Rachkov Alexander G, Chalek Kevin, Yin Hang, Xu Mingjie, Holland Gregory P, Schimpf Alina M
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.
Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182, United States.
ACS Nano. 2024 Feb 7;18(7):5282-96. doi: 10.1021/acsnano.3c08962.
Copper phosphide (CuP) nanocrystals are promising materials for nanoplasmonics due to their substoichiometric composition, enabling the generation and stabilization of excess delocalized holes and leading to localized surface plasmon resonance (LSPR) absorption in the near-IR. We present three Cu-coupled redox chemistries that allow postsynthetic modulation of the delocalized hole concentrations and corresponding LSPR absorption in colloidal CuP nanocrystals. Changes in the structural, optical, and compositional properties are evaluated by powder X-ray diffraction, electronic absorption spectroscopy, P magic-angle spinning solid-state nuclear magnetic resonance spectroscopy, and elemental analysis. The redox chemistries presented herein can be used to access nanocrystals with LSPR energies of 660-890 meV, a larger range than has been possible through synthetic tuning alone. In addition to utilizing previously reported redox chemistries used for copper chalcogenide nanocrystals, we show that the largest structural and LSPR modulation is achieved using a divalent metal halide and trioctylphosphine. Specifically, nanocrystals treated with zinc iodide and trioctylphosphine have the smallest unit-cell volume (295.2 Å) reported for 6 CuP, indicating more Cu vacancies than have been previously observed. Overall, these redox chemistries present valuable insight into controlling the optical and structural properties of CuP.
磷化铜（CuP）纳米晶体因其亚化学计量组成而成为纳米等离子体学中有前景的材料，这种组成能够产生并稳定过量的离域空穴，从而在近红外区域产生局域表面等离子体共振（LSPR）吸收。我们展示了三种铜耦合氧化还原化学方法，可对胶体CuP纳米晶体中的离域空穴浓度和相应的LSPR吸收进行合成后调制。通过粉末X射线衍射、电子吸收光谱、P魔角旋转固态核磁共振光谱和元素分析来评估结构、光学和组成性质的变化。本文介绍的氧化还原化学方法可用于制备LSPR能量在660 - 890 meV之间的纳米晶体，这一范围比仅通过合成调节所能达到的范围更大。除了利用先前报道的用于铜硫属化物纳米晶体的氧化还原化学方法外，我们还表明，使用二价金属卤化物和三辛基膦可实现最大的结构和LSPR调制。具体而言，用碘化锌和三辛基膦处理的纳米晶体具有报道的6 CuP最小晶胞体积（295.2 Å），表明铜空位比以前观察到的更多。总体而言，这些氧化还原化学方法为控制CuP的光学和结构性质提供了有价值的见解。
