单步热解竹叶生物炭的特征及其DSSC的光电性能研究

One-step pyrolysis of bamboo derived biochar and its photovoltaic performance as counter electrode in dye-sensitized solar cell

以竹叶为原料经单步热解获得生物炭,在分析生物炭的形貌、孔隙和晶体结构等特征的基础上,将其作为对电极催化材料引入染料敏化太阳电池(DSSC),并将其与活性炭和石墨进行对比。结果表明:生物炭是一种具有三级孔隙结构的富碳材料,比表面积为19.73cm2/g。三级孔隙的主要尺寸为20nm、150nm和1~5μm,其中少量的宏观孔隙具有取向性。生物炭中的碳元素主要以类石墨微晶堆积而成的无定型碳形式存在。生物炭的上述特征使其具有较优异的催化活性和较强的氧化还原对扩散能力,相应器件的光电性能远优于石墨,且与活性炭相当,三者器件的转换效率依次为2.44%、0.77%和2.09%。

The biochar was first prepared through one-step pyrolysis with bamboo leaves as raw material,and then applied as catalytic material in counter electrode for dye-sensitized solar cell（DSSC）based on the characteristic analyses of biochar,such as morphology,pore structure and crystal structure.Results showed that the biochar derived from bamboo leaves was a carbon-rich material with 3-level pore structures and a specific surface area of 19.73cm^2/g.The sizes of 3-level pore structures mainly distributed around 20 nm,150nm and between 1~5μm,and some macropores showed an orientation structure.The carbon in the biochar was mostly in the form of amorphous carbon composed of the stacks of graphene sheets.These characteristics endowed the biochar with excellent catalytic activity and diffusion ability of redox couple.As a result,the biochar based DSSC possessed photovoltaic properties far superior to the graphite based one,and comparable with the activated carbon based one.The conversion efficiency of DSSC with charcoal,graphite,activated carbon as catalytic material were 2.44%,0.77%,2.09%,respectively.