A Polymer Dots-Based Photoelectrochemical pH Sensor: Simplicity, High Sensitivity, and Broad-Range pH Measurement

This work reported the photoelectrochemical (PEC) pH sensor for sensitive and broad-range pH measurement on the basis of semiconducting polymer dots (Pdots). The sensor was fabricated by immobilizing Pdots onto the surface of indium tin oxide (ITO). Experimental results revealed that the carboxylic acid groups of Pdots were sensitive to pH variation, which could result in conformational changes and further diffusion of carriers. Besides, different pH value could change the redox properties of the Pdots, and the photocurrent response was hence altered by the carriers produced on the Pdots. Further results demonstrated that the developed sensor exhibited variable photocurrent sensitively by responding to different pH values. This pH sensor is of high sensitivity, stability, and reversibility, which provides a bright prospect for future pH measurements in the bioanalytical field.