Cu2Zn(Sn,Ge)S4 Nanocrystal-Ink Based Solar Cells: Colloidal Nanocrystal Growth and Control of Electrically Active Traps

PI：Hugh W Hillhouse建议编号：1133671智慧价值太阳能是一种储量丰富、前景广阔的可再生能源，可用于发电。然而，实现太阳能光伏(PV)以实现可持续能源的未来将需要低成本和富含地球的元素来提供高太阳能转换效率的光伏材料。在这方面，铜锌锡硫/硒化合物(CZTSSe)正在成为首选的光伏材料，但由于目前的光伏层制备方法无法控制电子陷阱状态，因此存在太阳能转换效率低的问题。这项拟议的研究将设计一种胶体纳米晶体-墨水路线，以产生致密的CZTSSe层和低浓度的电活性陷阱，从而产生具有低非辐射复合速率的高质量光电薄膜，提供潜在的高效率，接近理论极限。在制备CZTSSe层的纳米晶-墨水路线中，将合成胶体纳米晶，然后悬浮在涂覆在衬底上的墨水中。然后对纳米晶层进行烧结，以产生用于太阳能光伏电池的高质量致密多晶光吸收层。使用表面活性剂、溶剂和配体控制CZTSSe纳米晶生长的策略将通过一系列测量来确定，包括小角X射线散射(SAXS)、成核和生长纳米晶的原位UV-VIS-NIR光谱以及纳米晶和烧结膜的光致发光。此外，还将开发一种独特的超声喷射沉积策略，以形成具有明确横向组成梯度的薄膜，因为吸收层组成的微小差异可能会对电子质量产生深远影响。然后，空间光伏特性将通过空间分辨光电流测量进行筛选，以确定有利的缺陷化学成分，并将从最有希望的组合物中制造和测试运行中的太阳能电池。更广泛的影响除了培训研究生外，拟议的活动还将吸引公众和K-12学生参与太阳能主题。一名通过女性工程师协会工作的研究生将通过科学博览会项目指导当地小学生。PI将与西雅图的太平洋科学中心合作，创建清洁能源演示，通过Science Cafe计划进行演讲，并指导当地高中团队为太阳能日准备项目，该日正在西雅图举行，与IEEE光伏专家会议50周年同时举行。

PI: Hugh W HillhouseProposal Number: 1133671Intellectual MeritSolar energy is an abundant and promising renewable energy resource for the generation electricity. However, the realization of solar photovoltaics (PV) for achieving a sustainable energy future will require low-cost and earth-abundant elements for PV materials which offer high solar energy conversion efficiency. In this regard, Copper-Zinc-Tin-Sulfur/Selenide (CZTSSe) is emerging as top candidate PV material, but suffers from low solar energy conversion efficiency because the electronic trap states cannot be controlled through current PV layer fabrication approaches. The proposed research will engineer a colloidal nanocrystal-ink route to yield dense CZTSSe layers with low concentrations of electrically-active traps to yield high quality optoelectronic films with low rates of non-radiative recombination that offer potentially high efficiencies which approach theoretical limits. In the nanocrystal-ink route for fabrication of CZTSSe layers, colloidal nanocrystals will be synthesized and then suspended in an ink that is coated on substrate. The nanocrystal layer is then sintered to yield a high quality dense polycrystalline photoabsorbing layer for the solar PV cell. Strategies to control CZTSSe nanocrystal growth with surfactants, solvents, and ligands that do not yield electrically active traps will be identified through a suite of measurements, including small-angle x-ray scattering (SAXS), in-situ UV-Vis-NIR spectroscopy of the nucleating and growing nanocrystals, and photoluminescence of the nanocrystals and sintered films. Furthermore, a unique ultrasonic spray deposition strategy will be developed to form films with a well defined lateral composition gradient, as small differences in the absorber layer composition can have a profound effect on the electronic quality. The spatial photovoltaic properties will then be screened with spatially resolved photocurrent measurements to identify favorable defect chemistries, and operating solar cells will be fabricated and tested from the most promising compositions. Broader ImpactsIn addition to training graduate students, the proposed activities will engage the public and K-12 students in solar energy topics. A graduate student working through the Society of Women Engineers will mentor local elementary school students with science fair projects. The PI work will with the Pacific Science Center in Seattle to create clean energy demonstrations, make presentations through the Science Cafe program, and mentor local high school teams to prepare projects for Solar Day, which is being held in Seattle in conjunction with the 50th Anniversary of the IEEE Photovoltaics Specialists Conference.