A Simple Circuit for Time-Resolved Luminescence (TRL) Measurement Instruments: Demonstration Through a Smartphone-Based TRL Imager for Anticounterfeiting Application

Time-resolved luminescence (TRL) measurement is a sensitive detection technique by eliminating sample autofluorescence, but TRL measurement instruments composed of multiple key components (e.g., a rapidly pulsed light excitation source, a time-gated optical detector, and a synchronization module aligning the timing between the light source and the detector) have been sophisticated, expensive, or bulky, which limits their point-of-care or in-field applications. To reduce the cost and complexity of these instruments, in this letter, we developed a simple circuit for rapid LED pulsing and accurate timing synchronization and implemented it in a compact TRL imager with a ultraviolet light emitting diode (UV LED) as a light source and a chopper-coupled smartphone camera as a time-gated optical detector. The TRL measurement of this imager using this circuit was successfully validated through an anticounterfeiting application. We believe that this simple circuit can be adopted in the development of low-cost and compact TRL measurement instruments for broad point-of-care or in-field applications.