Oxygen vacancy-rich vanadium-oxide hole-injection layer for high-performance OLEDs

IF 5.7 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Research Bulletin Pub Date : 2025-07-17 DOI:10.1016/j.materresbull.2025.113655

Soon-Gyu Lee , Ankhnybayar Batdelger , Hong-Gyu Park , Sang-Geon Park

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Abstract

Vanadium oxide (VOₓ) has gained attention as a promising hole-injection-layer material for organic light-emitting diodes (OLEDs); however, few studies have investigated the influence of VO_x impurities and oxygen vacancies on OLED performance. VO_x thin films of varying thicknesses were deposited on glass/indium tin oxide substrates via thermal evaporation to investigate their wettability, chemical composition, and electronic properties. Water-contact-angle (WCA) measurements revealed a transition from moderately hydrophilic to superhydrophilic behavior as the VOₓ thickness increased from 0.5 nm to 3 nm, which is attributed to the formation of oxygen vacancies. X-ray photoelectron spectroscopy confirmed the presence of V⁴⁺ and V⁵⁺ oxidation states, with the highest V⁵⁺ concentration at 2 nm, suggesting optimal oxygen-vacancy formation. Ultraviolet photoelectron spectroscopy demonstrated a stable work function (∼4.78–4.80 eV) across all thicknesses, and valence-band maximum variations indicated vacancy-mediated electronic transitions. The findings suggest that VOₓ enhances charge-injection properties in organic light-emitting diodes by reducing the hole-injection barrier, highlighting its potential as an effective hole-transport-layer material.

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用于高性能oled的富氧空穴氧化钒注入层

氧化钒（VOₓ）作为一种很有前途的有机发光二极管（oled）的空穴注入层材料受到了广泛的关注。然而，很少有研究探讨VOx杂质和氧空位对OLED性能的影响。通过热蒸发将不同厚度的VOx薄膜沉积在玻璃/氧化铟锡衬底上，研究其润湿性、化学成分和电子性能。当VOₓ的厚度从0.5 nm增加到3 nm时，水接触角（WCA）的测量结果表明，VO从中等亲水性转变为超亲水性，这是由于氧空位的形成。x射线光电子能谱证实了V⁴+和V 5 +氧化态的存在，其中V 5 +的浓度在2 nm处最高，表明最佳的氧空位形成。紫外光电子能谱显示在所有厚度上都有稳定的功函数（~ 4.78 ~ 4.80 eV），价带最大变化表明是空位介导的电子跃迁。研究结果表明，VOₓ通过减少空穴注入势垒来增强有机发光二极管的电荷注入特性，突出了其作为有效空穴传输层材料的潜力。

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来源期刊

Materials Research Bulletin 工程技术-材料科学：综合

CiteScore

9.80

自引率

5.60%

发文量

372

审稿时长

42 days

期刊介绍： Materials Research Bulletin is an international journal reporting high-impact research on processing-structure-property relationships in functional materials and nanomaterials with interesting electronic, magnetic, optical, thermal, mechanical or catalytic properties. Papers purely on thermodynamics or theoretical calculations (e.g., density functional theory) do not fall within the scope of the journal unless they also demonstrate a clear link to physical properties. Topics covered include functional materials (e.g., dielectrics, pyroelectrics, piezoelectrics, ferroelectrics, relaxors, thermoelectrics, etc.); electrochemistry and solid-state ionics (e.g., photovoltaics, batteries, sensors, and fuel cells); nanomaterials, graphene, and nanocomposites; luminescence and photocatalysis; crystal-structure and defect-structure analysis; novel electronics; non-crystalline solids; flexible electronics; protein-material interactions; and polymeric ion-exchange membranes.