Photon upconversion in multicomponent systems: Role of back energy transfer.
J Chem Phys
; 153(11): 114302, 2020 Sep 21.
Article
em En
| MEDLINE
| ID: mdl-32962369
ABSTRACT
Photon upconversion based on sensitized triplet-triplet annihilation in bi-component systems is a multistep process that involves a triplet-triplet energy transfer (ET) from a donor to an acceptor moiety. This is aimed at sensitizing the population of annihilating optically dark triplets that generates the high energy photoluminescence. A large resonance between the involved triplets is usually recommended because it increases the energy gain between absorbed and emitted upconverted photons. However, it also enables efficient back-ET from acceptor to donor triplets, with potential detrimental consequences on the system performance. Here, we analyze a model system, where the energy difference between donor and acceptor triplets is lower than kBT at room temperature by means of time resolved and steady state photoluminescence spectroscopy, and develop a kinetic model, which describes the iterative loop that transfers the triplet exciton between the donor and acceptor molecules. In such a way, we obtained the guidelines for the optimization of the system composition required to overcome the back-ET effect and maximize the upconversion quantum yield.
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Coleções:
01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article