Quantum dots/silicon nanowire coaxial photoelectrode-based dye-sensitized solar cells

In this study, we propose a novel dye-sensitized solar cell (DSSC) structure that employs a quantum dot/semiconductor silicon (QD/Si) coaxial nanorod array to replace the conventional dye/TiO₂/TCO photoelectrode. We replaced the backlight input mode with top-side illumination and used a quantum dot to replace dye as the light-absorbing material. Photon-excited photoelectrons can be effectively transported to each silicon nanorod and conveyed to the counter electrode. We use two-stage metal-assisted etching (MAE) to fabricate the micro-nano hybrid structure on a silicon substrate. We then use the chemical bath deposition (CBD) method to synthesize a Sb₂S₃ quantum dot on the surface of each silicon nanorod to form the photoelectrode for the quantum dot/semiconductor silicon coaxial nanorod array. We use a xenon lamp to simulate AM 1.5 G (1000 W/m₂) sunlight. Then, we investigate the influence of different silicon nanorod arrays and CBD deposition times on the photoelectric conversion efficiency. When an NH (N-type with high resistance) silicon substrate is used, the QD/Si coaxial nanorod array synthesized by three runs of Sb₂S₃ deposition shows the highest photoelectric conversion efficiency of 0.253%. The corresponding short-circuit current density, open-circuit voltage, and fill factor are 5.19 mA/cm², 0.24 V, and 20.33%, respectively.