Evaluating partner materials for the earth-abundant photovoltaic absorber ZnSnP2 for sustainable energy production

In this project we want to explore how the photovoltaic absorber material ZnSnP2 interacts with different potential partner materials for sustainable energy production. ZnSnP2 is composed of earth-abundant and recyclable elements with suitable optoelectronic properties for photovoltaic applications, however, it is missing suitable partner material to be grown as thin films. The understanding of how ZnSnP2 would interact with potential partner materials is necessary to determine the best processing route and potential recycling pathways.
The ZnSnP2 thin films will be grown using selective area epitaxy in nanoscale holes on different substrates. The nanoscale dimensions of the hole and the mask layer helps limit defect formation and propagation between layers, resulting in an improved materials quality. This opens up the use of a larger range of partner materials as compared to conventional thin-film deposition techniques. The exact interface structure can be determined using cross-sectional analysis through transmission electron microscopy of lamellae produced using focused ion beam processing. Moreover, the functional properties, such as bandgap, of ZnSnP2 are related to the order-disorder of the Zn and Sn atoms, where it has been demonstrated to be tuneable from 1.37 to 1.60 eV. To analyse local atomic positions and the bonding environment we want to employ x-ray absorption near edge spectroscopy at the ALBA Synchrotron.

本研究旨在探究光伏吸收材料二磷化锌锡（ZnSnP2）与不同潜在配伍材料的相互作用，以服务于可持续能源生产。二磷化锌锡由地壳储量丰富且可回收的元素构成，具备光伏应用所需的优良光电性能，但目前缺乏适配的配伍材料以制备其薄膜。明晰二磷化锌锡与潜在配伍材料的相互作用机制，是确定最优制备工艺路径与潜在回收方案的必要前提。
本研究将采用选择性区域外延技术，在不同衬底的纳米级孔洞中生长二磷化锌锡薄膜。孔洞与掩膜层的纳米尺度结构可有效限制层间缺陷的形成与扩展，从而提升材料质量。相较于传统薄膜沉积技术，该工艺可兼容的配伍材料范围更广。
可通过聚焦离子束制备薄片样品，再借助透射电子显微镜开展截面分析，以确定精确的界面结构。
此外，二磷化锌锡的带隙等功能特性与其锌、锡原子的有序-无序排布密切相关，已有研究证实其带隙可在1.37 eV至1.60 eV范围内调控。
为分析局部原子位置与键合环境，本研究计划在ALBA同步辐射光源（ALBA Synchrotron）采用X射线吸收近边光谱（X-ray absorption near edge spectroscopy）开展测试。