Photochemical Upconversion Light Emitting Diode (LED): Theory of Triplet Annihilation Enhanced by a Cavity

Abstract

Artificial lighting is a widespread technology which consumes large amounts of energy. Triplet-triplet annihilation photochemical upconversion is a method of converting light to a higher frequency. Here, it is shown theoretically that photochemical upconversion can be applied to Watt-scale lighting, with performance closely approaching the 50% quantum yield upper limit. The dynamic equilibrium of an efficient device consisting of an LED, an upconverting material, and an optical cavity is described from optical and thermal perspectives.

Photochemical Upconversion Theory: Importance of Triplet Energy Levels and Triplet Quenching

“…As illustrated in Fig. 2, we simulate a device consisting of a solar cell, an anabathmophore layer which performs photochemical upconversion [12], and a Lambertian diffuse reflector [4]. Our simulations use random samples from the AM1.5G solar spectrum.…”

“…The utility comes from the spontaneous increase in the energy per photon. Owing to its exothermic nature, photochemical upconversion can be relatively efficient [7,10,12,13].…”

Halide Perovskites: A Progress Report on Photon Interconversion

“…As the perovskite's optoelectronic properties are influenced by dimensionality, we will highlight current work on photon interconversion applications using 3D bulk and quantum confined perovskite‐based materials, as well as an overview of 2D perovskite‐inspired materials. Furthermore, we will provide insight into the current gaps in literature and hope to stimulate the field of photon interconversion which can open novel strategies and help mature this emerging field and its applications in photovoltaics (PVs), [ 1–4 ] luminescent solar concentrators (LSCs), [ 5 ] light‐emitting diodes (LEDs), [ 6,7 ] lasers, photocatalysis, [ 8–10 ] imaging, [ 11–13 ] sensing, [ 14 ] and communication technologies.…”

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the field of photon interconversion which can open novel strategies and help mature this emerging field and its applications in photovoltaics (PVs), [1][2][3][4] luminescent solar concentrators (LSCs), [5] light-emitting diodes (LEDs), [6,7] lasers, photocatalysis, [8][9][10] imaging, [11][12][13] sensing, [14] and communication technologies.In general, photon interconversion relates to processes which change the wavelength of the emitted light upon irradiation with a gain in photon energy (UC processes), or a splitting of the incident photon energy to create multiple photons (downconversion processes). Schematics of the two different photon interconversion mechanisms which are discussed in this report are shown in Figure 1.UC processes such as triplet-triplet annihilation (TTA) or lanthanide-based UC can aid in harvesting the low energy portion of the solar spectrum for PVs [1,15] and infrared imaging applications, improve in-vivo biomedical imaging [12,13] or create the required high energy photons desired in photocatalytic processes without detrimental photobleaching effects.

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“…the field of photon interconversion which can open novel strategies and help mature this emerging field and its applications in photovoltaics (PVs), [1][2][3][4] luminescent solar concentrators (LSCs), [5] light-emitting diodes (LEDs), [6,7] lasers, photocatalysis, [8][9][10] imaging, [11][12][13] sensing, [14] and communication technologies.…”