Polymer planar microcavities with CdSe‐ZnS core‐shell quantum dots for label‐free vapor sensing

Volatile organic compounds are a class of widespread air pollutants that are increasingly impacting anthropized environments. Due to the potential toxic effects associated with many of these compounds, the development of inexpensive and effective sensors for in situ detection, both indoor and outdoor, is of paramount technological importance to mitigate human exposure and develop appropriate intervention strategies. However, portable technologies are typically designed to quantify known pollutants, while qualitative measurements often require complex sampling and laboratory analyses. In this study, we propose a dual-detection photonic sensor based on polymeric microcavities doped with emitting nanocrystals, capable of identifying various volatile compounds in vapor phase. The sensor consists of a lattice of altenated sub-micrometric layers of cellulose acetate and poly(N-vinylcarbazole), with a periodic structure interrupted by an engineered defect layer doped with core-shell CdSe/ZnS quantum dots. The response to different analytes can be detected through both transmittance and photoluminescence measurements, with distinct features arising from the specific chemical and physical interactions between the sensor components and the pollutants.