Measurement of Luminescence Decays: Methods and Instrumentation
by Dr. Mark Sulkes
Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA.
Developments in electronics, PMT technology, and excitation light sources have contributed to improvements in luminescence decay detection. The result in recent years has been more precise determination of lifetimes, particularly in the sub-ns regime, at often drastically reduced costs. The most important factor in cost reduction, also affording some enhanced capabilities, has been the development of numerous LED and laser diodes, spanning a wide wavelength range, that can provide sub-ns pulses and can be driven even to GHz frequencies. The cost of these light sources is typically a small fraction of conventional laser systems. The result in the lowest cost regime (waveform digitizer combined with LED/laser diode excitation sources) is a rather good and potentially quite inexpensive system for determining strong emission luminescence lifetimes from multi-ns to µs. This review is particularly concerned with time and frequency domain methods that are capable of more precise lifetimes in the ns to the sub-ns regime. These capabilities have been available for several decades at fairly significant costs. The advent of LED/laser diode excitation sources has greatly lowered the cost of these capabilities and even afforded some performance enhancements, particularly in the frequency domain. Powerful commercial instrumentation is available at much-reduced cost. User implemented or improved, systems at a further reduced cost are increasingly feasible.
