Reversible Ultralong Organic Phosphorescence for Visual and Selective Chloroform Detection

Area of Science:

• Materials Science
• Chemical Sensing
• Organic Chemistry

Background:

• Volatile organic compounds (VOCs) pose significant risks to human health and the environment.
• Developing sensitive and selective visual detection systems for VOCs remains a challenge.

Purpose of the Study:

• To develop a metal-free organic molecule with ultralong organic phosphorescence (UOP) for visual detection of VOCs.
• To investigate the potential of 2,4-di(10 H-phenothiazin-10-yl)-1,3,5-triazine (TDP) as a selective chemical probe for chloroform.

Main Methods:

• Synthesis and characterization of the metal-free organic molecule TDP.
• Investigation of TDP's photophysical properties, specifically its ultralong organic phosphorescence (UOP).
• Exposure of TDP to chloroform vapor and analysis of changes in UOP intensity and lifetime.

Main Results:

• TDP exhibits a green UOP with a long lifetime (56 ms) in its pristine solid state.
• Exposure to chloroform significantly diminishes TDP's UOP, indicating detection.
• The probe demonstrates high sensitivity (detection limit as low as 5 ppm), excellent selectivity, and good repeatability for chloroform.

Conclusions:

• TDP serves as a highly effective visual chemical probe for selective chloroform detection.
• The space confinement via intermolecular interactions between chloroform and TDP is crucial for selectivity.
• This work expands the application of UOP-based organic luminogens in chemical sensing.