Collaborative Research: Leveraging a Solvent Toolkit for Doping and Characterizing Hybrid Perovskite Solar Cells

非技术：太阳能电池有助于开发环境友好型能源。基于混合有机/无机材料的太阳能电池已经达到了与商用设备相当的性能水平。低成本加工和灵活性等特性使其成为硅的有吸引力的替代品。然而，混合太阳能电池性能的提高受到当前制造和表征策略的限制。pi已经表明，这些材料可以通过液体进行电化学掺杂而不溶解它们。这种液体方法产生了一个工具包，可用于测量和增强内在电性能。这种液体工具箱将用于改进和增强混合太阳能电池。pi将通过计算机建模确定混合太阳能电池的有前途的材料组合。薄膜将制备、表征和优化用于太阳能电池。混合太阳能电池将制造和表征太阳能转换和稳定性。进一步的研究将查明退化的原因。这些努力将进一步发挥混合太阳能电池的潜力，改变太阳能的格局。拟议的努力将包括教育和外展活动，以扩大代表性不足的群体的参与，吸引公众参与，并培训下一代可再生能源方面的科学家和工程师。德克萨斯州立大学是一所西班牙裔服务机构。拟议的项目将利用这一人才库来增加研究和STEM教育的多样性。技术方面：pi将使用最近开发的溶剂工具包对混合钙钛矿（HP）薄膜和太阳能电池设备进行电涂和表征。该溶剂工具包基于氢氟醚（HFE）溶剂体系，对HP无破坏性，并允许对HP薄膜进行电化学表征和改性。为了生产具有良好电学和光学性能的p和n掺杂器件，项目团队将利用三种方法从溶剂工具箱技术提供的广泛可能的器件中确定最佳器件组成。为了描述广阔的潜在实验前景，将使用密度泛函理论（DFT）进行数值模拟，以确定有利的掺杂混合物。随后，将对HFE电解质中的HP薄膜进行电化学研究，实验实现提高电导率和新能级等掺杂效果。最后，在电化学研究的驱动下，将采用掺杂策略制备HP太阳能电池，并对其效率、结构和稳定性进行仔细的表征。更具体地说，我们将利用带有Hubbard校正和自旋-轨道耦合的DFT来研究不同离子掺杂对HP材料的能带结构、带隙、掺杂能级、反演对称性损失、Rashba效应、自旋织构、电子-声子耦合和量子约束的影响。电化学（EC）掺杂将通过计时电位法和计时电流法在HFE溶剂中完成，并通过循环伏安法、方波伏安法和定制多路复用芯片的电化学阻抗谱进行表征。HP太阳能电池装置将由HFE加工掺杂的薄膜制成，并测试其效率和寿命指标。随后，我们将研究当器件受到光和温度循环的压力时，EC掺杂HP薄膜如何影响器件的性能和稳定性。我们将把HP-PV器件参数（功率转换效率、短路电流、开路电压、填充因子、滞后等）的变化与器件在无空气环境中进行可控老化时的结构、化学和光学特性联系起来。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical:Solar cells are instrumental to efforts to develop environmentally friendly power sources. Solar cells based on hybrid organic/inorganic materials have achieved performance levels comparable to commercial devices. Properties such as low-cost processing and flexibility make them an attractive alternative to silicon. However, improving the performance of hybrid solar cells has been limited by current fabrication and characterization strategies. The PIs have shown that these materials can be electrochemically doped by a liquid without dissolving them. This liquid approach yields a toolkit that can be used to measure and enhance intrinsic electrical properties. This liquid toolkit will be used to modify and enhance hybrid solar cells. The PIs will identify promising materials combinations for hybrid solar cells by computer modeling. Thin films will be prepared, characterized, and optimized for solar cells. Hybrid solar cells will be fabricated and characterized for solar power conversion and stability. Additional studies will identify causes of degradation. These efforts will further the potential of hybrid solar cells to transform the solar energy landscape. The proposed effort will involve education and outreach activities to broaden participation of underrepresented groups, engage the public, and train the next generation of scientists and engineers in renewable energy. Texas State University is a Hispanic Serving Institution. The proposed project will leverage this talent pool to increase diversity in research and STEM education.Technical:The PIs will electrically dope and characterize hybrid perovskite (HP) thin films and solar cell devices using a recently-developed solvent toolkit. This solvent toolkit is based on a hydrofluoroether (HFE) solvent system that is nondestructive to HPs and permits electrochemical characterization and modification of HP thin films. To produce p and n doped devices of favorable electrical and optical performance, the project team will utilize three approaches to identify optimal device compositions from the wide range of possible devices afforded by the solvent toolkit technique. To characterize the broad potential experimental landscape, numerical modeling with density functional theory (DFT) will be performed, identifying favorable doping mixtures. Subsequently, electrochemical study of thin HP films in HFE electrolytes will be performed to experimentally achieve doping effects such as improved conductivity and new energy levels. Finally, HP solar cells will be fabricated from doping strategies motivated by electrochemical study, and carefully characterized for efficiency, structure and stability. More specifically, we will utilize DFT with Hubbard correction and spin-orbital coupling to investigate the effects of different ionic dopants on the band structure, bandgap, doping energy levels, loss of inversion symmetry, Rashba effect, spin texture, electron-phonon coupling, and quantum confinement of HP materials. Electrochemical (EC) doping will be accomplished in HFE solvents with chronopotentiometry and chronoamperometry and characterized with cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy with custom multiplexed chips. HP solar cell devices will be fabricated from films doped by HFE processing and tested for efficiency and lifetime metrics. We will subsequently investigate how the EC doping of HP films affects device performance and stability while the device is being stressed with light and temperature cycles. We will correlate changes in HP-PV device parameters (power conversion efficiency, short-circuit current, open-circuit voltage, filling factor, hysteresis, etc.) with structural, chemical, and optical properties as the device undergoes controlled aging in the air-free atmosphere.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.