Functionalized photonic crystal sensor elements based on nanoporous polymers

Abstract

We report the development of oxygen sensors using polymer photonic bandgap structures coupled with complementary metal oxide semiconductor (CMOS) integrated circuit chips. These integrated sensors, exploiting the porous sensing element, provide a new platform for the development of low cost, low powered, light weight, robust, and small sensors. In this paper, we demonstrate an approach to encapsulation of chemical and biological recognition elements within the porous structures. This sensing platform is built on our recently demonstrated nanofabrication technique using holographic interferometry of a photo-activated mixture that includes a volatile solvent as well as monomers, photoinitiators, and co-initiators. The resulting structure is a nanoporous polymer ID photonic bandgap structure that provides desirable optical reflection. These recognition elements can be directly integrated into optical sensor systems that we have previously developed. The optical sensor system is built using CMOS detectors that include phototransistors, a transimpedance amplifier, and other signal processing units. Specifically, we demonstrate a prototype oxygen sensor by encapsulating the fluorophore (tris(4,7-diphenyl-l, 10-phenathroline)rutheniurn(II) into the photonic bandgap structure and monitoring the fluorescence intensity. © 2008 Materials Research Society.