Carbon dot / thermo-responsive polymer capacitive wavelength-specific photodetector

Raz jelinek, ben gurion univeristy, beer sheva, Israel (razj@bgu.ac.il)

Organic photodetectors are considered attractive alternatives to inorganic, semiconductor-based devices. We constructed a wavelength-specific capacitive photodetector, comprising carbon dots (C-dots) and poly-(N-isopropylacrylamide) (PNIPAM), a thermo-responsive polymer. Upon illuminating the C-dot/PNIPAM composite, light absorbed by the C-dots is released as heat; the photothermal effect gives rise to a rapid temperature increase consequently affecting structural transformation of the PNIPAM host and concomitant change in the recorded capacitance. Importantly, wavelength sensitivity of the photodetector is determined by the excitation wavelength of the embedded C-dots; we show that tuning the wavelength response of the system can be readily achieved through selection of the C-dot species incorporated within the PNIPAM matrix. The C-dot/PNIPAM photodetector exhibits reversibility and rapid light response, is synthesized from inexpensive and recyclable building blocks.