An ultrastable Cu(I) cluster exhibiting TADF for ppm-level oxygen detection.

Cu(I) complexes for optical oxygen sensing have failed to achieve both high sensitivity and stability. Herein, we report an ultrastable Cu(I) cluster with outstanding oxygen sensing performance (KSV = 2024.50 bar-1 and LOD = 4.89 ppm). It retains 90% of its oxygen sensitivity after exposure to pH 1.24 and 13.96 solutions.