Laser-engineered black rutile TiO2 photoanode for CdS/CdSe-sensitized quantum dot solar cells with a significant power conversion efficiency of 9.1 %

The research deals with fabrication of CdS/CdSe-sensitized quantum dot sensitized solar cells (QDSSCs) with laser-engineered black rutile TiO2 nanoparticles (TiO2-NPs) as the photoanode material. Three QDSSC devices with pristine and two types of black rutile TiO2-NPs engineered respectively in water and ethanol by intense femtosecond laser propagating in the filamentation regime were prepared in the same architecture. Extremely different power conversion efficiencies (PCE) of 1.43 %, 3.68 % and 9.11 %, in which the black TiO2-NPs-based devices show respectively a two-fold and six-fold PCE higher than the pristine TiO2-NPs, were obtained. The absorption and electrochemical impedance spectroscopy analyses revealed that the device with the highest PCE has the highest absorption efficiency in the wide spectral range from UV to mid-infrared and shunt resistance (Rsh) of 1364.9 omega, but the smallest series resistance (Rs) of 190.3 omega, which are attributed to the surface modi-fication on the structural and optical properties of TiO2-NPs by femtosecond laser pulses.

Automated summary

The research focuses on the fabrication of CdS/CdSe-sensitized quantum dot sensitized solar cells (QDSSCs) using laser-engineered black rutile TiO2 nanoparticles (TiO2-NPs) as the photoanode material. The results show that the devices based on black TiO2-NPs have significantly higher power conversion efficiency (PCE) compared to those using pristine TiO2-NPs. Analysis of absorption and electrochemical impedance spectroscopy indicates that the device with the highest PCE has the highest absorption efficiency in a wide spectral range and the smallest series resistance, which can be attributed to the surface modification of TiO2-NPs by femtosecond laser pulses.