Critical Electron Transfer Rates for Exciton Dissociation Governed by Extent of Crystallinity in Small Molecule Organic Photovoltaics

详细信息    查看全文

• 作者：Susan Spencer ; Jeremy Cody ; Scott Misture ; Brandon Cona ; Patrick Heaphy ; Garry Rumbles ; John Andersen ; Christopher Collison
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 10, 2014
• 年：2014
• 卷：118
• 期：27
• 页码：14840-14847
• 全文大小：388K
• ISSN：1932-7455

文摘

Solution-processed bulk heterojunction organic solar cells fabricated with 1,3-bis[4-(N,N-diisopentylamino)-2,6-dihydroxyphenyl]squaraine and phenyl-C61-butyric acid methyl ester were found to exhibit unexpectedly low external quantum efficiency in the squaraine regions upon annealing. X-ray diffraction (XRD), spectral response, and time-resolved microwave absorption were all used to characterize the materials used and the devices prepared from them. An explanation for the drop in efficiency is proposed using Marcus鈥揌ush theory to tie together the changes in coherent crystal domain size found by XRD and the external quantum efficiency results. Exciton dissociation at the interface was determined to be the rate-limiting step in efficient current generation for these devices.