High-sensitive hybrid photodetector based on CdSe quantum dots and graphene for detecting ATP bioluminescence on lab-on-chip devices

This work reports on a novel graphene-based bio-photon photodetector to detect ATP bioluminescent signal (550-570nm). The photocurrent response follows the absorbing spectra of the CdSe quantum dots (QDs), while graphene serves as the n-type charges transport channel. This study demonstrates that this kind of the photodetector has a responsivity of ~10⁵ A/W. Then, the photodetector is embedded into bottom layer of our previous lab-on-chip device to detecting the UTI E.coli cells in a vacuum chamber. The signals from the photodetector are collected by a detecting system. Different amounts of Escherichia coli had been measured by this photodetector. Results appear good linearity trend between the output of photodetector and number of the E.coli in a vacuum chamber, and show a resolution of 0.04 μA per 1.0*10^-5 CFU/mol variation in the concentration of E.coli. This study demonstrated the bio-photon photodetector based on CdSe QDs/graphene can be used to detect ATP bioluminescence.