基于P3HT∶PCBM体异质结有机太阳电池的光老化

Photoaging of the Organic Solar Cells Based on P3HT∶PCBM Bulk Heterojunctions

使用聚-3已基噻吩(P3HT)和富勒烯衍生物(PCBM)作为给体和受体材料,并制备结构为ITO/PEDOT∶PSS/P3HT∶PCBM/Ca/Al有机太阳电池。采用自主搭建的光老化实验平台,一方面对有机太阳电池在空气氛围下的光老化性能进行深入地研究;另一方面忽略水和氧的影响,研究了在惰性气体的氛围下50 h的光老化实验。研究发现,相对于在惰性气体中光老化样品的开路电压没有变化,在空气中光老化样品的开路电压由0.63 V降低至0.58 V,这说明空气中水和氧对有机太阳电池性能有较大地影响;而在惰性气体下对有机太阳电池的实验表明,光老化后有机太阳电池的短路电流和能量转换效率显著降低,光电转换效率(IPCE)测试表明光老化后活性层光吸收能力也有明显地降低。扫描电子显微镜(SEM)和原子力显微镜(AFM)形貌研究揭示了其性能下降的主要原因,即光老化前后薄膜表面变化明显,方均根粗糙度明显变大是导致器件性能变差的主要原因。

The organic solar cells with ITO/PEDOT ： PSS/P3HT ： PCBM/Ca/A1 structure was fabricated by poly （3-hexylthiophene） （P3HT） and [-6,6] -phenyl-C61-butyric acid methylester （PCBM） as the donor and receptor materials. By using the self-built photoaging experiment plat- form, the photoaging performance of the organic solar cells was deeply investigated in the air, and the photoaging experiment was researched in an inert atmosphere for 50 h ignoring the effects of water and oxygen. The researches show that the open-circuit voltage of photoaged samples in the inert atmosphere does not change, whereas the open-circuit voltage of photoaged samples in the air decreases from 0.63 V to 0.58 V. These indicate that water and oxygen in the air havesignificantly effects on the performance of the organic solar cells. The experiment of the organic solar cells in the inert atmosphere indicates that both the short circuit current and energy conver- sion efficiency of the organic solar cells obviously decrease after photoaging. Incident photoelec- tric conversion efficiency （IPCE） tests show that the absorbing ability of the active layer obvious- ly reduces after photoaging. The morphologies characterized by scanning electron microscope （GEM） and atomic force microscopy （AFM） reveal the main cause of the performance reduction. The surface of the thin film ehanges significantly before and after photoaging, and the significant increase of the root mean square roughness is the main cause to make the device performance to become bad.