Optical, Electrical and Magnetic Studies of pi-Conjugated Polymer/Organic Acceptor Blends for Photovoltaic Applications

用于光伏应用的 π 共轭聚合物/有机受体混合物的光学、电学和磁学研究

• 批准号: 0803325
• 负责人: Zeev Valy Vardeny
• 金额: --
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-15 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0803325&HistoricalAwards=false
• 关键词: Optical; Electrical; Magnetic; Studies; pi

Technical: This project aims for greater understanding of electronic states, charge transport, and spin phenomena in blends of PCP (p-conjugated polymers) with molecular acceptors that are used in bulk-heterojunction OPV (organic photovoltaic) devices. Processes/phenomena to be investigated in blends (films and devices) include: ultrafast exciton dissociation, charge generation mechanism, below-gap response, formation of charge transfer complex (CTC) of PCP chains and acceptor molecules, geminate recombination, spin-dependent transport and recombination, and morphology-dependent carrier mobility. These studies will be conducted in PCP-fullerene blends of different concentrations that show high OPV efficiency, as well as in novel PCP-acceptor blends that have not been used before. Outcomes are expected to contribute to basic understanding of physical processes that govern photovoltaic response in OPV devices, and have potential to increase their solar power conversion efficiency beyond the 6% record of the present time. The approach utilizes optical, electrical and magnetic experimental techniques: (i) ultrafast exciton and polaron dynamics in the blends will be investigated using a pump/probe photomodulation (PM) technique in the spectral range of 0.1 to 2.5 eV; (ii) the excitation in (i) is to vary from above to below-gap photon energy to explore the possibility of polaron generation by processes other than traditional charge transfer from the polymer chain onto the acceptor molecule; (iii) the possible formation of a CTC state in the blends will be studied by IR-photoluminescence, below-gap absorption, IR-electroabsorption, and photogenerated polaron action spectra; (iv) electrical admittance spectroscopy for obtaining the carrier mobilities; (v) magnetoresistance measurements of OPV devices for studying polaron recombination; and (vi) dynamics of optically-detected magnetic-resonance of spin ½ polarons for studying spin-dependent recombination, and spin-lattice relaxation rate in OPV devices. Non-technical: The project addresses basic research issues in a topical area of electronic/photonic materials science with high technological relevance. These studies may lead to OPV (organic photovoltaic) devices with enhanced solar power conversion efficiency, and deepen our understanding of the PCP-acceptor blends. In addition, the integration of experimental efforts, including polymer and small molecule synthesis, optics, magneto-transport, modeling, and device fabrication, processing and testing, will serve to educate graduate and undergraduate students, and a postdoctoral associate who will be involved in this interdisciplinary research project. A graduate course on ?Organic optoelectronics; basic studies and device applications? is also planned. An outreach program includes research participation of high school students and their teacher mentors during the summer, as well as engineering demonstrations for illustrating organic light emitting diodes and OPV devices to the public.

技术：该项目旨在更好地了解PCP(p-共轭聚合物)与用于体-异质结OPV(有机光伏)器件的分子受体共混物中的电子态、电荷传输和自旋现象。共混物(薄膜和器件)中需要研究的过程/现象包括：超快激子解离、电荷产生机制、带隙以下响应、PCP链和受体分子的电荷转移络合物(CTC)的形成、双态复合、自旋相关的输运和复合以及形态相关的载流子迁移率。这些研究将在显示出高OPV效率的不同浓度的PCP-富勒烯混合物中进行，以及在以前从未使用过的新型PCP-受体混合物中进行。预计结果将有助于基本了解控制OPV设备中光伏响应的物理过程，并有可能将其太阳能转换效率提高到超过目前6%的纪录。该方法利用光学、电学和磁学实验技术：(I)将利用泵浦/探测光调制(PM)技术在0.1-2.5 eV的光谱范围内研究共混物中超快激子和极化子的动力学；(Ii)在(I)中的激发将从高于能隙的光子能量变化到低于能隙的光子能量，以探索除了传统的从聚合物链到受体分子的电荷转移之外的过程产生极化子的可能性；(Iii)将通过红外光致发光、能隙以下吸收、红外电吸收和光产生极化子作用光谱来研究共混物中CTC态的可能形成；(Iv)用于获得载流子迁移率的电导纳谱；(V)用于研究极化子复合的OPV器件的磁阻测量；以及(Vi)用于研究与自旋相关的复合的自旋1/2极化子的光学检测磁共振的动力学，以及OPV器件中的自旋-晶格弛豫速率。非技术性：该项目涉及具有高度技术相关性的电子/光子材料科学专题领域的基础研究问题。这些研究可能导致OPV(有机光伏)器件具有更高的太阳能转换效率，并加深我们对PCP-受体共混物的理解。此外，整合实验工作，包括聚合物和小分子合成、光学、磁传输、建模和设备制造、加工和测试，将有助于培养研究生和本科生，以及将参与这一跨学科研究项目的博士后助理。有机光电子学、基础研究和器件应用的研究生课程？也在计划之中。外展计划包括高中生和他们的教师导师在暑期参与研究，以及向公众展示有机发光二极管和OPV设备的工程演示。