Abstract Photoinduced charge generation forms the physical basis for energy conversion in organic photovoltaic (OPV) technology. The fundamental initial steps involved are absorption of light by organic semiconductors (generally π-conjugated polymers) to generate photoexcited states (Frenkel excitons) followed by charge transfer and charge separation processes in presence of suitable acceptor. The absorbed photon energy must be utilized completely for achieving maximum device efficiency. However progressive relaxation losses of instantaneously generated high-energy or hot-excited states form major bottleneck for maximum derivable voltage. This efficiency limiting factor has been challenged recently by the role of hot-carriers in efficient generation of charges. Therefore tailoring the dissociation of hot-exciton to be temporally faster than all relaxation processes could minimize the energy loss pathways. Implementation of this concept of hot-carrier photovoltaics demands critical understanding of molecular parameters that circumvent all energy relaxation processes and favor hot-carrier generation. In my dissertation work, I have examined the fate of photo-generated excitons in the context of polymer backbone and morphology, and therefore obtain a fundamental structure-function correlation in organic semiconductors.

中文翻译：

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有机半导体中激子的时间探测

摘要 光致电荷产生是有机光伏 (OPV) 技术中能量转换的物理基础。所涉及的基本初始步骤是有机半导体（通常是 π 共轭聚合物）吸收光以产生光激发态（弗伦克尔激子），然后在合适的受体存在下进行电荷转移和电荷分离过程。必须完全利用吸收的光子能量以实现最大的器件效率。然而，瞬时产生的高能或热激发态的渐进弛豫损失形成了最大可导出电压的主要瓶颈。这种效率限制因素最近受到热载流子在有效产生电荷中的作用的挑战。因此，将热激子的解离调整为比所有弛豫过程在时间上更快，可以最大限度地减少能量损失途径。热载流子光伏概念的实施需要对绕过所有能量弛豫过程并有利于热载流子生成的分子参数的批判性理解。在我的论文工作中，我在聚合物骨架和形态的背景下研究了光生激子的命运，因此获得了有机半导体中的基本结构 - 功能相关性。