Characterization of facial and meridional Alq3 thin films fabricated from physical vapor transport at high substrate temperatures

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/104178

Title:	Characterization of facial and meridional Alq3 thin films fabricated from physical vapor transport at high substrate temperatures
Authors:	楊仲準;Hung, Shang-Yu;Kao, Ruei-Lin;Lin, Ku-Yen;Yang, Chun-Chuen;Lin, Kuen-Song;Chao, Yu-Chiang;Wang, Jyh-Shyang;Shen, Ji-Lin;Chiu, Kuan-Cheng
Contributors:	理學院物理學系
Keywords:	Crystal structure;Evaporation;Optical properties;Organometallic compounds;Phase transitions;Thin films
Date:	2015-03-15
Issue Date:	2026-04-23 11:45:04 (UTC+8)
Publisher:	Elsevier BV;Elsevier B.V
Abstract:	摘要： During a thermal annealing process, the isomeric transformation from meridional (mer) into facial (fac) tris(8-hydroxyquinoline)-aluminum (Alq3) based on the infrared absorption was observed to be nearly complete around 375 °C. Then, in a physical vapor transport process with post-annealed fac-Alq3 as source powder (at source temperature of 375 °C), the effects from various substrate temperatures (Tsub from 285 to 346 °C) on the transformation from fac-Alq3 into mer-Alq3 isomers re-condensed on the substrate were studied again, and an isomeric transformation occurs at Tsub = 316 ± 2 °C. For Tsub below 316 ± 2 °C, the re-condensed mer-Alq3 isomers tend to aggregate to form close-packed micron-rods, which are composed of α-phase crystallites with an average coherent length L ∼ 46 nm. The photoluminescence (PL) spectra for these as-fabricated mer-Alq3 films show typical green emission. However, for Tsub above 316 ± 2 °C, the adsorbed fac-Alq3 molecules on the substrate preserve their corresponding isomeric structure from the post-annealed fac-Alq3 source and self-organize into flexible submicron-fibers. These samples are dominated by δ-phase crystallites with L ∼ 57 nm. The PL spectra for these as-fabricated fac-Alq3 films do emit blue luminescence. Besides, Raman scattering for these mer-Alq3 and fac-Alq3 molecules are also compared. [Display omitted] •Isomeric transformation from mer to fac-Alq3 is studied in annealing & PVT processes.•In PVT with fac-Alq3 source powder, isomeric transformation occurs at Tsub = 316 °C.•For Tsub > 316 °C, on the substrate the isomeric structure of fac-Alq3 is preserved.•For Tsub > 316 °C, the fabricated fac-Alq3 films with blue emission are δ-phase.•For Tsub < 316 °C, the fabricated mer-Alq3 films with green emission are α-phase. 出版者： Elsevier B.V 出版日期： 2015-03-15 出處： Materials chemistry and physics, 2015-03, Vol.154, p.100-106 版權： 2015 Elsevier B.V. 識別號： ISSN: 0254-0584 識別號： EISSN: 1879-3312 識別號： DOI: 10.1016/j.matchemphys.2015.01.051
Appears in Collections:	[Department of Physics] journal & Dissertation

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