Key Laboratory for Advanced Materials, Institute of Applied Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
Nanoscale. 2019 Feb 21;11(8):3527-3533. doi: 10.1039/c8nr09711a.
It has long been recognized that a small switching bias window, which is defined as the difference between the switch-on and switch-off voltages (Δ|VON - VOFF|), and a high ON/OFF current ratio would be greatly favorable to reduce the power consumption of memory devices and to decrease the information misreading rate in digital memory devices. In contrast to two-dimensional BP nanosheets, zero dimensional BP quantum dots (BPQDs) show more exciting physical and chemical properties. By using newly synthesized poly[(9,9-dioctyl-9H-fluorene)-alt-(4-(9H-carbazol-9-yl)aniline)] (PFCz-NH2) as the synthetic precursor, a highly soluble diazotated polymer, PFCz-N2+BF4-, was successfully synthesized and used to react with BPQDs under aqueous conditions to give the first conjugated polymer covalently functionalized BPQDs (PFCz-g-BPQDs). The as-prepared Al/PFCz-g-BPQDs/ITO device exhibits excellent nonvolatile rewritable memory performance, with a large ON/OFF current ratio (>107) and low switch-on/off voltages (-0.89/+1.95 V). In contrast, the Al/PFCz-NH2 : BPQDs blend/ITO device also shows a rewritable memory effect, but its ON/OFF current ratio and Δ|VON - VOFF| value are found to be 3 × 103 and 5.47 (Δ|+2.53-2.94|), respectively. This work, which offers an easy one-step strategy for direct covalent functionalization of BPQDs, opens a way to explore more applications of BPQDs.
长期以来，人们一直认为小的开关偏置窗口（定义为导通电压和关断电压之间的差值（Δ|VON-VOFF|））和高的导通/关断电流比将大大有利于降低存储器件的功耗并降低数字存储器件中的信息误读率。与二维 BP 纳米片相比，零维 BP 量子点（BPQDs）表现出更令人兴奋的物理和化学性质。通过使用新合成的聚[(9,9-二辛基-9H-芴)-交替-(4-(9H-咔唑-9-基)苯胺)]（PFCz-NH2）作为合成前体，成功合成了高度可溶的重氮聚合物 PFCz-N2+BF4-，并在水相条件下与 BPQDs 反应，得到了第一个共轭聚合物共价功能化的 BPQDs（PFCz-g-BPQDs）。所制备的 Al/PFCz-g-BPQDs/ITO 器件表现出优异的非易失性可重写存储性能，具有大的导通/关断电流比（>107）和低的导通/关断电压（-0.89/+1.95 V）。相比之下，Al/PFCz-NH2：BPQDs 混合物/ITO 器件也表现出可重写的存储效应，但其导通/关断电流比和Δ|VON-VOFF|值分别为 3×103 和 5.47（Δ|+2.53-2.94|）。这项工作提供了一种直接共价功能化 BPQDs 的简便一步策略，为探索 BPQDs 的更多应用开辟了道路。
