Probing Enhanced Exciton Diffusion in a Triplet-Sensitized Organic Photovoltaic Cell
Probing Enhanced Exciton Diffusion in a Triplet-Sensitized Organic Photovoltaic Cell
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DOI：
10.1021/acs.jpcc.9b11091
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
Kaicheng Shi;Ian J. Curtin;Andrew T. Healy;Tao Zhang;Deepesh Rai;D. Blank;R. Holmes
中科院分区：
文献类型：
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作者：
Kaicheng Shi;Ian J. Curtin;Andrew T. Healy;Tao Zhang;Deepesh Rai;D. Blank;R. Holmes
我们研究激子扩散的三重态敏化的有机光伏电池，通过长寿命的荧光电子供体的三重态发生运输。虽然三重态在光学上是暗的，但它是通过能够进行系统间穿越的客体物种的敏化来填充的。这里，主体材料是无金属酞菁（H2Pc），三线态敏化客体是铜酞菁（CuPc）。H2 Pc的光激发导致单重态激子的产生，这些激子迅速进行能量转移到CuPc。CuPc上的激子经历系统间穿越到三重态，然后能量转移回到H2Pc三重态。激子扩散长度（LD）提取使用内部量子效率比的方法，允许精确的基于设备的测量激子传输，即使在存在的双生复合损失。施主层LD随组分的变化而变化，在20vol%的CuPc处观察到最大LD为（13.4 ± 1.6 nm），在20vol%的CuPc处观察到最大LD为（13.4 ± 1.6 nm）。
We examine exciton diffusion in a triplet-sensitized organic photovoltaic cell, where transport occurs via the long-lived triplet state of a fluorescent electron donor. While the triplet state is optically dark, it is populated via sensitization by a guest species capable of intersystem crossing. Here, the host material is metal-free phthalocyanine (H2Pc), and the triplet-sensitizing guest is copper phthalocyanine (CuPc). Optical excitation of H2Pc leads to the generation of singlet excitons which rapidly undergo energy transfer to CuPc. Excitons on CuPc undergo intersystem crossing to the triplet state followed by energy transfer back to the H2Pc triplet state. The exciton diffusion length (LD) is extracted using an internal quantum efficiency ratio methodology that permits accurate device-based measurements of exciton transport even in the presence of geminate recombination losses. The donor layer LD varies with composition with a maximum LD of (13.4 ± 1.6 nm) observed at 20 vol % CuPc, an almost 60% in...