Overcoming the trade-off between exciton dissociation and charge recombination in organic photovoltaic cells
Overcoming the trade-off between exciton dissociation and charge recombination in organic photovoltaic cells
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DOI：
10.1063/1.5045351
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发表时间：
2018-10
影响因子：
4
通讯作者：
Zhang Tao;R. Holmes
中科院分区：
文献类型：
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作者：
Zhang Tao;R. Holmes
电子给体-受体（D-A）界面是有机光伏电池（OPV）中实现有效激子解离和电荷产生的重要组成部分。然而，由于电子和空穴的紧密空间接近，它也可以实现快速电荷复合。为了阻止复合损失，已经尝试通过在D-A界面处引入绝缘阻挡夹层来分离电荷载流子。使用这种方法实现增加的效率是具有挑战性的，因为层间光学和传输能隙的相对相似性也可能阻碍激子收集和电荷产生。为了克服这种折衷，夹层必须阻挡电荷载流子，同时继续允许激子迁移到解离界面。在这项工作中，我们证明了这种配置在原型铜酞菁（CuPc）-C60平面OPV含有红荧烯夹层，以挫败电荷复合。关键的是，红荧烯和CuPc之间的三重态激子能级的相似性允许中间层对激子是可渗透的。含有中间层的器件显示出随着中间层厚度的增加，电荷转移态结合能和非成对复合率降低。对于薄夹层，孪晶复合也被抑制。因此，含有激子可渗透夹层的器件显示出开路电压、短路电流和功率效率的同时增加。电子给体-受体（D-A）界面是实现有机光伏电池（OPV）中激子有效解离和电荷产生的重要组成部分。然而，由于电子和空穴的紧密空间接近，它也可以实现快速电荷复合。为了阻止复合损失，已经尝试通过在D-A界面处引入绝缘阻挡夹层来分离电荷载流子。使用这种方法实现增加的效率是具有挑战性的，因为层间光学和传输能隙的相对相似性也可能阻碍激子收集和电荷产生。为了克服这种折衷，夹层必须阻挡电荷载流子，同时继续允许激子迁移到解离界面。在这项工作中，我们证明了这种配置在原型铜酞菁（CuPc）-C60平面OPV含有红荧烯夹层，以挫败电荷复合。关键是，三重态激子的相似性...
The electron donor-acceptor (D-A) interface is an essential component for realizing efficient exciton dissociation and charge generation in organic photovoltaic cells (OPVs). It can also however enable rapid charge recombination due to the close spatial proximity of electrons and holes. To frustrate recombination losses, attempts have been made to separate charge carriers by introducing an insulating blocking interlayer at the D-A interface. It is challenging to realize increased efficiency using this approach as the relative similarity of interlayer optical and transport energy gaps may also frustrate exciton harvesting and charge generation. To overcome this trade-off, the interlayer must block charge carriers while continuing to permit exciton migration to the dissociating interface. In this work, we demonstrate this configuration in archetypical copper phthalocyanine (CuPc)-C60 planar OPVs containing a rubrene interlayer to frustrate charge recombination. Critically, the similarity in triplet exciton energy levels between rubrene and CuPc allows the interlayer to be permeable to excitons. Devices containing an interlayer show a reduction in the charge transfer state binding energy and non-geminate recombination rate with increasing interlayer thickness. For thin interlayers, geminate recombination is also suppressed. Thus, devices containing an exciton permeable interlayer show a simultaneous increase in open-circuit voltage, short-circuit current, and power efficiency.The electron donor-acceptor (D-A) interface is an essential component for realizing efficient exciton dissociation and charge generation in organic photovoltaic cells (OPVs). It can also however enable rapid charge recombination due to the close spatial proximity of electrons and holes. To frustrate recombination losses, attempts have been made to separate charge carriers by introducing an insulating blocking interlayer at the D-A interface. It is challenging to realize increased efficiency using this approach as the relative similarity of interlayer optical and transport energy gaps may also frustrate exciton harvesting and charge generation. To overcome this trade-off, the interlayer must block charge carriers while continuing to permit exciton migration to the dissociating interface. In this work, we demonstrate this configuration in archetypical copper phthalocyanine (CuPc)-C60 planar OPVs containing a rubrene interlayer to frustrate charge recombination. Critically, the similarity in triplet exciton ...