Performance of V_2O_3@C composites via a sol-gel precursor assisted by soluble starch as Pt-free counter electrodes for dye sensitized solar cells

摘要

The traditional counter electrodes (CEs) catalysts are mainly noble Pt-based materials, but their scarcity and high cost impede their practical applications, especially in dye sensitized solar cells (DSSCs). Hence, identifying Pt free catalyst materials for CEs have been regarded as one of the crucial steps to improve energy conversion efficiency and cost effectiveness of DSSCs. Herein, a feasible one-step reduction was put forward to prepare V2O3@C composites utilizing V2O5 as metal sources, and the soluble starch as carbon source. The four V2O3@C composite catalysts have successfully been prepared and further were applied to CEs as catalytic materials in the encapsulation of DSSCs. The power conversion efficiencies (PCE) of 2.79, 3.94, 5.13 and 4.97% were respectively obtained from mass ratios of the soluble starch to V2O5 with 1:2, 1:1, 2:1 and 4:1 as counter electrode for the regeneration of I-3(-)/I- redox couples. The enhanced performance can be ascribed to the number of active catalytic sites and the distribution channels on the V2O3@C composites CEs, which was caused by that the larger surface area and higher conductivity of amorphous C from the pyrolyzed carbonization of the soluble starch in the precursor.