Highly efficient photochemical upconversion in a quasi-solid organogel

Despite the promise of photochemical upconversion as a means to extend the light-harvesting capabilities of a range of photovoltaic solar energy conversion devices, it remains a challenge to create efficient, solid-state upconverting materials. Until now, a material has yet to be found which is as efficient as a liquid composition. Here, a gelated photochemical upconversion material is reported with a performance indistinguishable from an otherwise identical liquid composition. The sensitizer phosphorescence lifetime, Stern–Volmer quenching constants and upconversion performance (6% under one-sun illumination) were all found to be unchanged in a quasi-solid gelated sample when compared to the liquid sample. The result paves the way to a new family of efficient photochemical upconversion materials comprised of macroscopically solid, but microscopically liquid gel, for application in photovoltaics and photocatalytic water-splitting.