On the Quantum Yield of Photon Upconversion via Triplet–Triplet Annihilation

Zhou, Yan; Castellano, Felix N.; Schmidt, Timothy W.; Hanson, Kenneth

doi:10.1021/acsenergylett.0c01150

Cited by 177 publications

(244 citation statements)

References 38 publications

(61 reference statements)

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“…The UC emission of the ternary NR-ACA-DPA UC system will manifest as emission from the DPA after the TTA-UC process has occurred. Therefore, taken from the absorbance maximum of the sensitizer and the emission maximum of the annihilator, the apparent anti-Stokes shift of the system presented here is 0.82 eV, 41 which is comparable to recently reported red-to-blue QD sensitized UC schemes. 31,42 The ligand exchange process occurs through the addition of ACA in chlorobenzene and allowing the solutions to stir overnight.…”

Section: Resultssupporting

confidence: 86%

“…Here, we choose to normalize the UC quantum yield by two, as TTA is a two-photon to one process, meaning the upper limit of the UC quantum yield (QY) is 50%. 41 The uc was calculated according to Castellano and coworkers, 1 where the absorbance and UC emission of the NR-ACA-DPA system was compared to that of rubrene, which is shown in Figure S7, in accordance to Equation 2.…”

Section: Resultsmentioning

confidence: 99%

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Red-to-Blue Photon Upconversion Enabled by One Dimensional CdTe Nanorods

VanOrman¹,

Conti²,

Strouse³

et al. 2020

Preprint

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Photon upconversion via triplet-triplet annihilation creating light in the high energy regime of the visible spectrum could prove particularly useful in applications such as photocatalysis. Quantum-confined semiconductor nanocrystals have previously been shown to function as efficient triplet sensitizers in green-to-blue upconversion schemes, but an improvement in the apparent anti-Stokes shift of the upconversion scheme will be beneficial for future commercial applications. Additionally, both zero- and two-dimensional quantum-confined sensitizers have been investigated, but not one-dimensional nanomaterials. In this work, we fill a hole in the present field of photon upconversion by accomplishing both of these feats. Specifically, we introduce CdTe nanorods as a new class of triplet sensitizers for red-to-blue photon upconversion. When the triplet transmitter ligand (9-anthracenecarboxylic acid) and triplet annihilator (9,10-diphenylanthracene) are added to the nanorods, we observe efficient photon upconversion at a normalized upconversion efficiency of huc = 4.3% and a low threshold power of Ith = 93 mW/cm2. The introduction of one-dimensional triplet sensitizers could yield future research that effectively harnesses the unique properties of these materials allowing for new approaches for efficient photon upconversion, especially at large apparent anti-Stokes shifts.

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Section: Resultssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Red-to-Blue Photon Upconversion Enabled by One Dimensional CdTe Nanorods

VanOrman¹,

Conti²,

Strouse³

et al. 2020

Preprint

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“…The ms‐scale delayed emission supports the triplet‐mediated mechanism (Supporting Information, Figure S6). The theoretical maximum of TTA‐UC efficiency η UC is standardized to 100 % [39] . The η UC value of Ir(C6) 2 (acac) and TIPS‐Nph was determined as 20.5 % by the relative method (Figure 2 b, see the Supporting Information for details).…”

Section: Figurementioning

confidence: 99%

“…The theoretical maximum of TTA-UC efficiency h UC is standardized to 100 %. [39] The h UC value of Ir(C6) 2 (acac) and TIPS-Nph was determined as 20.5 % by the relative method (Figure 2 b, see the Supporting Information for details). The reliability of the high h UC was confirmed by a similar value of 21.4 % at 17 Wcm À2 obtained by the absolute method in the integrating sphere (see the Supporting Information for details).…”

Section: Triplet-triplet Annihilation-based Photon Upconversionmentioning

confidence: 99%

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

et al. 2020

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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.

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“…The TTA-UC efficiency ηUC is standardized to a theoretical maximum of 100%. 39 The ηUC value of Ir(C6)2(acac) and TIPS-Nph was determined as 20.5% by the relative method ( Figure 2b, see SI for details). The reliability of the highest ηUC was confirmed by a similar value of 21.4% at 17.2 W cm −2 obtained by the absolute method in the integrating sphere (see SI for details).…”

mentioning

confidence: 99%

TIPS-Naphthalene for Efficient Visible-to-UV Photon Upconversion under Sunlight and Room Light

Harada¹,

Sasaki²,

Hosoyamada³

et al. 2020

Preprint

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Until now, the efficiency of triplet-triplet annihilation-based photon upconversion (TTA-UC) from visible to ultraviolet (UV) light has been limited to ca. 10% due to the absence of high-performance acceptors (emitters). Here, we present the first example of visible-to-UV TTA-UC internal efficiency ηUC beyond 20% by developing a novel UV emitter, 1,4-bis((triisopropylsilyl)ethynyl)naphthalene (TIPS-Nph), and sensitizing its triplet by a donor Ir(C6)2(acac) with strong visible absorption and weak UV absorption. Under optimized conditions, 97% of the excitation light is absorbed, the threshold excitation intensity (Ith = 1.1 mW cm−2) is lower than the solar irradiance (1.4 mW cm−2 for 445 ± 5 nm), and significantly, the highest external UC efficiency ηUC,ext of 17.4% for vis-to-UV TTA-UC is achieved. Upconverted UV emission can also be obtained with weak light sources such as an AM 1.5 solar simulator and room LEDs, paving the way for a variety of solar and indoor applications.

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On the Quantum Yield of Photon Upconversion via Triplet–Triplet Annihilation

Cited by 177 publications

References 38 publications

Red-to-Blue Photon Upconversion Enabled by One Dimensional CdTe Nanorods

Red-to-Blue Photon Upconversion Enabled by One Dimensional CdTe Nanorods

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

TIPS-Naphthalene for Efficient Visible-to-UV Photon Upconversion under Sunlight and Room Light

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