COLLABORATIVE RESEARCH: Understanding and harnessing structural defects, doping, passivation, and alloying to increase Voc and efficiency of CdTe solar cells

标题：通过创新的工艺设计推进光伏技术非技术描述：该项目旨在发展材料科学和器件工程领域的新知识，以进一步提高基于镉镉的低成本光伏(PV)技术的性能。尽管光伏技术在过去20年中显示出巨大的市场增长和价格下降，但光伏发电仍不到我们总用电量的1%；通过提高设备性能来加速光伏的部署，可以进一步降低成本。该项目将研究几种工艺路线，以改善镉镉电池的输出电压，这是实现接近理想性能的剩余挑战。本研究力求将晶界等结构缺陷的负面影响降至最低，以改善控制镉镉电池输出电压的关键材料性能。重点将集中在研究元素杂质，特别是磷(P)掺杂，及其与晶界的相互作用和其他二维结构缺陷的镉镉薄膜及其合金。这两所学院的研究生将获得薄膜器件制造、晶体生长以及材料和器件表征的先进方法方面的经验。该项目还将影响K-12年级的学生，并提供薄膜太阳能电池的教育资源和光伏教育的材料。PI和副研究生将继续为初中生和高中生提供实践太阳能电池教学。技术描述：该项目的主要目标是创造基本知识和处理技术所需的提高镉镉光伏的输出电压。本研究有以下目标：(1)研究大尺寸材料中孤立晶界的影响，并利用所得结果调整多晶薄膜的性能；(2)研究V族掺杂(S)与沉积后处理技术联合使用对净p型掺杂的影响；(3)通过合金化Cd Te(Se，S)抑制结构缺陷，增强P型掺杂；(4)通过合金化降低关键器件界面的界面复合，如主结和背接触。上述目标将通过一个整体的方法来实现，该方法将包括研究大毫米颗粒尺寸的块体材料、器件质量的多晶薄膜和最先进的器件结构。该项目的实验部分将植根于基础材料研究，并扩展到设备工程。这些活动将使用设备物理模型来指导，以预测太阳能电池的性能。该项目的结果可能会对太阳能电池的制造产生直接影响，并可能在提高多晶镉镉太阳能电池的效率和降低成本方面带来范式转变的影响。

Title: Advancing photovoltaic technologies through innovative process designNon-Technical Description:This project aims at developing new knowledge in the areas of materials science and device engineering to further advance the performance of the low cost photovoltaic (PV) technology based on CdTe. Despite the tremendous market growth and price reduction demonstrated by PV technologies over the last two decades, PV-generated electricity remains below 1% of our total electricity usage; further cost reduction could be achieved through higher device performance leading to accelerated deployment of PV. The project will investigate several processing routes to improve the output voltage of the CdTe cell, which is the remaining challenge to achieving near ideal performance. This research seek to minimize the negative impact of grain boundaries and other structural defects, in order to improve key material properties which control the output voltage of CdTe cells. The focus will be on studying elemental impurities, specifically phosphorous (P) doping, and its interaction with grain boundaries and other 2D structural defects in CdTe films and their alloys. Graduate students at both institutions will gain experience in thin film device fabrication, crystal growth, and advanced methods of characterization of materials and devices. This project will also impact students from K-12 and provide educational resources on thin film solar cells and materials on PV education. The PIs and associate graduate students will continue hands-on solar cell teaching outreach to middle and high school students. Technical Description:The main goal of this project is to create the fundamental knowledge and processing techniques required to advance the output voltage of CdTe PV. This research has the following objectives:(1) investigate the effect of isolated grain boundaries in large mm grain size materials, and use the findings to tailor the properties of polycrystalline thin films; (2) investigate the combined effect of group V dopant(s) with post-deposition processing techniques on the net p-type doping; (3) enhance p-type doping by suppressing structural defects through alloying CdTe(Se,S); (4) lower interface recombination at critical device interfaces, such as the main junction and back contact, through alloying. The above goals will be pursued through a holistic approach that will include the investigation of large mm grain size bulk materials, device quality polycrystalline thin films, and state-of-the-art device structures. The experimental component of the project will be rooted in fundamental material studies and expanded to device engineering. The activities will be guided using device physics models to predict solar cell performance. Results from this project may have a direct impact on solar cell manufacturing and could lead to a paradigm shift impact in terms of improving efficiency and decreasing cost of polycrystalline CdTe-based solar cells.