NPB阳极缓冲层对反型结构聚合物太阳能电池性能的影响

Effects of NPB anode buffer layer on the performances of inverted bulk heterojunction polymer solar cells

制备了给体材料为poly(3-hexylthiophene)(P3HT),受体材料为[6,6]-phenyl-C60-butyric acid methyl ester(PCBM),器件结构为ITO/ZnO/P3HT:PCBM/NPB(0,1,5,10,25 nm)/Ag的反型体异质结聚合物太阳能电池.不同厚度的N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine(NPB)阳极缓冲层被用来改善器件性能,研究了NPB阳极缓冲层对器件特性的影响.研究发现,1 nm厚的NPB改善了器件的载流子收集效率,增加了器件的短路电流与开路电压.当NPB缓冲层的厚度达到25 nm时,过厚的NPB导致串联电阻增加,使得器件特性大幅下降.通过电容-电压测试,进一步研究了不同厚度NPB对器件载流子注入与收集的影响,1 nm厚的NPB修饰并没有改善器件的载流子注入但是增加了器件对光生载流子的收集效率,过厚的NPB使得自由载流子的复合占据主导.适合厚度的NPB可以作为一种阳极缓冲层材料应用于聚合物太阳能电池提高器件特性.

Inverted configuration bulk heterojunction polymer solar cells based on ITO/ZnO/P3HT：PCBM/NPB/Ag were fabricated, with the donor material being poly（3-hexylthiophene）（P3HT）, and the acceptor material being [6, 6]-phenyl- C60-butyric acid methyl ester（PCBM）. N, N＇-diphenyl-N, N＇-bis（l-naphthyl）-l, l＇-biphenyl-4, 4＇-diamine（NPB） thin anode buffer layers with different thicknesses, which were used to improve the performances of the devices; and the effects of NPB anode buffer were investigated. The insertion of 1 nm thick NPB improves charge collection of the device, both of the short circuit current and open circuit voltage are enhanced. When the thickness of NPB reaches 25 nm, the series resistances are significantly increased, leading to reduced device performances. Effects of different thicknesses of NPB on charge injection and collection are investigated by capacitance-voltage measurements. NPB with 1 nm thickness improves charge collection of the device but without improving charge injection, and the charge recombination mechanism is dominant if the NPB layer is too thick. NPB thin layer with appropriate thickness could be used to enhance the performances of bulk heterojunction polymer solar cells.