Insights from density functional theory calculations into the effects of the adsorption and dissociation of water on the surface properties of zinc diphosphide (ZnP2) nanocrystals.
Insights from density functional theory calculations into the effects of the adsorption and dissociation of water on the surface properties of zinc diphosphide (ZnP2) nanocrystals.
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通过密度泛函理论计算了解水的吸附和离解对二磷化锌 (ZnP2) 纳米晶体表面性质的影响。
DOI：
10.1039/d1cp02784k
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Farkaš B
中科院分区：
文献类型：
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作者：
Farkaš B
磷化锌（ZnP 2和Zn 3 P2）由于其无毒和无毒的性质而成为用于光伏应用的新兴吸收剂材料。在此，我们提供了一个全面的表征的表面结构，组成，稳定性，形态，和电子性质的裸和水合/羟基化的低米勒指数表面的β-ZnP 2的密度泛函理论（DFT）计算的装置。水的吸附和解离的基本方面，包括吸附的几何形状，能量学，和结构参数沿着反应路径的机械见解进行了系统的表征。在干燥和潮湿的条件下的表面的稳定性进行了详细讨论，并提出了预测的水吸附相图。使用计算的表面能，我们推导出了在真空下和水合或羟基化后的β-ZnP 2纳米晶体的平衡形态。通过Bader电荷分析，从原子水平上揭示了β-ZnP 2表面氧化的起源，揭示了H2O和OH物种所结合的Zn位点由于电荷转移到吸附物种而发生氧化.吸附诱导的电子性质的变化之前和之后的水合/羟基化的特征在于功函数和偏态密度。结果强调了需要通过合成后有机官能化来保护β-ZnP 2纳米晶体在水存在下免受可能的氧化。
Zinc phosphides (ZnP2 and Zn3P2) are emerging absorber materials for photovoltaic applications owing to their abundancy and non-toxic nature. Herein, we provide a comprehensive characterisation of the surface structure, composition, stabilities, morphology, and electronic properties of both bare and hydrated/hydroxylated low-Miller index surfaces of β-ZnP2 by means of density functional theory (DFT) calculations. Mechanistic insights into the fundamental aspects of water adsorption and dissociation, including the adsorption geometries, energetics, and structural parameters along the reaction path are systematically characterised. The stabilities of the surfaces under dry and wet conditions are discussed in detail and the predicted phase diagrams for the water adsorption are presented. Using calculated surface energies, we have derived the equilibrium morphology of the β-ZnP2 nanocrystals under vacuum and upon hydration or hydroxylation. Atomic-level insights into the origin of the incipient oxidation of β-ZnP2 surfaces are provided through analysis of Bader charges, which reveal that the Zn sites to which H2O and OH species are bound undergo oxidation due to the transfer of charge to the adsorbed species. Adsorption-induced changes to the electronic properties before and after hydration/hydroxylation were characterised by the work function and partial density of states. The results highlight the need for protection of β-ZnP2 nanocrystals against possible oxidation in the presence of water through post-synthesis organic functionalisation.