Effects of Electrolytes on the Photocurrent of N‐Annulated Perylene‐Sensitized Photoelectrochemical Cells Based on NiO as Photocathode

Abstract

AbstractThe new organic dye NPP with N‐annulated perylene (NP) as donor, bithiophene as π bridge and perylenemonoimide (PMI) as acceptor has been synthesized and applied for dye‐sensitized photoelectrochemical cells (DSPEC). Phosphate (PBS), sodium sulfate (Na2SO4) and acetate buffer solution (ABS) have been employed as electrolytes to investigate their effects on the photocurrent of the DSPEC. After 200 s illumination, PBS, ABS and Na2SO4 based cells exhibited a photocurrent of −13, −7 and −7 μA cm−2, respectively. Electrochemical impedance spectroscopy (EIS) indicated that the DSPEC device with PBS as electrolyte showed the smallest charge transfer resistance (Rct) and largest hole lifetime, which might best explain the highest photocurrent found for the PBS based device. In addition, incident monochromatic photon‐to‐electron conversion efficiency (IPCE) of the photoelectrochemical cells with PBS, ABS and Na2SO4 aqueous solution as electrolytes was determined. The IPCE of the PBS based device was the highest at 430∼620 nm and the result was consistent with the measured photocurrent. However, under long‐time illumination, the acetate buffer solution based device displayed the highest stability. Hence, the results show that the electrolytes have a significant effect on the photocurrent and stability of DSPECs.