Smartphone spectrophotometric techniques in NIR spectral vary. Different elements and photograph of ALS based mostly spectrophotometric system developed by Pereira et al., reproduced from Ref. with permission from plos.org. Schematic of the photometric system developed by Hussain et al. displaying the location of embedded ALS chip in a smartphone, reproduced from Ref. with permission from IEEE. Schematic of the smartphone spectroscopic system developed utilizing a DVD as a dispersive factor and the SEM picture of the DVD, reproduced from Ref. with permission from American Chemical Society. Smartphone spectroscopic techniques developed based mostly on fluorescence spectroscopy.