Glucose-derived porous carbon as a highly efficient and low-cost counter electrode for quantum dot-sensitized solar cells

Abstract

Biomass-derived porous carbon is widely used in supercapacitors, carbon dioxide capture and lithium–sulfur batteries owing to its advantages such as wide sources, low cost and good stability. However, it is rarely used in quantum dot-sensitized solar cells (QDSCs). Here, glucose-derived porous carbon was obtained by hydrothermal carbonization followed with high-temperature KOH activation, and employed as an efficient counter electrode (CE) for QDSCs. The CV, EIS and Tafel-polarization analysis showed that porous carbon exhibits excellent catalytic activity for reduction of S_n²⁻. The CE based on porous carbon activated at 900 °C (C₉₀₀) presents best performance with interface charge transfer resistance (R_ct) of 2.4 Ω cm² due to the synergy between high graphitization degree and large specific surface area. The power conversion efficiency (PCE) of the QDSCs assembled with a CdS/CdSe sensitized TiO₂ photoanode and the C₉₀₀ CE is up to 5.61% under one sun illumination. The excellent catalytic activity of C₉₀₀ is attributed to its large specific surface area and porous structure and high degree graphitization. This suggests that glucose-derived porous carbon can become a potential low-cost and efficient CE material for QDSCs.