Tunable perovskite-based photodetectors in optical sensing

Broad- and narrow-band, tunable perovskite photodetectors (PPDs) with size-dependent fast response times are demonstrated for the first time in optical sensing of analytes, including gas-phase and dissolved oxygen (DO), as well as glucose. The sensors included a LED excitation source and a polystyrene film with embedded oxygen-sensitive dyes, PtOEP or PdOEP. The analyte's dose-dependent photoluminescence (PL) intensity I and decay time τ were measured. Using the PPDs enabled monitoring gas-phase O2 at levels of 0 %–100 % with a sensitivity comparable to that of a Si photodiode. A broad dynamic range was similarly observed for DO monitoring and the limit of detection for glucose monitoring was ∼0.02 mM at an initial level of ∼0.26 mM DO. Importantly, the size-dependent fast response time of the PPDs enabled analyte monitoring via the preferred measurement of τ, rather than I, over a broad dynamic range, which was unattainable with organic photodetectors. The use of the narrow-band PPDs eliminated the need for optical filters, which leads to more compact device designs