蒸发全钙钛矿串联太阳能电池中发散的固态转化路径
Divergent Solid-state Conversion Pathways in Evaporated All-perovskite Tandem Solar Cells
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中文总结 AI 辅助
本研究通过时间切片分析揭示顺序蒸发宽窄带隙钙钛矿的固态转化差异，据此开发1.26-1.96 eV吸收层，制成效率19.2%的首个蒸发全钙钛矿串联电池，并验证其长期稳定性。
中文摘要 AI 辅助
顺序热蒸发（sTE）正成为一种无溶剂制备高质量中带隙钙钛矿的途径，但其在用于全钙钛矿串联太阳能电池（TSCs）的混合卤化物宽带隙（WBG）和Sn-Pb窄带隙（NBG）吸收层中的应用，仍受限于对固态转化过程的不完全理解。在此，我们利用时间切片非原位分析，揭示了顺序蒸发WBG和NBG前驱体堆叠中发散的固态转化机制。在WBG堆叠中，含甲脒（FA）的物种渗透入无机模板，且Br/I的重新分布先于显著的三维钙钛矿形成。随后，光活性相从化学混合的储层中结晶，且绝对PbBr$_2$厚度（而非标称的PbBr$_2$/PbI$_2$比例）决定最终带隙。相比之下，在NBG堆叠中，甲脒碘化物沉积后早期形成富Pb钙钛矿相，限制了FA进一步渗透入埋藏的SnI$_2$前驱体。后续退火促进的晶格重组快于Sn/Pb互扩散，留下垂直组分梯度。在这些见解的指导下，我们开发了带隙覆盖1.26-1.96 eV的sTE吸收层，并展示了首个蒸发全钙钛矿串联太阳能电池，功率转换效率达到19.2%。封装的串联电池在65°C（ISOS-D-2）下经过1200小时后，平均保持初始效率的80%。这些结果确立了带隙特异的固态转化控制作为顺序蒸发钙钛矿串联光伏的设计原则。
英文摘要
Sequential thermal evaporation (sTE) is emerging as a solvent-free route to high-quality mid-bandgap perovskites, but its extension to mixed-halide wide-bandgap (WBG) and Sn-Pb narrow-bandgap (NBG) absorbers for all-perovskite tandem solar cells (TSCs) remains limited by an incomplete understanding of solid-state conversion. Here, using time-sliced ex situ analysis, we reveal divergent solid-state conversion mechanisms in sequentially evaporated WBG and NBG precursor stacks. In WBG stacks, formamidinium (FA)-containing species penetrate the inorganic template and Br/I redistribution precedes substantial three-dimensional perovskite formation. The photoactive phase then crystallizes from a chemically mixed reservoir, and absolute PbBr$_2$ thickness, rather than nominal PbBr$_2$/PbI$_2$ ratio, determines the final bandgap. In NBG stacks, by contrast, an early Pb-rich perovskite phase forms upon formamidinium iodide deposition, restricting further FA penetration into the buried SnI$_2$ precursor. Subsequent annealing promotes rapid lattice reorganization faster than Sn/Pb interdiffusion, leaving vertical compositional gradients. Guided by these insights, we develop sTE absorbers with bandgaps spanning 1.26-1.96 eV and demonstrate the first evaporated all-perovskite TSC, reaching a power conversion efficiency of 19.2%. Encapsulated tandems retain on average 80% of their initial efficiency after 1,200 h at 65 $^\circ$C (ISOS-D-2). These results establish bandgap-specific control of solid-state conversion as a design principle for sequentially evaporated perovskite tandem photovoltaics.
发表机构
- Empa – Swiss Federal Laboratories for Materials Science and Technology（瑞士联邦材料科学与技术研究院）
- Zurich University of Applied Sciences（苏黎世应用科学大学）
- ETH Zürich（苏黎世联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。
