Potential cerium precursors for blue colour in thin film electroluminescent devices grown by atomic layer epitaxy

Leskelä, Tuula; Vasama, Kirsi; Härkönen, Gitte; Sarkio, Pertti; Lounasmaa, Mauri

doi:10.1002/(sici)1099-0712(199607)6:4<169::aid-amo234>3.0.co;2-7

Cited by 15 publications

(17 citation statements)

References 2 publications

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“…The large size of the alkalineearth metals, especially for barium, results in coordinative unsaturation, and barium tetramethylheptanedionate cannot be described by a simple formula such as Ba(thd) 2 . 3 By contrast with the monomeric nature of the yttrium and copper derivatives, barium tetramethylheptanedionate actually corresponds to a tetramer [Ba 4 (thd) 8 ], 17,18 to pentanuclear clusters [Ba 5 (m 5 -X)(thd) 9 (H 2 O) n ] (X = OH, n = 3; 19 X = C1, n = 7) 20 or [Ba 5 (thd) 9 (piv)] (piv = pivalate = tBuCO 2 ), 21 or to the hexamer [Ba 6 (thd) 12 2 ]. The compound was prepared in a queous medium using Ba(OH) 2 and recrystallized from methanol, 23 a synthetic procedure which was also reported to lead to [Ba 5 (m 5 -OH)(thd) 9 (H 2 O) 3 ] by recrystallization in pentane.…”

Section: B-diketonates and Their Adductsmentioning

confidence: 99%

“…Although they dissociate during sublimation or in diglyme ( 1 H NMR evidence), they are interesting alternatives to [Ba 4 (thd) 8 ] in terms of handling, the chelating Lewis bases precluding facile coordination of water and/or other reactants.…”

Section: Design Of Precursors For Liquiddelivery Techniquesmentioning

confidence: 99%

“…[Ba 2 (thd) 4 (bipy) 2 ] is however a better choice than [Ba(thd) 2 (o-phen) 2 ] in terms of solubility and properties of the coatings. Use of commercial, non-distilled diglyme (containing dioxygen) leads rapidly to insoluble barium species if [Ba 4 (thd) 8 ] is used, thus modifying the composition (stoichiometry) of the feed solution, and to barium peroxo species. 24,25 Better stability toward hydrolysis is observed with Ba(thd) 2 complexes where barium displays higher coordination numbers.…”

Section: Design Of Precursors For Liquiddelivery Techniquesmentioning

confidence: 99%

“…However, meeting the criteria is still challenging for some elements, e.g. for barium 4,5 or cerium [6][7][8] oxide precursors, and significant deficiencies still exist with respect to vapor pressure and vapor-pressure stability. Indeed, a low charge on a metal ion combined with a large ionic radius (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Trends in precursor design for conventional and aerosol‐assisted CVD of high‐Tc superconductors

Hubert‐Pfalzgraf

Guillon

1998

Appl. Organometal. Chem.

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Conventional MOCVD techniques require molecules displaying volatility and constant vapor pressure. Metal oxide precursors, i.e., b-diketonates, or classical or functionalized metal alkoxides are mostly solids. The various approaches used to tailor volatility are discussed with barium derivatives as an example. The relationships between sublimation temperature and molecular weight suggest that volatility can be optimized on the basis of molecular weight.Aerosol-assisted CVD (AACVD) can use a larger range of precursors since volatility is no longer crucial. The solvent is an undesired ballast in a CVD process. High solubility of the precursors in the selected solvent is thus desirable. 'Stability' here includes the absence of precipitation which would change the stoichiometry of the feed solution for multicomponent oxides. Precipitation is often promoted by hydrolysis; stability toward moisture is thus desirable. The use of mixtures of precursors based on different ligands (b-diketonates, bketoesterates, alkoxides) can lead to ligand exchange reactions giving homometallic species, sometimes of low solubility, or mixed-metal species by self-assembly, thus improving solubility and stability toward moisture. These aspects are illustrated in compositions related to high-T c superconductors.

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Section: B-diketonates and Their Adductsmentioning

confidence: 99%

Section: Design Of Precursors For Liquiddelivery Techniquesmentioning

confidence: 99%

Section: Design Of Precursors For Liquiddelivery Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Trends in precursor design for conventional and aerosol‐assisted CVD of high‐Tc superconductors

Hubert‐Pfalzgraf

Guillon

1998

Appl. Organometal. Chem.

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

Trends in precursor design for conventional and aerosol-assisted CVD of high-Tc superconductors

Hubert‐Pfalzgraf

Guillon

1998

Appl. Organometal. Chem.

View full text Add to dashboard Cite

Conventional MOCVD techniques require molecules displaying volatility and constant vapor pressure. Metal oxide precursors, i.e., β‐diketonates, or classical or functionalized metal alkoxides are mostly solids. The various approaches used to tailor volatility are discussed with barium derivatives as an example. The relationships between sublimation temperature and molecular weight suggest that volatility can be optimized on the basis of molecular weight. Aerosol‐assisted CVD (AACVD) can use a larger range of precursors since volatility is no longer crucial. The solvent is an undesired ballast in a CVD process. High solubility of the precursors in the selected solvent is thus desirable. ‘Stability’ here includes the absence of precipitation which would change the stoichiometry of the feed solution for multicomponent oxides. Precipitation is often promoted by hydrolysis; stability toward moisture is thus desirable. The use of mixtures of precursors based on different ligands (β‐diketonates, β‐ketoesterates, alkoxides) can lead to ligand exchange reactions giving homometallic species, sometimes of low solubility, or mixed‐metal species by self‐assembly, thus improving solubility and stability toward moisture. These aspects are illustrated in compositions related to high‐Tc superconductors. Novel copper, yttrium, cerum(IV), barium‐copper, yttrium‐copper and praseodynium‐copper species are reported. © 1998 John Wiley & Sons, Ltd.

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Volatile Metal β‐Diketonates: ALE and CVD precursors for electroluminescent device thin films

Karinen

Niinistou²

1997

Chemical Vapor Deposition

138

113

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The use of volatile P-diketonate chelates as precursors for the deposition of thin films for electroluminescent devices is reviewed. Alternating current thin film electroluminescent (ACTFEL) devices consist of an emitting layer sandwiched between two dielectric layers, together with conducting and buffer layers. Besides various physical deposition techniques, the commonly applied methods for preparing thin films are chemical vapor deposition (CVD) and its particular variant atomic layer epitaxy (ALE). Alkaline earth P-diketonates are used as precursors for deposition of the semiconducting alkaline earth sulfide and thiogallate films that provide the matrix in emissive layers, while P-diketonates of lanthanides and a few other metals (Mn, Na, K) are precursors for dopants and codopants producing colors. P-Diketonate precursors can also be used for the preparation of dielectric alkaline earth titanate and oxide layers. Current research on thin film electroluminescent materials is focused on improving the blue color produced by cerium doping of alkaline earth sulfide and thiogallate matrices. The synthesis and properties of P-diketonate chelates and the growth and characterization of the thin films obtained with them are presented and discussed. This review of precursors for TFEL materials is also relevant for other materials, including oxide superconductors.

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Potential cerium precursors for blue colour in thin film electroluminescent devices grown by atomic layer epitaxy

Cited by 15 publications

References 2 publications

Trends in precursor design for conventional and aerosol‐assisted CVD of high‐Tc superconductors

Trends in precursor design for conventional and aerosol‐assisted CVD of high‐Tc superconductors

Trends in precursor design for conventional and aerosol-assisted CVD of high-Tc superconductors

Volatile Metal β‐Diketonates: ALE and CVD precursors for electroluminescent device thin films

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