Visible and Long-Lasting Chemiluminescence System for Dual Colorimetric and Chemiluminescent Humidity Monitoring

Chemiluminescence (CL) is widely used in environmental monitoring, biological assays, and bioimaging due to its high sensitivity and low background interference. However, conventional CL systems suffer from low luminous efficiency, rapid luminescence decay, and the need for catalytic activation and strong oxidants. Herein, we present a unique CL system, operated in DMSO/EtOH (9/1, v/v) solvent mixture, which exhibits three advantages: (1) strong and visible CL, (2) long-lasting luminescence (lasting up to 30 min), and (3) catalyst-free operation. In this CL system, NaOH reacts with oxygen to generate hydroxyl radicals (^•OH), which subsequently oxidize luminol to produce CL. We further developed a dual-mode colorimetric and CL sensing platform for water detection by integrating a pH-sensitive probe (<i>E</i>)-2-(2-(2-(7-bromo-4-oxo-4H-chromen-3-yl)-vinyl)-6-methyl-4<i>H</i>-thiochromen-4-ylidene) malononitrile (<b>DCCBr</b>), and replacing NaOH with water-responsive sodium peroxide (Na₂O₂). Incorporating this CL system into a DMSO-EtOH organogel prolonged the CL duration to up to 24 h, enabling continuous monitoring of humidity.