Synergistic Surface Passivation of CH3 NH3 PbBr3 Perovskite Quantum Dots with Phosphonic Acid and (3-Aminopropyl)triethoxysilane.
Synergistic Surface Passivation of CH3 NH3 PbBr3 Perovskite Quantum Dots with Phosphonic Acid and (3-Aminopropyl)triethoxysilane.
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DOI：
10.1002/chem.201805656
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发表时间：
2019-04
期刊：
影响因子：
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通讯作者：
Ke Xu;E. T. Vickers;Longshi Rao;Sarah A. Lindley;A’Lester C. Allen;Binbin Luo;Xueming Li;J. Zhang-J.
中科院分区：
文献类型：
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作者：
Ke Xu;E. T. Vickers;Longshi Rao;Sarah A. Lindley;A’Lester C. Allen;Binbin Luo;Xueming Li;J. Zhang-J.
CH3 NH3 PbBr3 钙钛矿量子点（PQD）是通过使用四种不同的直链烷基膦酸（PA）与（3-氨基丙基）三乙氧基硅烷（APTES）作为封端配体合成的。所得 PQD 通过 XRD、TEM、拉曼光谱、FTIR 光谱、UV/Vis、光致发光 (PL)、时间分辨 PL 和 X 射线光电子能谱 (XPS) 进行表征。 PA 链长可控制 PQD 尺寸（约 2.9-4.2 nm）和激子吸收带位置（λ=488-525 nm），较短的链长对应于较小的尺寸和更蓝的吸收。所有样品均表现出高 PL 量子产率（约 46-83 %）和高 PL 稳定性；这表明带隙陷阱态密度低且表面钝化有效。较小的 PQD 稳定性更高；这归因于较短的 PA 配体具有更好的溶解度和更少的空间位阻，从而实现了更好的钝化。基于FTIR、拉曼和XPS结果，提出Pb2+和CH3NH3+表面缺陷被R-PO3 2-或R-PO2(OH)-钝化，而Br-表面缺陷被R-NH3+部分钝化。本研究建立了 PA 和 APTES 配体的组合作为一种高效的双重钝化系统，用于通过主要离子键合协同钝化 PQD 的多个表面缺陷。
CH3 NH3 PbBr3 perovskite quantum dots (PQDs) are synthesized by using four different linear alkyl phosphonic acids (PAs) in conjunction with (3-aminopropyl)triethoxysilane (APTES) as capping ligands. The resultant PQDs are characterized by means of XRD, TEM, Raman spectroscopy, FTIR spectroscopy, UV/Vis, photoluminescence (PL), time-resolved PL, and X-ray photoelectron spectroscopy (XPS). PA chain length is shown to control the PQD size (ca. 2.9-4.2 nm) and excitonic absorption band positions (λ=488-525 nm), with shorter chain lengths corresponding to smaller sizes and bluer absorptions. All samples show a high PL quantum yield (ca. 46-83 %) and high PL stability; this is indicative of a low density of band gap trap states and effective surface passivation. Stability is higher for smaller PQDs; this is attributed to better passivation due to better solubility and less steric hindrance of the shorter PA ligands. Based on the FTIR, Raman, and XPS results, it is proposed that Pb2+ and CH3 NH3 + surface defects are passivated by R-PO3 2- or R-PO2 (OH)- , whereas Br- surface defects are passivated by R-NH3 + moieties. This study establishes the combination of PA and APTES ligands as a highly effective dual passivation system for the synergistic passivation of multiple surface defects of PQDs through primarily ionic bonding.