不同厚度的活性层及阴极的改变对聚合物太阳电池性能的影响

Influence of the thickness and cathode material on the performance of the polymer solar cell

以MEH-PPV(poly(2-methoxy-5-(2′-ethylhexoxy)-1,4-phenylene vinylene))为电子给体材料,PCBM(1-(3-methoxycarbonyl)-propyl-1-1-phenyl-(6,6)C61)为电子受体材料,制成了共混体系太阳电池.研究了不同厚度活性层对太阳电池性能的影响.结果表明,活性层厚度为100nm时,太阳电池具有最佳性能.活性层厚度的增加,增大了光生电荷的复合,减少了太阳电池的填充因子,从而减少了太阳电池的能量转换效率.分析了活性层较厚的太阳电池在光照下J-V曲线中出现S形的原因.探讨了阴极的改变对太阳电池性能影响.结果表明,阴极为LiF/Al时,太阳电池阴、阳两极能形成欧姆接触,有利于电荷的收集,增大了活性层中电荷的传输动力和太阳光的吸收,提高了太阳电池性能.

The solar cells based on the blend of MEH-PPV（ poly（2-methoxy-5-（2′-ethylhexyloxy）-1,4-phenylene vinylene）） and PCBM （ 1-（ 3-methoxycarbonyl ）-propyl-1-1-phenyl-（ 6,6 ） C61 ） as acceptor were fabricated. The thickness dependence of the performance of solar cells was studied. The results showed that the solar cells with active layer thickness of 100 nm have the best performance. Increasing device thickness resulted in an increase of charge recombination and a lowering of the fill factor,which leads to lower overall power conversion efficiency. The reasons for the S-shaped kink in the thick device were also analyzed. Influence of the cathode material on the performance of the devices was discussed. The results showed that the solar cells using LiF /Al as the negative electrode formed ohmic contacts at the cathode and anode,which favored the collecting of the charge,increased the transmission of the charge and the absorption of solar light,and improved the performance of the solar cell.