电荷转移配合物电子与光学性质研究及其在小分子太阳能电池中的应用

Organic photovoltaic devices (OPV) are of widespread interest due to their potential applications in low-cost renewable energy. While OPVs are entering a phase of rapid developments and challenges in recent years, its limited efficiency and stability is critical hurdle for practical usage. While the burgeoning interest has been put on developing high performance organic materials, our recent studies have shown that heavy doping/mixing of existing organic materials with strongly interacting inorganic materials (metals, metal oxides and halides) can form charge-transfer complex (CTC) materials with properties considerably differ from their constituents. Chemical/electronic interactions between the organic and the inorganic constituents can lead to formation of electronic gap states, substantial changes in charge donating/accepting abilities, thermal properties, and optical properties…etc. These new properties are important in enhancing the electrical conductivity, charge carrier dissociation/generation, optical absorption, morphological stability, etc., and applied in OPV devices. Albeit with these advances findings, there is only limited knowledge on the underlying principle behind such CTC containing materials. Systematic studies on their electronic structures (e.g. the density-of-states DOS distributions, work function, band gap, energy levels alignment, etc.) and their subsequent influence to optical and electrical properties are highly desirable. Herein, the investigator proposes to study the optical and electrical properties of two classes of these organic-inorganic composites: (I) organic:metal and; (II) organic:metal oxide or halide. Particular attention will be put on those composites formed between components with strong chemical/electrical interactions, which can potentially lead to novel properties that are not achievable via non-interactive mixing. Mechanisms and natures of the interactions would be studied with X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS) and knowledge so obtained would be used to explain and tailor the properties of composites. Selected composites with custom tuned electrical/optical properties would be applied in photovoltaic devices for performance and stability enhancement. The success of this project can shed light on the underlying physics behind the organic:inorganic composite materials and provide important guidance on tuning and tailoring of their properties. The ultimate target of the project is to demonstrate a simple and effective approach to manipulate the novel materials properties via the chemical/electronic coupling of the constituents. The findings of this research would be both scientifically and technically important for understanding and practical applications of organic:inorganic composite materials.

有机太阳能电池(OPV)在工业和科学上都有着重要的应用，并为解决我国能源短缺问题注入了希望，因此近年来对OPV的研究受到了广泛关注。然而效率低和稳定性差阻碍了OPV在实际中得以应用。目前大部分研究都以合成新材料为研究重点，因此我们创新性的提出将两种具有相互作用的有机与无机材料（如金属丶金属氧化物和金属卤化物）直接混合，通过给丶受体界面强烈的电荷转移作用形成与原材料性质完全不同的复合物材料。随着这种新型复合材料的出现，对其在电学光学及器件结构的研究中都出现了新的科学问题有待解决。因此，本项目旨在研究设计新型荷移复合材料，重点研究有机半导体与（I）金属；（II）金属氧化物或卤化物的电学(如态密度的分布、带隙、能带结构等)及光学性质。同时以以上结果为依据，选择合适的材料应用于新型红外光伏器件，以达到提升器件效率和稳定性。本项目的研究将为调控和应用新型荷移复合材料的性质提供理论和实验基础。

本项目旨在研究设计新型荷移复合材料，重点研究有机半导体与无机半导体的电学(如态密度的分布、带隙、能带结构等)及光学性质。采用不同技术和手段, 如X 射线光电子能谱(XPS)、和紫外光电子能谱(UPS)，表征荷移复合物材料的新电学和光学性能。同时以以上结果为依据，选择合适的材料应用于新型红外光伏器件，以达到提升器件效率和稳定性。..本项目的研究目标执行顺利并基本完成了计划书中的研究任务。1) 本小组通过组合不同有机-有机以及有机-无机半导体材料，采用简单的真空蒸镀技术，设计和制备多种不同的新型电荷转移复合物材料。2) 通过采用不同材料检测技术，如X射线光电子能谱(XPS)、和紫外光电子能谱(UPS)、椭圆偏振仪(Ellipsometer) 、吸收光谱等，对所制备的电荷转移复合物材料的电学和光学性能和界面结构等特征进行详细表征和分析。研究结果已在Adv. Mater上发表评论文章3) 制备了光响应从300 nm到1600 nm的宽光谱带响应的新型光敏器件。4) 应用有机：无机复合材料的优良性质以提高有机光电器件的效率，增强器件的稳定性。研究结果已在Adv. Mater.、Adv. Func.Mater.、Adv. Mater.Interface、ACS Appl. Mater. Interfaces和J. Mater. Chem. A等国际期刊上发表，　并有４篇文章被选为该期内封面。