Green-to-Blue Triplet Fusion Upconversion Sensitized by Anisotropic CdSe Nanoplatelets

VanOrman, Zachary A.; Bieber, Alexander S.; Nienhaus, Lea

doi:10.1021/acs.chemmater.0c01354

Cited by 44 publications

(63 citation statements)

References 73 publications

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“…A wide variety of materials classes for use as triplet sensitizers have been reported, ranging from metal-organic complexes with strong spin-orbit coupling, [4,19,20,22,[26][27][28][29][30][31] conventional semiconductor quantum dots (QDs)" [32][33][34][35][36][37][38][39][40] two-dimensional CdSe nanoplatelets, [41] perovskite-based QDs, [17,21,42,43] transition metal dichalcogenides, [44,45] two-dimensional perovskites [46] to bulk three-dimensional perovskites. [47][48][49][50][51] In the following, we will focus on the methylammonium formamidinium lead triiodide (MAFA) bulk perovskite sensitization of triplet states in the organic semiconductor rubrene by charge transfer.…”

Section: Introductionmentioning

confidence: 99%

One‐Step Fabrication of Perovskite‐Based Upconversion Devices

et al. 2020

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Device fabrication methods for applications in upconversion processes using perovskite thin films have suffered from reproducibility and scalability issues, which prevent the upscaling of this technology. In this contribution, we developed a perovskite‐based upconversion device approach where the triplet annihilator is added in situ to the antisolvent and investigated the effect of the device fabrication procedure on the properties of our device. By comparing the properties of a device based on our new fabrication approach with the existing bilayer procedure, we seek to shed light on the underlying optoelectronic processes influenced by the different fabrication methods, while further advancing possible device architectures for upconversion devices. Device characterization by optical methods, X‐ray diffraction and atomic force microscopy revealed that the in situ fabricated devices match the performance or even outcompete our previously developed bilayer devices while significantly simplifying the device fabrication. In particular, we find that the developed one‐step fabrication technique enables intercalation of the upconverting layer into the perovskite film prior to annealing, resulting in a larger interface thus, more efficient charge extraction.

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Section: Introductionmentioning

confidence: 99%

One‐Step Fabrication of Perovskite‐Based Upconversion Devices

et al. 2020

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“…The point at which these regimes meet gives the threshold intensity value Ith, which is a figure of merit for the power density at which the TTA-UC process becomes efficient. For the system with the most efficient TTA-UC, at an ACA concentration of 0.04 mM ACA, an Ith value of 93 mW/cm 2 was determined, which is considerably lower compared to many other quantum confined semiconductor sensitized systems, 12,15,17,28,29,36,48 especially those that exhibit red-to-blue UC. 31,42 Only the upconverted emission follows this unique power dependence and the excitonic NR emission exhibits the expected linear regime at all powers, shown in Figure S6.…”

Section: Resultsmentioning

confidence: 79%

“…QDs and 2D CdSe nanoplatelets. 17 From the Stern-Volmer plot (with concentrations < 0.10 mM ACA), we extract a bimolecular quenching constant of 8.82 x 10 12 M -1 S -1 (See Supporting Information for more information). Above a concentration of ~ 0.15 mM ACA, a saturation of the quenching is observed, which is highlighted in Figure 3d by a gray box.…”

Section: Resultsmentioning

confidence: 99%

“…PL lifetimes were collected by TCPSC as detailed previously. 11,17,50 Lifetimes were measured under 520 nm excitation at a repetition frequency of 1 MHz. Photon arrival times were histogrammed by a MultiHarp 150 (PicoQuant) at a single photon counting avalanche diode (Micron Photon Devices).…”

Section: Time-correlated Single Photon Counting (Tcspc)mentioning

confidence: 99%

“…Additionally, we observe a power threshold for efficient UC of Ith = 93 mW/cm 2 , which is considerably lower than the majority of systems utilizing quantumconfined triplet sensitizers. 17,25,31,36 Most importantly, we open the door to a new frontier of triplet sensitizer materials in the form of 1D semiconductor nanocrystals.…”

Section: Introductionmentioning

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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Efficient Visible‐to‐UV Photon Upconversion Systems Based on CdS Nanocrystals Modified with Triplet Energy Mediators

Hou

Olesund

Thurakkal

et al. 2021

Adv Funct Materials

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Developing high-performance visible-to-UV photon upconversion systems based on triplet-triplet annihilation photon upconversion (TTA-UC) is highly desired, as it provides a potential approach for UV light-induced photosynthesis and photocatalysis. However, the quantum yield and spectral range of visible-to-UV TTA-UC based on nanocrystals (NCs) are still far from satisfactory. Here, three different sized CdS NCs are systematically investigated with triplet energy transfer to four mediators and four annihilators, thus substantially expanding the available materials for visibleto-UV TTA-UC. By improving the quality of CdS NCs, introducing the mediator via a direct mixing fashion, and matching the energy levels, a high TTA-UC quantum yield of 10.4% (out of a 50% maximum) is achieved in one case, which represents a record performance in TTA-UC based on NCs without doping. In another case, TTA-UC photons approaching 4 eV are observed, which is on par with the highest energies observed in optimized organic systems. Importantly, the in-depth investigation reveals that the direct mixing approach to introduce the mediator is a key factor that leads to close to unity efficiencies of triplet energy transfer, which ultimately governs the performance of NC-based TTA-UC systems. These findings provide guidelines for the design of high-performance TTA-UC systems toward solar energy harvesting.

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Green-to-Blue Triplet Fusion Upconversion Sensitized by Anisotropic CdSe Nanoplatelets

Cited by 44 publications

References 73 publications

One‐Step Fabrication of Perovskite‐Based Upconversion Devices

One‐Step Fabrication of Perovskite‐Based Upconversion Devices

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

Efficient Visible‐to‐UV Photon Upconversion Systems Based on CdS Nanocrystals Modified with Triplet Energy Mediators

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