STTR Phase I: Perovskite Solar Cells with Tin Oxide Electron Transport Layers for Optimized Performance and Lifetime

这项小型企业技术转让（STTR）第一阶段项目的更广泛影响/商业潜力将体现在加强可再生能源格局，使我们的能源多样化，并最终减少化石燃料。随着我们的社会向能源供应和分配系统的清洁电气化迈进，美国对人类健康和环境的影响。由于其原材料成本低，固有的可扩展性和效率的快速发展，钙钛矿太阳能电池是验证薄膜光伏电池作为安全，商业上可行和经济上可持续的能源的理想候选者。这种迅速兴起的技术与现有的硅光伏电池兼容，可以与它们结合起来提高效率，或者可以作为独立的设备使用，最终达到或超过硅的性能，同时实现本质上廉价和可扩展的制造工艺。初步研究预测，在摊销初始资本投资后，组件的估计生产成本低于0.28美元/瓦，这意味着生产成本比目前的光伏技术低约30%。拟议的项目将为影响钙钛矿光伏电池寿命性能的关键降解机制提供解决方案。降解是由于在吸收光的钙钛矿层和电子传输层（通常是TiO2）之间的界面上捕获电荷，从而通过一系列化学反应导致钙钛矿结构的破坏。在这个项目中，二氧化钛将被SnO2（无论是固有的还是掺杂的）所取代，SnO2的电子能带结构与新的高效钙钛矿成分非常接近。此外，SnO2比TiO2便宜得多，更容易沉积，质量高，即电子缺陷密度低，并且在水分和氧气存在下比TiO2更环保。SnO2也不能光催化钙钛矿层的降解途径，最近认为这是发生在TiO2上的。使用SnO2作为电子传输层的初步实验室工作产生了与使用TiO2制造的电池相当的效率（~18%），但更重要的是，测试表明在运行500小时后几乎没有降解。我们的目标是进一步提高钙钛矿电池的性能（效率和稳定性），同时开发一种强大、廉价的SnO2沉积工艺。

The broader impact/commercial potential of this Small Business Technology Transfer (STTR) Phase I project will be seen in the strengthening of the renewable energy landscape, in the diversification of our energy sources, and ultimately in the reduction of fossil fuel?s impact on human health and the environment as our society moves toward clean electrification of our energy supply and distribution systems. Due to the low cost of its raw materials, intrinsic scalability and rapid evolution of efficiencies, perovskite solar cells are the ideal candidates to validate thin film photovoltaics as a safe, commercially viable and economically sustainable source of energy. This rapidly emerging technology is compatible with existing silicon photovoltaics and can be combined with them to enhance their efficiencies, or can be used as stand-alone devices that can ultimate meet or exceed the performance of silicon while enabling an intrinsically inexpensive and scalable manufacturing process. Initial studies predict an estimated cost of production of modules lower than $0.28/W after amortization of initial capital investment, which translates into a cost of production ~30% lower than that of current photovoltaic technologies.The proposed project will provide a solution to a key degradation mechanism that affects the lifetime performance of perovskite photovoltaics. Degradation is caused by trapping of charges at the interface between the light absorbing perovskite layer and the electron transport layer, typically TiO2, which leads to the breakdown of the perovskite structure through a sequence of chemical reactions. In this project TiO2 will be replaced by SnO2 (either intrinsic or doped) which has an electronic band structure that matches very closely with new high efficiency perovskite compositions. Additionally, SnO2 is considerable less expensive than TiO2, easier to deposit with high quality, i.e. low density of electronic defects, and it is more environmentally robust in the presence of moisture and oxygen than TiO2. SnO2 also does not photocatalyze degradation pathways of the perovskite layer, which is recently thought to be occurring with TiO2. Preliminary laboratory work using SnO2 as an electron transport layer yielded efficiencies comparable to cells manufactured using TiO2 (~18%), but more importantly, tests showed virtually no degradation after 500 hours of operation. Our goal is to further improve the properties of the perovskite cells (efficiency and stability) while developing a robust, inexpensive deposition process for SnO2.