Modulation of photoluminescence and solar thermal energy storage in norbornadiene–quadricyclane dimers

The norbornadiene/quadricyclane (NBD/QC) photoswitch pair is a promising system for molecular solar thermal (MOST) energy storage. Multichromophoric systems with two or more photoswitches can offer red-shifted absorption, higher energy densities, and additional functionality. Here, a series of ortho...

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Detalles Bibliográficos
Autores: Salthouse, Rebeca Jane|||0000-0003-2213-6956, Elholm, Jacob Lynge, Cortellazzi, Irene, Hölzel, Helen, Ferreira, Pedro Miguel Mendonça, Fernandez, Lorette Sylvie Jacqueline|||0000-0002-6776-7359, Hetherington, Jack, Moth-Poulsen, Kasper|||0000-0003-4018-4927
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/450683
Acceso en línea:https://hdl.handle.net/2117/450683
https://dx.doi.org/10.1002/anie.202516629
Access Level:acceso abierto
Palabra clave:Fluorescence
Norbornadiene–quadricyclane
Photoswitches
Solar energy storage
Thermal energy releas
Àrees temàtiques de la UPC::Enginyeria química::Química física::Estructura molecular
Àrees temàtiques de la UPC::Enginyeria química::Química física::Termoquímica
Àrees temàtiques de la UPC::Enginyeria química::Química física::Cinètica
Àrees temàtiques de la UPC::Enginyeria química::Química orgànica::Compostos orgànics
Descripción
Sumario:The norbornadiene/quadricyclane (NBD/QC) photoswitch pair is a promising system for molecular solar thermal (MOST) energy storage. Multichromophoric systems with two or more photoswitches can offer red-shifted absorption, higher energy densities, and additional functionality. Here, a series of ortho- and para-substituted NBD dimers bearing methoxy, hexoxy (for solubility), and cyano groups were synthesised and evaluated for their MOST properties. Compared to monomers, the dimers display red-shifted absorption and improved solar spectrum match, with onsets between 448–488 nm, owing to their donor–acceptor design and extended conjugation. A key finding is the tunable relationship between molecular structure, photoluminescence and photoisomerisation: para-dimers exhibit efficient fluorescence, whilst ortho-dimers are superior photoswitches with quantum yields of isomerisation, Fi, up to 63%. Solvent choice further modulates behaviour; Fi is higher in acetonitrile, whereas fluorescence is more efficient in toluene. This interplay allows tailoring for specific functions. The best-performing photoswitches were studied in a liquid-chip device, achieving a record solar conversion efficiency of 2.9%. Catalytic back-conversion using cobalt phthalocyanine on carbon and macroscopic heat release experiments at 0.1 M yielded a 5.78 °C temperature increase. This first experimental macroscopic heat release of a dimeric system provides important insights into design challenges and opportunities for advancing multichromophoric systems towards MOST applications.