Application of leaves derived biochars into counter electrode in dye-sensitized solar cells

摘要

Four biochars, which were obtained by one-step pyrolysis of leaves, were employed as catalytic materials for counter electrodes in dye-sensitized solar cells (DSCs). The leaves that were involved were pine needles, camphor leaves, firry leaves and red after-wood leaves. The results show that the remaining weight of the pine needles, camphor leaves, firry leaves and red after-wood leaves are respectively 9.49, 12.45, 10.39 and 10.96%. The pore size in the biochar derived from camphor leaves has an obvious bimodal distribution, with both macrospores (up to 10 μm) and mesopores (2～6nm), which is main reason for higher catalytic activities of biochar than graphite through providing more active sites. The S_(BET) of the biochar is 186.3 cm~2/g. The conversion efficiency (η) of each biochar based DSC is higher than that of graphite based one. Moreover, the camphor leaves derived biochar used in DSCs shows the maximum efficiency values in the four biochars.