[C70] Fullerene-sensitized triplet–triplet annihilation upconversion

Abstract

We herein report the first instance of using pristine C₇₀ as a heavy-atom free organic sensitizer for efficient triplet–triplet annihilation upconversion (UC) for both green-to-blue and red-to-green UC using 9,10-bis(phenylethynyl)anthracene and perylene as acceptors, respectively. C₇₀ achieved quantum yields of 8% and 0.8% for green-to-blue and red-to-green UC, 25 to 35 times higher than C₆₀, and showed improved stability under continuous laser irradiation compared to the benchmark platinum(II)-octaethylporphyrin.