Synthesis and optoelectronic properties of a carbazole-modified platinum(<scp>ii</scp>) complex in polymer light-emitting devices
作者:Jian Luo、Yu Liu、Danyan Shi、Yafei Wang、Zhiyong Zhang、Junting Yu、Gangtie Lei、Qing Chen、Jianmin Li、Xianping Deng、Weiguo Zhu
DOI:10.1039/c1dt11346a
日期:——
To improve opto-electronic properties and efficiently suppress excimer emission, a phenylpyridine (ppy)-based platinum(II) complex (C16OCz-ppy)Pt(acac) was synthesized and characterized, where C16OCz-ppy is a 2-phenylpyridine derivative appending a carbazole moiety and three hexadecyloxy methyl units in the parent phenylpyridine, and acac is acetylacetone. This carbazole-modified platinum(II) complex exhibited good thermal stability and three times higher photoluminescent quantum yield than its parent (2-phenylpyridine-C2,N)(2,4-pentanedionato-O,O)platinum(II) complex [(ppy)Pt(acac)]. Single-emissive-layer polymer light-emitting devices using (C16OCZ-ppy)Pt(acac) as dopant and a blend of poly(N-vinylcarbazole) and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as host matrix presented a maximum current efficiency of 1.51 cd A−1, which was 1.5 times higher than that from the (ppy)Pt(acac)-doped device with the same device structure. Little excimer emission and minor aggregation emission were observed in the (C16OCZ-ppy)Pt(acac)-doped PLEDs at different dopant concentrations and applied voltages. This work indicates that introducing a carbazole and three hexadecyloxy methyl groups into the planar platinum(II) complex can reduce molecular aggregation and excimer emissions, thus resulting in high luminance and stable EL spectra in comparison with the parent (ppy)Pt(acac).
为了改善光电特性并有效抑制激发体发射,合成并表征了一种基于苯基吡啶的铂(II)配合物 (C16OCz-ppy)Pt(acac)。其中,C16OCz-ppy 是一种2-苯基吡啶衍生物,附加了一个咔唑基和三个十六烷氧基甲基单元,而 acac 是乙酰乙酮。该咔唑修饰的铂(II)配合物表现出良好的热稳定性,并且其光致发光量子产率是母体配合物(2-苯基吡啶-C2,N)(2,4-戊二酸二酮-O,O)铂(II)配合物 [(ppy)Pt(acac)] 的三倍。使用 (C16OCZ-ppy)Pt(acac) 作为掺杂剂,以及聚(N-乙烯基咔唑)和2-(4-联苯)-5-(4-叔丁基苯基)-1,3,4-噁二唑的混合物作为宿主基体的单发射层聚合物发光器件实现了最高的电流效率1.51 cd A−1,比同样结构的 (ppy)Pt(acac) 掺杂器件高出1.5倍。观察到在不同掺杂浓度和施加电压下,(C16OCZ-ppy)Pt(acac) 掺杂的PLED中出现了很少的激发体发射和轻微的聚集发射。这项工作表明,在平面铂(II)配合物中引入咔唑和三个十六烷氧基甲基单元可以减少分子聚集和激发体发射,从而与母体 (ppy)Pt(acac) 相比,实现高亮度和稳定的EL光谱。