NSF/CBET-BSF: Processing of Polar Absorbers to Enable Hot-Carrier All-Oxide Transparent Solar Cells

太阳能是一种取之不尽、用之不竭的能源，利用光伏将太阳光转化为电能是一种很有前途的长期可持续能源技术。在这项NSF-BinNational Science Foundation(BSF)项目中，德雷克塞尔大学将与以色列的巴伊兰大学合作，就生产高效太阳能转换的光学透明半导体的新材料设计和合成策略进行基础研究。新材料将通过材料的计算设计和先进的合成、加工和性能测量相结合而获得。将使用这些材料来制备和评估设备，这些材料将同时有效地吸收紫外线和红外线阳光，但传输可见光，并将吸收的光高效地转化为电能。新的太阳能吸收器范例依赖于廉价、富含土地、无毒和稳定的材料，有可能利用现有的建筑窗户和其他建筑表面来改变光伏太阳能的转换能力。该项目开展的研究将促进对光电流产生机制的基础知识，有望显著提高基于铁电氧化物的光伏电池的太阳能转换效率。该项目也是对一批有才华的年轻工程师的理想培训，包括那些来自历史上代表性不足的群体，以应对重要的基础材料工程挑战，并参与外联活动，作为协作、跨学科努力的一部分。新颖、高效的太阳能转换热载流子机制有望在单吸收、透明光伏中使用铁电氧化物薄膜。该项目将使人们对透明光伏吸收膜的结构、光学和光生电荷传输特性和性能之间的关系有基本的了解。该项目的方法采用了一系列紧密耦合的实验和理论研究。这项研究计划将先进材料加工和器件制造方面与基础材料设计和理解相结合，以实现红外和紫外光吸收、可见光透明和功能铁电特性的非凡组合，从而使新型透明热载流子太阳能电池的效率可能超过Shockley-Queisser极限。将研究用于透明光伏吸收器的半导体铁电型薄膜的沉积和沉积后处理协议，以及器件制造、测试和分析。虽然计算方法已经被用于材料发现，但它们在阳离子掺杂和富氧缺位固溶体半导体铁电氧化物钙钛矿加工的基础研究中的应用将是理论指导的加工研究的第一个例子之一。在PI和他的以色列合作者合作的基础上，理论和实验的比较将为基于物理气相沉积的薄膜合成工作提供反馈，并将提高基于第一性原理密度泛函理论的计算方法的精度。

Due to an inexhaustible supply of energy from the sun, conversion of sunlight into electricity by photovoltaics (PVs) is a promising long-term sustainable energy technology. In this NSF-Binational Science Foundation (BSF) project, Drexel University, in partnership with Bar-Ilan University in Israel, will conduct a fundamental research study on new materials design and synthesis strategy for producing optically-transparent semiconductors for efficient solar energy conversion. The new materials will be obtained through a combination of computational design of materials and advanced synthesis, processing, and property measurements. Devices will be prepared and evaluated using these materials, which will simultaneously and efficiently absorb ultraviolet and infrared sunlight, but transmit visible light, and convert the absorbed light efficiently into power. The new solar energy absorber paradigm, which relies on inexpensive, earth-abundant, non-toxic and stable materials, has the potential to transform PV solar power conversion capacity using already existing building windows and other building surfaces. The investigations undertaken in this project will advance fundamental knowledge on the photocurrent generation mechanism that promises to dramatically enhance solar power conversion efficiencies of photovoltaic cells based on ferroelectric oxides. This project also serves as ideal training for a cadre of talented young engineers, including those from historically underrepresented groups, to tackle important fundamental materials engineering challenges and participate in outreach activities as part of collaborative, interdisciplinary effort.The novel, highly-efficient hot-carrier mechanism of solar energy conversion is promising for the use of ferroelectric oxide films in single absorber, transparent photovoltaics. This project will result in fundamental knowledge of the relationships between processing and the structural, optical and photo-generated charge transport properties and performance of transparent photovoltaic absorber films. The approach of the project uses a series of tightly coupled experimental and theoretical investigations. This research program combines aspects of advanced materials processing and device fabrication with fundamental materials design and understanding to achieve the unusual combination of infrared and ultraviolet light absorption, visible light transparency and functional ferroelectric properties for enabling novel transparent hot-carrier solar cells with efficiencies possibly beyond the Shockley-Queisser limit. Deposition and post-deposition processing protocols that enable the use of the semiconducting ferroelectric-type films for transparent photovoltaic absorbers will be researched, along with device fabrication, testing and analysis. While computational methods have been used for materials discovery, their use for fundamental studies of processing of cation-doped and oxygen vacancy-rich solid-solution semiconducting ferroelectric oxide perovskites will be one of the first examples for theory-guided processing research. Building on the collaborations between the PI and his Israel-based collaborator, comparison of theory and experiment will provide feedback for the physical vapor deposition-based film synthesis effort and will enhance the accuracy of the first principles density functional theoretical-based computational approach.