A Fused pH and Fluorescence Sensor Using the Same Sensing Area

Abstract

A fused pH and fluorescence sensor is proposed, and a prototype has been fabricated using a complimentary metal–oxide–semiconductor (CMOS) integrated circuit technology. In the proposed sensor, a charge-transfer-type pH sensor and a filter-less fluorescence detection sensor were fused, enabling the pH and the fluorescence intensity to be detected in the same pixel. In a simulation experiment using two light-emitting diodes (LEDs), the fluorescence intensity detected was 1/50 of the excitation light intensity. The dependence of the output signal on the pH was also investigated, and it was found that the pH sensitivity was 16 mV/pH.