中国科学院力学研究所机构知识库

激光诱导前向转移技术（Laser Induced Forward Transfer，简称 LIFT）是一种高效的数字化定向转移技术，具有非接触、无损伤，材料适用性好的特点，使得它在多种相态材料的精确转移中展现出巨大的应用潜力。针对不同种类的被转移材料，LIFT 技术能够灵活调整其转移模式，以实现最佳转移效果。本文重点关注以银浆为代表的非牛顿体浆料作为被转移材料的研究，系统研究了激光诱导下银浆的转移工艺过程，获得了不同工艺参数对转移结果的影响规律，并探索和分析了银浆的非牛顿流体特性对激光诱导转移机制的影响。提出了太阳能电池电极栅线的形貌表征方法，在此基础上建立了激光-受力-成形形貌的关系，并对银浆转移过程进行了分类；通过一系列实验设计和详尽的数据分析，对激光诱导成形过程有了更加深入的认识，获得了窄线宽、大高宽比、均匀连续的栅线。

实验平台采用自主研发的 LIFT 成形系统，该系统集成了激光器、光束传输系统、工作台和控制系统等多个核心组件，为实验提供了稳定且高效的激光加工环境。此外，刮浆系统、观测系统和烘干烧结系统也是本文技术实现不可或缺的组成部分。这些系统协同工作，构成了本文所研究激光诱导银浆成形技术的设备基础。

通过实验设计，改变激光能量密度等重要参数，旨在深入研究通过激光诱导前向转移（LIFT）技术沉积的栅线的多样化形态。借助激光共焦成像技术，描述了栅线的多种形态，并据此提出了针对太阳能电池栅线的多种形态表征方案。通过对比分析实验数据，探究了不同类型的栅线形态与实验参数之间的内在联系，进而归纳出了无转移、线转移和散斑转移这三种典型的转移形式，理解 LIFT 技术的多种转移机制提供了参照。

将栅线的成形过程分为发泡、接触和分离三个阶段。这三个阶段中，银浆的行为特征因转移形式的不同而呈现出显著差异。在无转移形式下，银浆在发泡阶段未能有效形成稳定的凸起，导致后续无法形成接触，没有连续的栅线产生。而在线转移形式中，银浆在发泡阶段形成稳定的凸起，随后在接触阶段与基底材料良好浸润，最终在分离阶段形成连续的栅线。散斑转移形式的银浆在发泡阶段的高压作用下不稳定，导致破裂，栅线形态表现为不连续的散斑状。结合银浆的流变特性和与材料的浸润性，分析了激光诱导银浆的转移机制，深入理解栅线成形过程、优化工艺参数以及进一步提升栅线成形质量奠定了坚实的基础。

Laser Induced Forward Transfer (LIFT) is an efficient digital directional transfer technology. It has the characteristics of non-contact, non-damage and good material applicability, which makes it show great potential in accurate transfer of various phase materials. For different types of transferred materials, LIFT technology can flexibly adjust its transfer mode to achieve the best transfer effect. In this paper, we focus on the study of silver paste as non-Newtonian material, systematically study the transfer process of silver paste induced by laser, obtain the influence of different process parameters on the transfer results, and explore and analyze the influence of non-Newtonian fluid characteristics of silver paste on the mechanism of laser induced transfer. A method for characterizing the morphology of solar cell grid lines was proposed. Based on this, the relationship between laser-force-forming morphology was established, and the silver paste transfer process was classified. Through a series of experimental designs and detailed data analysis, the laser-induced forming process was more deeply understood, and narrow linewidth, large aspect ratio and uniform continuous grid lines were obtained.

The experimental platform adopts the self-developed LIFT forming system, which integrates multiple core components such as laser, beam transmission system, workbench and control system, providing a stable and efficient laser processing environment for the experiment. In addition, scraping system, observation system and drying and sintering system are also indispensable parts of this paper. These systems work together and constitute the equipment foundation of laser induced silver paste forming technology studied in this paper.

By changing the laser energy density and other important parameters, the experiment design aims to study the diversified morphology of the grating deposited by laser induced forward transfer (LIFT) technology. With the help of laser confocal imaging technology, various shapes of grid lines are described, and based on this, various shape characterization schemes for solar cell grid lines are proposed. By comparing and analyzing the experimental data, the intrinsic relationship between different types of grating line shapes and experimental parameters is explored, and then three typical transfer forms, namely, no transfer, line transfer and speckle transfer,  are summarized, which provides a reference for understanding various transfer mechanisms of LIFT technology.

The forming process of grid line can be divided into three stages: foaming, contact and separation. In these three stages, the behavior characteristics of silver paste showed significant differences due to different transfer forms. In the non-transfer form, the silver paste failed to form stable bumps in the foaming stage, resulting in no contact formation and no continuous grid lines. In the form of line transfer, the silver paste forms stable bumps in the foaming stage, then wets well with the substrate material in the contact stage, and finally forms continuous grid lines in the separation stage. The silver paste in speckle transfer form is unstable under high pressure in foaming stage, resulting in fracture, and the grid line morphology is discontinuous speckle shape. Combined with rheological properties and wettability of silver paste, the mechanism of laser-induced silver paste transfer is analyzed, which lays a solid foundation for further understanding the forming process of grid lines,optimizing process parameters and improving the forming quality of grid lines.