Institute for the Chemistry of Organometallic Compounds (CNR-ICCOM), Via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy.
Synchrotron SOLEIL L'orme des Merisiers, 91192, Gif-sur-Yvette, France.
Chempluschem. 2023 Feb;88(2):e202200457. doi: 10.1002/cplu.202200457.
Layered black phosphorus (BP) is endowed with peculiar chemico-physical properties that make it a highly promising candidate in the field of electronics. Nevertheless, as other 2D materials with atomic scale thickness, it suffers from easy degradation under ambient conditions. Herein, it is shown that the functionalization of BP with preformed and in situ grown Ni NPs, affects the electronic properties of the material. In particular, Ni functionalization performed in situ leads to a narrowing of the average BP band gap from 1.15 to 0.95 eV and to a marked shift in the conduction band maximum from -0.33 V to -0.07 V, which, in turn, improve the ambient stability. Structural studies carried out by XAS can well distinguish the two nanohybrids and reveal that once Ni NPs are grown on BP nanosheets, a Ni-P coordinative bond is formed, featuring a short Ni-P distance of 2.27 Å, which is not observed when preformed Ni NPs are immobilized on BP. Comparing the XANES and EXAFS spectra of fresh and aged samples of both nanohybrids, suggests that the interaction between Ni and P atoms results in a stabilization effect exerted via a dual electronic and redox mechanism, that infers a much superior ambient stability to BP, even if the surface functionalization is far to achieve a full coverage.
层状黑磷 (BP) 具有独特的理化性质，使其成为电子领域极具前景的候选材料。然而，与其他具有原子级厚度的二维材料一样，BP 在环境条件下容易降解。本文表明，通过预先形成和原位生长的 Ni NPs 对 BP 进行功能化，会影响材料的电子性质。特别是，原位进行的 Ni 功能化会使 BP 的平均能带隙从 1.15 eV 缩小到 0.95 eV，并使导带最大值从 -0.33 V 显著移动到 -0.07 V，这反过来又提高了环境稳定性。通过 XAS 进行的结构研究可以很好地区分这两种纳米复合材料，并表明一旦 Ni NPs 生长在 BP 纳米片上，就会形成 Ni-P 配位键，其 Ni-P 距离为 2.27 Å，而在将预先形成的 Ni NPs 固定在 BP 上时则观察不到这种情况。比较两种纳米复合材料的新鲜和老化样品的 XANES 和 EXAFS 谱表明，Ni 和 P 原子之间的相互作用通过双电子和氧化还原机制产生了稳定效应，这推断出即使表面功能化远未达到完全覆盖，BP 的环境稳定性也大大提高。
