Heterogeneous Integration of Thin-Film Organic and Inorganic Devices for Optical Based Bioelectrical and Chemical Sensing

Directly visualizing electrical and chemical signals via optical approaches is an effective and powerful method for analyzing biological activities in a remote and high-throughput manner. Here we develop a heterogeneously integrated optoelectronic sensor that optically monitors the changes of bioelectrical and biochemical signals. Fabricated via epitaxial liftoff and transfer printing, the thin-film, microscale sensor combines a photodiode and a light-emitting diode (LED) made of inorganic III-V compound semiconductor heterostructures, as well as an organic electrochemical transistor (OECT). Ascribed to the matching condition among the heterogeneously integrated components, luminescent emissions of the sensor, which can be captured with a fluorescence microscope, dynamically respond to input electrical signals and are systematically characterized. Through voltage dependent luminance variations, the device optically records synthesized electrocardiography (ECG) signals with peak amplitudes from 100 mV to 10 mV. Furthermore, the integrated sensor is capable of selectively detecting calcium variations when immersing into the aqueous solution. The integrated sensor combines the advantages of inorganic and organic semiconductors and offers opportunities to wirelessly detect biological activities at a large scale.