Chemical Sensors
We have shown how the self-charge transfer complexes (SCTCs) of a single-component organic conjugate can be used in chemical sensing applications. Exposing a solid-state device built using TLC plates coated with the conjugate to dichloromethane (analyte) vapors switches the device’s RTP emission color from yellow to red under excitation by a 365 nm UV lamp. The systems can be quickly switched back to the original state by exposing the device to warm air. Further, exposing of nitrogen gas to the aqueous buffer solution of the conjugate for a few seconds changes the original weekly intense orange emission under excitation by a UV lamp (365 nm) to a bright red RTP emission. This red emission can be reverted back to the original state by purging of molecular oxygen. This property of the conjugate enables quick, selective and efficient detection of the analyte via interplay of triplet state in the red-region of the spectrum. We are currently looking into ways to take advantage of this novel SCTCs and NIR-IR-SCTCs in bio-imaging of hyperoxia and hypoxia applications.
Mechano-sensors
The modularity and dual emission via TADF and RTP of the naphthalene appended quinolone-carbazole conjugates allowed us to use them as mechano-luminescent emitter. We have shown that how non-centric phase of one of the conjugate that show prompt and RTP at ambient conditions can be transformed to its centric phase that exhibits dual TADF and RTP features. We have revealed that modulation of higher-lying triplet (T2) energy caused by mechanical effect is responsible for such intriguing effect. We intend to use these sterically hindered systems for further development of mechano-phosphors.
