Direct Optical Observation of Stimulated Emission from Hot Charge Transfer Excitons in Bulk Heterojunction Polymer Solar Cells

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• 作者：Bhoj R. Gautam ; Andy Barrette ; Cong Mai ; Liang Yan ; Qianqian Zhang ; Evgeny Danilov ; Wei You ; Harald Ade ; Kenan Gundogdu
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 27, 2015
• 年：2015
• 卷：119
• 期：34
• 页码：19697-19702
• 全文大小：382K
• ISSN：1932-7455

文摘

Charge transfer excitons (CTEs) play an important role in semiconducting polymer-based optoelectronic applications. In organic photovoltaics, they are an intermediate step between tightly bound excitons and free charges. Although CT state energies at the interface of bulk heterojunction organic solar cells have been reported using quantum chemical calculations and by sensitive external quantum efficiency (EQE) measurements, direct optical observation of CT states was limited to relaxed, low energy, CT levels. Here we used polarization anisotropy transient absorption experiments to measure emission from high-energy CT levels. These experimental methods provide means to study high energy CT state dynamics in BHJs with controlled molecular orientations and complement theoretical calculations of interfacial CT state energies.