Improvement of Photovoltaic Performance and Long-Term Stability of CdSe/CdS Quantum Dot@N719 Dye-Sensitized Tandem Solar Cells

In this work, we fabricated a novel photoanode based on CdSe/CdS at SnO2 core/shell nanoparticles to achieve highly efficient quantum dots (QDs) and dye-sensitized tandem solar cells. For the CdSe/CdS at SnO2 at N719 device, a SnO2 nanolayer first avoids CdSe/CdS QDs corrosion in the electrolyte (EL) and second collects the electrons from its surrounding N719 and CdSe/CdS core and transfers them to the front FTO electrode. Photovoltaic performance test shows that this design can effectively enhance the stability of the cell. During up to 32 days of testing, short-circuit current
${J}_{\text {sc}}$
is not attenuated, and open-circuit voltage
${V}_{\text {oc}}$
gradually increases, resulting in the observable improvement of photoelectric conversion efficiency of devices. An optimal power conversion efficiency (PCE) of 5.43% is achieved for tandem solar cells.