“…A plethora of colorimetric sensors have been applied to detect environmental pollutants [ 7 , 8 ], toxic agents [ 9 , 10 , 11 ], biomarkers, and pharmaceutical- and food-relevant molecules [ 12 , 13 , 14 ]. Along this line, several reviews have been published [ 15 , 16 , 17 , 18 , 19 ]. Various detection systems can provide the readout of colorimetric sensors, including simple visual color interpretations, hand-held reading devices [ 20 , 21 ], commercial spectrometers [ 22 , 23 ], custom embedded systems [ 24 , 25 ], and complementary metal-oxide semiconductor (CMOS) chips embedded in commercial cameras and smartphones [ 15 , 26 , 27 , 28 , 29 , 30 ].…”