Evaluating effect of surface state density at the interfaces in degraded bulk heterojunction organic solar cell

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• 作者：Swati Arora^a ; ^{drswatia@yahoo.com} ; ; Vinamrita Singh^b ; Manoj Arora^c ; Ram Pal Tandon^b
• 关键词：Organic solar cell ; Degradation ; Lifetime ; Interface states ; Density of surface states
• 刊名：Physica B
• 出版年：2012
• 期刊代码：53_09214526
• 类别：ph
• 出版时间：1 August, 2012
• 卷：407
• 期：15
• 页码：3044-3046
• 文件大小：266 K

摘要

Degradation and short shelf life have been observed experimentally in poly(3-hexylthiophene) (P3HT): 6,6-phenyl C61-butyric acid methyl ester (PCBM) based blend solar cells. Both dark and illuminated current-voltage characteristics could be explained quantitatively with a proposed single model for a typical degraded organic solar cell-glass/ITO/PEDOT:PSS/P3HT:PCBM/Al. It has been found that surface state density, interface thickness, tunneling coefficient and occupation probabilities of the interface states becomes important with the passage of time. To look into the problem the activity at ITO/PEDOT:PSS and P3HT:PCBM/Al interfaces are studied using realistic values of the interfaces. The experimental J-V characteristics is well explained with the inclusion of tunneling current through these surface states and becomes the dominant current component for the degraded cell. It is also found that surface state density increases to 10¹²-10¹³ cm^鈭? eV^鈭?, which has been verified with C-V measurements and also is in agreement with our proposed model for BHJ solar cell after 150 h of fabrication.