CdSe/ZnS (Core/Shell) Quantum Dots Multi-wallled Carbon Nanotubes (MWCNTs) on a Stainless Steel as a Photoanode in Solar Cells

摘要

Multi-walled carbon nanotube (MWCNT) forests grown on a stainless steel substrate were used as a photoanode in CdSe/ZnS (core/shell) quantum dot (QD) sensitized solar cells (QDSSCs). QD-treated MWCNTs on the conductive metal stainless substrate showed a higher power conversion efficiency (PCE) of 0.014% than those grown on a doped silicon substrate with a PCE of 0.005% under AM 1.5 sunlight intensity (100 mW/cm~2). This higher efficiency can be attributed to the lower sheet resistance of 0.0045 Ω/sq for the metal substrate than the value of 259 Ω/sq for doped silicon. Additionally, the relationship between the reflectance of as-grown CNT and PCE is also examined. QDSSC fabricated from CNT of lower reflectance of 1.9% at a height of 25 μm showed a better efficiency because the lower reflectance indicates the scattering of light repeatedly into deeper CNT forest resulting in higher absorption which indicates a higher surface area of CNTs to adsorb much amount of QDs on CNT forests, resulting in the higher PCE.