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

PI: Hugh W hillhouse提案号：1133671知识产权太阳能是一种丰富而有前途的可再生能源，用于发电。然而，实现太阳能光伏发电（PV）以实现可持续能源的未来将需要低成本和地球丰富的光伏材料，以提供高太阳能转换效率。在这方面，铜-锌-锡-硫/硒化物（CZTSSe）正在成为PV材料的首选候选材料，但由于目前的PV层制造方法无法控制电子陷阱状态，因此太阳能转换效率较低。提出的研究将设计一种胶体纳米晶体-墨水路线，以产生具有低浓度电活性陷阱的致密CZTSSe层，从而产生具有低非辐射重组率的高质量光电薄膜，从而提供接近理论极限的潜在高效率。在纳米晶体-墨水制备CZTSSe层的方法中，胶体纳米晶体将被合成，然后悬浮在涂覆在基材上的墨水中。然后将纳米晶体层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、溶剂和不产生电活性陷阱的配体来控制CZTSSe纳米晶体生长的策略将通过一系列测量来确定，包括小角度x射线散射（SAXS）、成核和生长纳米晶体的原位紫外-可见-近红外光谱，以及纳米晶体和烧结膜的光致发光。此外，将开发一种独特的超声喷涂沉积策略，以形成具有明确定义的横向成分梯度的薄膜，因为吸收层成分的微小差异会对电子质量产生深远的影响。空间光伏特性将通过空间分辨光电流测量来筛选，以确定有利的缺陷化学成分，并且将从最有希望的成分中制造和测试可操作的太阳能电池。更广泛的影响除了培养研究生外，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指导当地小学生进行科学展览项目。PI将与西雅图的太平洋科学中心合作，进行清洁能源示范，通过科学咖啡馆项目进行演讲，并指导当地高中团队为太阳日准备项目，该太阳日将在西雅图举行，与IEEE光伏专家会议50周年纪念同时举行。

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.