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

由于太阳能取之不尽用之不竭，通过光伏发电（PV）将太阳光转化为电能是一种有前途的长期可持续能源技术。在这个NSF-两国科学基金会（BSF）项目中，德雷克塞尔大学将与以色列的Bar-Ilan大学合作，对新材料设计和合成策略进行基础研究，以生产用于高效太阳能转换的光学透明半导体。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来获得。 将使用这些材料制备和评估设备，这些材料将同时有效地吸收紫外线和红外线太阳光，但透射可见光，并将吸收的光有效地转化为电能。新的太阳能吸收器范例依赖于廉价、地球资源丰富、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改变光伏太阳能转换能力。在这个项目中进行的调查将推进光电流产生机制的基础知识，有望大大提高基于铁电氧化物的光伏电池的太阳能转换效率。该项目也是一个理想的培训骨干人才的年轻工程师，包括那些从历史上代表性不足的群体，以解决重要的基础材料工程的挑战，并参与推广活动的一部分，合作，跨学科的努力。新颖，高效的太阳能热载流子转换机制是有希望的铁电氧化物薄膜中使用的单吸收，透明的光致发光。该项目将导致加工和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的基础知识。该项目的方法使用了一系列紧密耦合的实验和理论研究。该研究计划将先进材料加工和器件制造与基础材料设计和理解相结合，以实现红外和紫外光吸收，可见光透明度和功能铁电特性的不寻常组合，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。沉积和沉积后的处理协议，使使用的半导体铁电型薄膜的透明光伏吸收器将进行研究，沿着设备的制造，测试和分析。虽然计算方法已被用于材料发现，但它们用于阳离子掺杂和富氧空位的半导体铁电氧化物钙钛矿固溶体加工的基础研究将是理论指导加工研究的首批例子之一。基于PI和他的以色列合作者之间的合作，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，并将提高基于第一原理密度泛函理论的计算方法的准确性。

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.