Additive Manufacturing of Conformal Solar Cells via Xenon-Light-Assisted Sintering

符合三维物体形状的太阳能电池是一种理想的可再生能源，用于自我维持设备（例如，建筑物中的智能窗户，以及用于监测汽车和飞机结构完整性的传感器）。制造保形太阳能电池的传统路线是将其功能层制作在柔性中间聚合物片上，并将其附着在所需的三维物体上。在附着过程中，薄片会变形，使其符合物体的三维形状。薄片的这种变形经常导致细胞功能层的破裂和细胞功能的丧失。该奖项支持对一种新的增材制造工艺的科学研究，该工艺可以在三维物体上制造保形太阳能电池，而不使用任何中间聚合物片。这项研究的结果将使太阳能电池作为一种可再生能源更广泛地应用于能源、通信、航空航天和汽车工业的自我维持设备。该项目旨在通过将喷墨沉积和氙光辅助纳米颗粒烧结相结合，开发新的共形太阳能电池增材制造工艺。研究目的是了解纳米颗粒特性（尺寸和化学计量）与烧结材料特性（密度和化学成分）之间关系的物理化学机制（即光诱导纳米颗粒加热、温度升高诱导纳米颗粒之间的质量传递以及质量传递诱导的化学反应）之间的相互作用。通过耦合纳米粒子的光学加热（通过电磁有限元分析）、纳米尺度的传质和反应动力学（使用分析模型）以及温度和应力的中尺度演化（通过烧结的中尺度有限元分析），将开发一个基于物理的模型。某些模型参数（例如，纳米颗粒尺寸分布和熔点）将通过使用量热法、分光光度法和光谱学测量纳米颗粒特性来校准。为了验证模型，将使用新工艺烧结具有不同特性的纳米颗粒，并将烧结材料的特性（使用电子显微镜、x射线衍射和红外成像测量）与模型预测进行比较。该验证模型将用于预测纳米颗粒特性对烧结材料性能的影响，以及过程中物理化学机制的关键指标（例如，沉积纳米颗粒的温升速率，沉积纳米颗粒的收缩和应力，以及沉积纳米颗粒中未反应材料与相变材料的比例）。

Solar cells that conform to the shape of a three-dimensional object are desirable as a renewable energy source for self-sustaining devices (e.g., smart windows in buildings, and sensors for monitoring structural integrity in automobiles and airplanes). The conventional route for manufacturing conformal solar cells is to fabricate their functional layers onto a flexible intermediary polymer sheet, and attach the sheet onto the desired three-dimensional object. During attachment, the sheet is deformed so that it conforms to the object's three-dimensional shape. This deformation of the sheet frequently causes cracking of the cell's functional layers and a loss in the cell's functionality. This award supports scientific investigations on a new additive manufacturing process for fabricating conformal solar cells onto a three-dimensional object, without using any intermediary polymer sheet. Results from this research will enable wider use of solar cells as a renewable energy source for self-sustaining devices in energy, communications, aerospace, and automotive industries.This project aims to develop the new additive manufacturing process for conformal solar cells by integrating inkjet deposition and xenon-light-assisted nanoparticle sintering. The research objective is to understand the interaction between physio-chemical mechanisms (i.e., optically induced nanoparticle heating, temperature rise induced mass transport between nanoparticles, and mass transport induced chemical reactions) that underlie the relationship between nanoparticle characteristics (size and stoichiometry) and sintered material properties (density and chemical composition). A physics-based model will be developed by coupling optical heating of nanoparticles (via electromagnetic Finite Element Analysis), nanoscale mass transfer and reaction kinetics (using analytical models), and mesoscale evolution of temperature and stress (via mesoscale Finite Element Analysis of sintering). Certain model parameters (e.g., nanoparticle size distribution and melting points) will be calibrated by measuring nanoparticle characteristics using calorimetry, spectrophotometry, and spectroscopy. To validate the model, nanoparticles with varying characteristics will be sintered using the new process, and sintered material properties (measured using electron microscopy, X-ray diffraction, and infrared imaging) will be compared to model predictions. This validated model will be used to predict the effects of nanoparticle characteristics on sintered material properties, and on key indicators of physio-chemical mechanisms during the process (e.g., rate of temperature rise of deposited nanoparticles, shrinkage and stresses in deposited nanoparticles, and ratio of unreacted material to material with changed phase in deposited nanoparticles).