Highly efficient deep-red/near-infrared D-A chromophores based on naphthothiadiazole for OLEDs applications

作者：Li, Ya; Yao, Jingwen; Wang, Cong; Zhou, Xuehong; Xu, Yuwei; Hanif, Muddasir; Qiu, Xu; Hu, Dehua^*; Ma, Dongge^*; Ma, Yuguang^*

来源：Dyes and Pigments, 2020, 173: 107960.

DOI：10.1016/j.dyepig.2019.107960

• Naphthothiadiazole
• D-A chromophores
• DR/NIR materials
• HLCT
• OLEDs

Donor-acceptor (D-A) chromophores are an important class of deep-red/near-infrared (DR/NIR) materials. However, efficient D-A DR/NIR fluorescent emitters are rare due to the intrinsic charge-transfer excited-state. In this paper, two novel D-A-type DR/NIR fluorescent emitters with triphenylamine (TPA, donor), naph-thothiadiazole (NZ, acceptor), pyrimidine (2TPA-NZN) and benzene (2TPA-BZN) as the pi-bridge, are designed and synthesized. The photophysical study and theoretical analysis revealed that the emissive-state of the two materials has hybridized local and charge-transfer (HLCT) characters. This characteristic caused high photoluminescent quantum yield (PLQY) both in solution and doped film. The 2TPA-BZN with a more rigid molecular structure exhibits a lower non-radiative rate constant (k(nr)), resulting in relatively higher PLQY as compared with the 2TPA-NZN. The doped organic light-emitting diodes (OLEDs) devices based on these materials demonstrated excellent maximum external quantum efficiency (EQE(max) > 5.0%) and the emission peak around 665 nm.