-based photon upconversion (UC), donor aggregation in the acceptor crystal, is solved herein by modifying the acceptor with multiple alkyl chains. This improved the donor-to-acceptor energy-transfer efficiency, leading to effective UC processes even at low excitation intensities comparable to solar irradiance (see figure).

Original languageEnglish
Pages (from-to)2060-2067
Number of pages8
JournalChemistry - A European Journal
Volume22
Issue number6
DOIs
Publication statusPublished - Feb 5 2016

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Molecular crystals
Photons
Crystals
Agglomeration
Energy transfer
Molecules
Anthracene
Chromophores
Excitons
Crystalline materials

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

Cite this

Molecularly Dispersed Donors in Acceptor Molecular Crystals for Photon Upconversion under Low Excitation Intensity. / Hosoyamada, Masanori; Yanai, Nobuhiro; Ogawa, Taku; Kimizuka, Nobuo.

In: Chemistry - A European Journal, Vol. 22, No. 6, 05.02.2016, p. 2060-2067.

Research output: Contribution to journalArticle

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