Recent advances in triplet–triplet annihilation upconversion and singlet fission, towards solar energy applications

Abstract

Solar energy is an ample renewable energy resource, with photovoltaic (PV) technology enabling a direct route from light to electricity. Currently, PVs are limited in photon conversion efficiency, due in...

Triplet–triplet annihilation mediated photon upconversion solar energy systems

“…14 In this regard, triplet-triplet annihilation mediated photon upconversion (TTA-UC) is emerging as a promising photon upconversion process wherein two low-energy triplet excitons combine to form one high-energy singlet photon that can be infused into solar cells to overcome transmission losses. 15,16 Hence, TTA-UC has the potential to push the solar energy conversion limit to 44 %. 15 Similar to the PV systems, solar fuel systems in general and molecular solar thermal energy storage (MOST) systems in particular also face transmission losses due to the small absorption window of molecular systems used.…”

“…15,16 Hence, TTA-UC has the potential to push the solar energy conversion limit to 44 %. 15 Similar to the PV systems, solar fuel systems in general and molecular solar thermal energy storage (MOST) systems in particular also face transmission losses due to the small absorption window of molecular systems used. Practically fabricable and efficient MOST windows and chips could turn out to be a sustainable energy resource for the heating/cooling of houses and thermoelectric generators.…”

Perovskite-Sensitized Upconversion under Operando Conditions

“…Another unique emerging application for halide perovskites is solid-state photon upconversion (UC). − Incorporating UC devices into commercial solar technologies holds the potential to increase current PCEs by harvesting additional sub-band-gap photons. − Here, bulk perovskite semiconductors act as triplet sensitizers for near-infrared-to-visible photon UC via a triplet–triplet annihilation (TTA) mechanism at solar-relevant fluences. ,− Current perovskite-sensitized TTA-UC devices are generally composed of bilayer thin films (Figure a) and utilize rubrene or 1-chloro-9,10-bis­(phenylethynyl)­anthracene as the annihilator species where the perovskite sensitizes the triplet state of the organic semiconductor (OSC). − In bulk perovskite-sensitized TTA-UC devices, the perovskite absorbs incident near-infrared photons, generating free carriers due to the low exciton binding energy . The free electrons and holes in the perovskite conduction (CB) and valence bands (VB), respectively, are asynchronously transferred to the annihilator, rubrene, and recombine to generate the bound triplet state T 1 (Figure b).…”

Intramolecular singlet fission and triplet exciton harvesting in tetracene oligomers for solar energy conversion

“…37,51–61 These molecules have been summarized in some comprehensive reviews on this field. 7,53,62–65…”