Black TiO2-Based Dual Photoanodes Boost the Efficiency of Quantum Dot-Sensitized Solar Cells to 11.7%

Abstract

Quantum dot−sensitized solar cells (QDSSC) have been regarded as one of the most promising candidates for effective utilization of solar energy, but its power conversion efficiency (PCE) is still far from meeting expectations. One of the most important bottlenecks is the limited collection efficiency of photogenerated electrons in the photoanodes. Herein, we design QDSSCs with a dual−photoanode architecture, and assemble the dual photoanodes with black TiO2 nanoparticles (NPs), which were processed by a femtosecond laser in the filamentation regime, and common CdS/CdSe QD sensitizers. A maximum PCE of 11.7% with a short circuit current density of 50.3 mA/cm2 is unambiguously achieved. We reveal both experimentally and theoretically that the enhanced PCE is mainly attributed to the improved light harvesting of black TiO2 due to the black TiO2 shells formed on white TiO2 NPs.

Revealing the Impact of Alkaline Agents on the Photocatalytic Characteristics of Black Titanium Dioxide (TiO2)

“…It is revealed that the synthesis of black TiO 2 introduced some defects in the crystal structure, and Ti 3+ can be seen at 458.6 and 464.2 eV, respectively . The peak at 530.4 eV is evidence for the Ti–O linkage, and the peak located at 532.7 eV is attributed to the availability of oxygen vacancies . The results indicate that the as-synthesized black TiO 2 has a large number of Ti 3+ defects and oxygen vacancies.…”

“…34 The peak at 530.4 eV is evidence for the Ti−O linkage, and the peak located at 532.7 eV is attributed to the availability of oxygen vacancies. 35 The results indicate that the as-synthesized black TiO 2 has a large number of Ti 3+ defects and oxygen vacancies.…”