Solar Cells from Silicon and Germanium Nanocrystals Inks

硅基太阳能电池是占主导地位的光伏技术，在2005年生产的所有电池中占有约90%的市场份额。然而，太阳能电池发电的成本仍然比化石燃料发电高出5-10倍。这个项目的目标是在使用硅（Si）和锗（Ge）纳米晶体油墨从溶液中制造太阳能电池的新范例的基础上，进行开发高效、低成本太阳能电池所需的基础研究。用已知的印刷技术如喷墨印刷对太阳能电池进行溶液处理被认为有可能将太阳能电池的制造成本降低十倍。此外，纳米晶体具有令人兴奋的特性，如可调节大小的吸收，以及在仅吸收单个光子的情况下有效地产生多个电子-空穴对的能力，这可能最终导致比由大块材料制成的设备更高效的太阳能电池。硅和锗纳米晶体的另一个优点是无毒、无环境危害、稳定性和丰度。几乎没有任何其他纳米晶体材料提供这种理想的属性范围。这项资助下的研究有四个重点：1)开发硅和锗纳米晶油墨导电薄膜的溶液组装路线；2)硅、锗纳米晶薄膜的电掺杂及其电学性能的研究；3)详细研究了Si和Ge纳米晶油墨及其溶液处理导电膜的基本光吸收特性；4)实际太阳能电池中硅和锗纳米晶薄膜的性能评价。这个项目的智力价值在于将通过提出的研究开发出从硅和锗纳米晶体形成导电薄膜的新方法。该项目还将阐明如何实现硅和锗纳米晶体薄膜的电掺杂，以及掺杂如何影响薄膜的电子和光学性质。最后，它将首次开发出完全由硅和/或锗纳米晶体油墨制成的太阳能电池。这个项目的广泛影响是重大的。这项被提议的研究可能最终使制造低成本纳米晶体太阳能电池的新方法成为可能，其效率可能超过那些大块材料电池。NSF-IGERT为“纳米粒子科学与工程”提供的杠杆将增加受该项目支持的研究生的教育机会。研究生和少数民族本科生的参与将促进研究和培训的整合，并促进代表性不足群体的参与。与明尼苏达科学博物馆的外展合作将向广大公众传播这项研究的结果。与工业伙伴的密切合作将确保知识迅速转移到工业。

CBET-0756326 KortshagenSilicon-based solar cells are the dominant photovoltaic technology with a market share of ~90% of all cells manufactured in 2005. However, the cost of electricity from solar cells is still by a factor of 5-10 higher than that of electricity from fossil fuels. The goal this project is to perform the basic research required to develop efficient, low-cost solar cells based on a new paradigm of manufacturing solar cells from solution using silicon (Si) and germanium (Ge) nanocrystal inks. Solution processing of solar cells by known printing techniques such as ink-jet printing is believed to have the potential to lower the solar cell manufacturing cost by up to a factor of ten. Moreover, nanocrystals have exciting properties such as size-tunable absorption and the ability to efficiently generate multiple electron-hole pairs on absorbing only a single photon, which may ultimately lead to more efficient solar cells than devices made from bulk material. Additional advantages of Si and Ge nanocrystals lie in their non-toxicity, lack of environmental hazard, stability, and abundance. Hardly any other nanocrystal material offers this range of desirable attributes.Research under this grant has four thrusts: 1) The development of routes for the solution-phase assembly of conductive films from Si and Ge nanocrystal inks; 2) the electrical doping of Si and Ge nanocrystal films and the study of their electrical properties; 3) the detailed investigation of the basic optical absorption properties of Si and Ge nanocrystal inks and of solution-processed conducting films thereof; and 4) the evaluation of the properties of Si and Ge nanocrystal films in actual solar cells. The intellectual merit of this project lies in new methods to form conductive films from Si and Ge nanocrystals that will be developed through the proposed research. This project will also elucidate how electrical doping of Si and Ge nanocrystal films can be achieved and how doping affects the electronic and optical properties of the films. Finally it will develop, for the first time, solar cells made exclusively from Si and/or Ge nanocrystal inks.The broader impacts of this project are significant. The proposed research may ultimately enable a new approach to the manufacture of low-cost nanocrystal solar cells, whose efficiencies may potentially exceed those of bulk material cells. Leverage provided by an NSF-IGERT for "Nanoparticle Science and Engineering" will enhance educational opportunities for graduate students supported by this project. The involvement of graduate students and minority undergraduate students will foster the integration of research and training, and the participation of underrepresented groups. Outreach collaboration with the Science Museum of Minnesota will communicate results of this research to a broad public. A close collaboration with an industrial partner will ensure rapid knowledge transfer to industry.