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Tailoring Molecular Precursors for Multicomponent Oxides
Hubert-Pfalzgraf, Liliane G. The Korean Ceramic Society 2000 The Korean journal of ceramics Vol.6 No.4
Simple ways to build up mixed-metal molecules which can act as potential single-source precursors to multimetallic oxides are reviewed. Emphasis is given to Lewis acid-base reactions between metal alkoxides M(OR)/sub n/, and between metal alkoxides and more accessible oxide precursors, carboxylates M(O₂CR)/sub n/ and β-diketonates M(β-dik)/sub n/. Characterization of the precursors is achieved in the solid state (single crystal X-ray diffraction, FT-IR) and by multinuclear NMR in solution. The reactions proceed toward the formation of aggregates in which the different metals display their usual coordinations numbers, often six for transition metals, as shown. Strategies for fixing the stoichiometry between the metals are developed. The reactivity of the MM species (dissociation, effects of chemical modifiers, of other metallic species, hydrolytic or non-hydrolytic condensation, etc.) will be indicated. Transformations into oxides are illustrated on precursors for titanates or niobates.
$Pb(Zn_{0.6}Mg_{0.4})_{1/3}Nb_{2/3}O_3$[PZMN] 합성시 전구체 혼합방법에 따른 반응 경로변화
김봉철,김정주,김남경,조상희 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.5
Variations of reaction sequence of $Pb(Zn_{0.6}Mg_{0.4})_{1/3}Nb_{2/3}O_3$[PZMN] with precusor mixing methods were ex-amined using X-ray diffraction and dielectric characteristics. In the present study three different types of precursor mixing methods (oxide mixing PbO+$ZnNb_2O_6+MgNb_2O_6$[Zn+MN] and PbO+(Zn,Mg)$Nb_2O_6$[ZMN] precursor mixing) were adopted. When the oxide mixing method was used for the PZMN synthesis a Zn-rich perovskite phase and pyrochlore phase were formed. Compared with PbO+ZN+MN precursor mixing method the PbO-ZMN precursor led to a lowering of the formation temperature for perovskite sin-gle phase. These variation of composition and formation temperature of the perovskite phase were dis-cussed in terms of the difference in the solid-reaction requence between these three different types of pre-cursor mixing.
안종기,심섭,강고루,오남근,김진태,함성호,윤주영 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
ZrO2 세가지 상을 가지며 그 중 tetragonal phase가 이론적으로 가장 높은 값을 갖는 것으로 알려져 있다 (k ~ 47). 하지만 실제로는 tetragonal phase가 열역학적으로 불안정하므로 Si, Al, Ge 등의 작은 이온반경을 가진 4가 원소를 ZrO2에 적당히 doping하면 이를 안정화시킬 수 있으며, 최근 연구결과에 따르면, dopant의 농도에 의해 ZrO2 박막의 phase stability 및 dieletric constant 값이 결정됨이 보고되었다. 이 때문에 high-k tetragonal ZrO2 박막을 얻기 위해서는 dopant의 농도를 정확히 제어하는 것이 무엇보다 중요하다. 현재 이러한 Al doped high-k tetragonal ZrO2 박막을 형성하기 위해 atomic layer deposition (ALD) 등의 방법이 사용되고 있는데 증착된 Al-doped ZrO2 박막의 Al dopant 농도는 증착 후에나 확인할 수 있어 원하는 조성의 박막을 얻는 데에는 근본적인 한계가 있었다. 본 연구는 distillation 방법을 이용하여 precursor의 기상을 액상으로 포집하여 H-NMR 분석을 통하여 조성을 확인하였다. 향후 기상의 조성을 측정방법을 통해 조성을 확인한다면, ALD 증착시, 박막의 조성을 좀 더 쉽게 제어할것으로 기대된다.
Lee, Donmin,Jung, Yen-Sook,Heo, Youn-Jung,Lee, Sehyun,Hwang, Kyeongil,Jeon, Ye-Jin,Kim, Jueng-Eun,Park, Jiyoon,Jung, Gun Young,Kim, Dong-Yu American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.18
<P>Recently, many kinds of printing processes have been studied to fabricate perovskite solar cells (PeSCs) for mass production. Among them, slot-die coating is a promising candidate for roll-to-roll processing because of high-throughput, easy module patterning, and a premetered coating system. In this work, we employed mixed lead precursors consisting of PbAc<SUB>2</SUB> and PbCl<SUB>2</SUB> to fabricate PeSCs via slot-die coating. We observed that slot-die-coated perovskite films based on the mixed lead precursors exhibited well-grown and uniform morphology, which was hard to achieve by using only a single lead source. Consequently, PeSCs made with this precursor system showed improved device performance and reproducibility over single PbAc<SUB>2</SUB>. Lastly, a large-area module with an active area of 10 cm<SUP>2</SUP> was fabricated with a power conversion efficiency of 8.3%.</P> [FIG OMISSION]</BR>