聚合物/富勒烯太阳能电池形貌优化研究

Research of Morphology Optimization of Novel Polymer/Fullerene Organic Solar Cells

选用苯并二噻吩和噻吩并吡咯(PBDTTPD)作为给体材料,和经典的受体材料富勒烯衍生物PC61BM/PC71BM搭配制作如下器件结构:氧化铟锡导电玻璃ITO(160nm)/阳极修饰层PEDOT:PSS(40nm)/活性层PBDTTPD:PCBM(90nm)/阴极修饰层LiF(0.5nm)/金属阴极Al(120nm).采用溶剂退火和添加剂后处理方法,利用有机溶剂慢蒸发过程以及溶剂和添加剂不同的沸点,使得给体和受体材料完成自组装,形成有序的给受体互联贯穿网状结构.结果表明,溶剂退火可以极大地优化PBDTTPD:PCBM活性层的形貌,最高能量转换效率(Power Conversion Effciency,PCE)达到4.95%.该实验成果可以为进一步提高聚合物/富勒烯有机太阳能电池的效率,提供有力的理论依据和实验指导.

Highly efficient PBDTTPD-based photovoltaic devices with the configuration of Indium tin oxide（ITO）/poly（3,4-ethylenedioxythiophene）-poly（styrenesulfonate）（PEDOT∶PSS）/PBDTTPD∶methanofulle rene（6,6）-phenyl-C61/-butyric acid methyl ester（PC61BM）/LiF（0.5nm）/Al（100nm）,are realized with ortho-dichlorobenzene（oDCB）solvent annealing treatment.It is revealed that the best photovoltaic device is obtained when the blend ratio of PBDTTPD∶PC61BM is 1∶2and it is processed with oDCB solvent annealing for 12 hours.The short circuit current density（Jsc）and power conversion efficiency（PCE）value are measured to be 10.91mA/cm2 and 4.95%respectively,which are both higher than the counterparts treated with chlorobenzene（CB）solvent annealing or a processing additive（1%-3% v/v,chloronaphthalene）.Atomic force microscopy measurements of the active layer after the solvent annealing treatment are carried out.The phase separation length scale of the PBDTTPD∶PC61BM（1∶2）layers is comparable to the exciton diffusion length when the active layer is treated by oDCB solvent annealing,which facilitates effective exciton dissociation and carrier diffusion in the active layer.Therefore,highly efficient PBDTTPD-based photovoltaic devices can be achieved with oDCB solvent annealing,which indicates that the performance of polymer solar cells（PSCs）can probably be improved by improving the phase segregation and penetrative networks of donor and acceptor blends.