Emergence and Control of Stacking Fault Formation during Nanoparticle Cation Exchange Reactions
Emergence and Control of Stacking Fault Formation during Nanoparticle Cation Exchange Reactions
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DOI：
10.1021/jacs.0c13072
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发表时间：
2021-01-25
影响因子：
15
通讯作者：
Schaak, Raymond E.
中科院分区：
文献类型：
--
作者：
Butterfield, Auston G.;Alameda, Lucas T.;Schaak, Raymond E.
阳离子交换反应改变了晶体的组成，同时保留了其他特征，包括晶体结构和形态。在许多情况下，阴离子亚晶格被认为是锁定在适当的位置，因为阳离子快速穿梭进出。在这里，我们提供的证据表明，阴离子的亚晶格可以移动显着在双阳离子交换反应。当铁锰矿Cu1.8S纳米棒中的Cu+阳离子与Zn 2+交换形成ZnS纳米棒时，出现高密度的层错。在阳离子交换过程中，紧密堆积的阴离子亚晶格的堆叠顺序在许多位置移位，以产生含有纤锌矿、锌钛矿和纤锌矿/锌钛矿多型体的混合物的纳米棒产物，所述纤锌矿/锌钛矿多型体含有有序排列的堆垛层错。控制阳离子交换速率的试剂浓度和反应温度充当可以将堆垛层错密度从高调节到低的合成杠杆，这是重要的，因为一旦引入堆垛层错，堆垛层错就不能通过热退火改性。这种通过阳离子交换的合成控制水平对于控制依赖于堆垛层错的存在和密度的性质是重要的。
Cation exchange reactions modify the composition of a nanocrystal while retaining other features, including the crystal structure and morphology. In many cases, the anion sublattice is considered to be locked in place as cations rapidly shuttle in and out. Here we provide evidence that the anion sublattice can shift significantly during nanocrystal cation exchange reactions. When the Cu+ cations of roxbyite Cu1.8S nanorods exchange with Zn2+ to form ZnS nanorods, a high density of stacking faults emerges. During cation exchange, the stacking sequence of the close-packed anion sublattice shifts at many locations to generate a nanorod product containing a mixture of wurtzite, zincblende, and a wurtzite/zincblende polytype that contains an ordered arrangement of stacking faults. The reagent concentration and reaction temperature, which control the cation exchange rate, serve as synthetic levers that can tune the stacking fault density from high to low, which is important because once introduced, the stacking faults could not be modified through thermal annealing. This level of synthetic control through nanocrystal cation exchange is important for controlling properties that depend on the presence and density of stacking faults.