Photoinitiated Energy Transfer in Porous‐Cage‐Stabilised Silver Nanoparticles

• Published in: Angewandte Chemie International Edition Vol. 62; no. 24; pp. e202303501 - n/a
• Main Authors: Wilms, Michael, Melendez, Lesly V., Hudson, Rohan J., Hall, Christopher R., Ratnayake, Samantha Prabath, Smith, Trevor, Gaspera, Enrico Della, Bryant, Gary, Connell, Timothy U., Gómez, Daniel E.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 12.06.2023
• Edition: International ed. in English
• Subjects: Cages; Composite materials; Composite structures; Energy Transfer; Nanoparticles; Plasmonics; Porosity; Porous Organic Cages; Porphyrins; Resonant interactions; Silver; Spectroscopy; Transient Absorption Spectroscopy; Water Splitting; Porous Organic Cages; Water Splitting; Energy Transfer; Plasmonics; Transient Absorption Spectroscopy
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202303501

We report a new composite material consisting of silver nanoparticles decorated with three‐dimensional molecular organic cages based on light‐absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano‐resonant interaction between the porphyrin Soret band and the nanoparticle‐localised surface‐plasmon resonance. Time‐resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited‐state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2‐fold current increase in photoelectrochemical water‐splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications. A new material containing plasmonic silver nanoparticles was synthesized using only porphyrin‐based porous organic cages as the ligand, which decorate the surface of the nanoparticle. The nanoparticle acts as a photosensitizer for the porphyrin cages by transferring its excited‐state energy to the porphyrin. The photosensitization effect and porosity of the ligand enable superior photoelectrochemical water splitting compared to the individual components.