Discovery of Key TIPS-Naphthalene for Efficient Visible-to-UV Photon Upconversion under Sunlight and Room Light*

Naoyuki Harada; Yoichi Sasaki; Masanori Hosoyamada; Nobuo Kimizuka; Nobuhiro Yanai

doi:10.1002/anie.202012419

Discovery of Key TIPS-Naphthalene for Efficient Visible-to-UV Photon Upconversion under Sunlight and Room Light*

Angew Chem Int Ed Engl. 2021 Jan 4;60(1):142-147. doi: 10.1002/anie.202012419. Epub 2020 Nov 24.

Authors

Naoyuki Harada¹, Yoichi Sasaki¹, Masanori Hosoyamada¹, Nobuo Kimizuka¹, Nobuhiro Yanai^{1

2}

Affiliations

¹ Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
² PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan.

PMID: 33063410
DOI: 10.1002/anie.202012419

Abstract

While many studies have been done on triplet-triplet annihilation-based photon upconversion (TTA-UC) to produce visible light with high efficiency, the efficient TTA-UC from visible to UV light, despite its importance for a variety of solar and indoor applications, remains a challenging task. Here, we report the highest visible-to-UV TTA-UC efficiency of 20.5 % based on the discovery of an excellent UV emitter, 1,4-bis((triisopropylsilyl)ethynyl)naphthalene (TIPS-Nph). TIPS-Nph is an acceptor with desirable features of high fluorescence quantum yield and high singlet generation efficiency by TTA. TIPS-Nph has a low enough triplet energy level to be sensitized by Ir(C6)₂ (acac), a superior donor that does not quench UV emission. The combination of TIPS-Nph and Ir(C6)₂ (acac) realizes the efficient UV light production even with weak light sources such as an AM 1.5 solar simulator and room LEDs.

Keywords: LED; TIPS-naphthalene; UV light; photon upconversion; triplet-triplet annihilation.

Abstract

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