High-performance near-infrared (NIR) polymer light-emitting diodes (PLEDs) based on bipolar Ir(iii)-complex-grafted polymers. Issue 1 (27th November 2020)

• Record Type: Journal Article
• Authors: Li, Wentao; Wang, Baowen; Miao, Tiezheng; Liu, Jiaxiang; Fu, Guorui; Lü, Xingqiang; Feng, Weixu; Wong, Wai-Yeung
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 1(2021)
• Page Start: 173
• Page End: 180
• Publication Date: 2020-11-27
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0tc04377j
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Despite the cost-effective and large-area scalable advantages of NIR-PLEDs based on iridium(iii )-complex-doped polymers, the intrinsic phase-separation issue leading to inferior device performance is difficult to address. Abstract : Despite the cost-effective and large-area scalable advantages of NIR-PLEDs based on iridium(iii )-complex-doped polymers, the intrinsic phase-separation issue leading to inferior device performance is difficult to address. In this study, taking the vinyl-functionalized [Ir(iqbt)2 (vb-ppy)] (Hqibt = 1-(benzo[ b ]-thiophen-2-yl)-isoquinoline; vb-Hppy = 2-(4′-vinylbiphenyl-4-yl)pyridine) as the polymerized complex monomer, two series of Ir(iii )-complex-grafted polymers Poly(NVK-co-[Ir(iqbt)2 (vb-ppy)]) and Poly((vinyl-PBD)-co-NVK-co-[Ir(iqbt)2 (vb-ppy)]) (NVK = N -vinyl-carbazole; vinyl-PBD = 2-(4-( tert -butyl)phenyl)-5-(4′-vinyl-[1, 1′-biphenyl]-4-yl)-2, 5-dihydro-1, 3, 4-oxadiazole) are obtained, respectively. Moreover, by using the bipolar Ir(iii )-complex-grafted polymer further doped or grafted with an electron-transport unit as the emitting layer (EML), reliable NIR-PLEDs are realized. In particular based on the concurrent covalent-linkages of both the Ir(iii )-complex and the vinyl-PBD towards the carrier-balanced NIR-PLED-III, the achievement of an almost negligible (<5%) efficiency roll-off does not sacrifice the attractive efficiency ( η maxEQE = 3.6%). This finding makes bipolar Ir(iii )-complex-grafted polymers a good platform to achieve high-performance NIR-PLEDs.