Non-Technical: There is a growing need for small-size chemical and biological sensors to enable their integration into existing and developing technologies such as wearable electronics. The proposed research will address this need by developing such compact, sensitive, reliable, eventually user-friendly, inexpensive, flexible, and field-deployable sensors. In the long run the sensors will be adapted for applications such as medical testing, water and food quality monitoring, and security inspection. In addition to advancing the vital (bio) chemical sensing field, the project will benefit society by educating students in a diverse and highly interdisciplinary environment, producing highly qualified scientists/engineers who will contribute to this important multifaceted field, addressing key challenges in materials and device designs. The success of the project is expected to significantly advance the fields of thin film flexible electronics in conjunction with life-saving analytical applications.
The specific goal of the proposed research is to advance the development of compact, sensitive, reliable, eventually user-friendly, inexpensive, flexible, and field-deployable, integrated photoluminescence (PL)-based chem/bio sensors, including in multiple analyte arrays. This objective addresses the growing need for continued miniaturization of sensors in applications such as medical testing, water and food quality monitoring, and security inspection. Moreover, such small-size sensors will enable their integration into existing and developing technologies, e.g., wearable electronics. To accomplish the objective of the proposed research fundamental science and engineering research is required. Thin film¡Vbased microcavity organic light emitting diodes (mcOLEDs) will be used as optical excitation sources; they will be integrated with hybrid, perovskite-based photodetectors (PDs). The mcOLEDs will be fabricated combinatorially on a single substrate, providing narrow emission bands (full width half max FWHM~20 nm). The emission peaks, produced by different active materials and microcavity dimensions, will range from the red to the near UV. The uniform dense array of such mcOLEDs, yet unachieved, will be integrated with two types of highly responsive perovskite PDs (an approach not yet explored): those responsive over a broad spectral range and those responsive over a narrow range. Bio/chem analytes will be monitored in two modes of operation, measuring analyte-induced changes in the (i) PL intensity using narrow-band PDs and (ii) PL decay time using both PD types. Developing both approaches will enhance selectivity and specificity. Importantly, to enable the advantageous PL monitoring where viable, the mcOLEDs and PDs will be evaluated and optimized to shorten the pulsed electroluminescence (EL) decay time and the PDs¡¦ response time by fundamental studies of their relation to materials, charge mobility, layer structures and thickness, defects, and device design. The integrated compact sensors will be demonstrated for two array types: (i) those operated by monitoring PL for, e.g., O2, dissolved O2, glucose, lactate, cholesterol, and ethanol, and (2) those operated largely by monitoring IPL as in e.g., pH measurement and immunoassays, which are of biological and health monitoring importance. The approaches outlined in this proposal will pave the way to miniaturized analytical tools on flexible substrates, integrated with microfluidic architectures. Array designs, attribute optimization, the demonstrated applications, and initial exploration of flexible devices are expected to significantly advance the fields of organic and hybrid electronics and analytical methodologies.
