Development of Optical Sensors Based on Luminescent Transition-Metal Complexes

Luminescence-based optical sensors are becoming increasingly important particularly in the area of fibber optic sensors. Most luminescence sensors detect analyses based on the change in luminescent intensity or excited-state lifetime of the sensing material as a function of analyst concentration. Luminescent materials with long excited-state lifetime are essential for the development of inexpensive sensors because it is much simpler and less expensive to measure lifetime in microseconds than in nanoseconds. Luminescent dyes with absorption in the visible region would allow the use of inexpensive light sources such as light emitting diodes (LEDs). Recent studies indicate that luminescent transition metal complexes, especially those with platinum group metals, have desirable spectral characteristics and features including long excited state lifetimes, high luminescence quantum yields and intense visible absorptions. They also tend to be thermally, chemically and photochemically robust. We have been investigating new luminescent sensor materials with the aims to understand the behaviour of luminescent materials in polymer and gel support and to develop new sensor materials with desirable properties.