A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

Aoibhín A Cullen; Katharina Heintz; Laura O'Reilly; Conor Long; Andreas Heise; Robert Murphy; Joshua Karlsson; Elizabeth Gibson; Gregory M Greetham; Michael Towrie; Mary T Pryce

doi:10.3389/fchem.2020.584060

A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

Front Chem. 2020 Oct 19:8:584060. doi: 10.3389/fchem.2020.584060. eCollection 2020.

Affiliations

¹ School of Chemical Sciences, Dublin City University, Dublin, Ireland.
² Department of Chemistry, Royal College of Surgeons in Ireland, Dublin, Ireland.
³ Energy Materials Laboratory, Department of Chemistry, School of Natural and Environmental Science, Newcastle University, Newcastle upon Tyne, United Kingdom.
⁴ Central Laser Facility, Science & Technology Facilities Council, Research Complex at Harwell, Rutherford Appleton Laboratory, Oxford, United Kingdom.

Abstract

A novel 4,4-difuoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) copolymer with diethynylbenzene has been synthesised, and its ability to act as a photosensitiser for the photocatalytic generation of hydrogen was investigated by time-resolved spectroscopic techniques spanning the ps- to ns-timescales. Both transient absorption and time-resolved infrared spectroscopy were used to probe the excited state dynamics of this photosensitising unit in a variety of solvents. These studies indicated how environmental factors can influence the photophysics of the BODIPY polymer. A homogeneous photocatalytic hydrogen evolution system has been developed using the BODIPY copolymer and cobaloxime which provides hydrogen evolution rates of 319 μmol h^-1 g^-1 after 24 h of visible irradiation.

Keywords: BODIPY polymer; TAS; TRIR; hydrogen; photocatalytic; time-resolved spectroscopy.