Fig. 6: Demonstration of device flexibility and chemical/bio-sensing.
From: Spectrum projection with a bandgap-gradient perovskite cell for colour perception
a An image of the flexible devices under UV illumination. b I–V curves of the flat and bent flexible device in the dark and at different wavelengths of light, respectively (bent radius is 5 mm). c Variations in the currents of the flexible device as a function of bending cycles at different wavelengths of light. d Scheme of applying the GBG device in chemical/bio-sensors, in which the chemical/bio-analytes (e.g., proton concentrations in solutions) result in colour changes of stimuli-responsive materials (e.g., pH testing papers), and the GBG device senses the stimuli with colour comparisons. Measurements of the colour responses to pH testing papers in solutions with different proton concentrations (i.e., pH values of 1, 3, 5, 7, and 9) with e a silicon photodiode, f a spectrometer, and g our GBG device (error bars in c and g are obtained from 5 measurements).
