Efficient structural modification of electron‐withdrawing substituents on Pt(II) complexes for red emitters: A theoretical study. (17th June 2020)

• Record Type: Journal Article
• Authors: Kang, Guo‐Jun; Ma, Jin‐Feng; Chen, Hai‐Yan; Ren, Xue‐Feng; Li, Ke
• Is Part Of: Applied organometallic chemistry. Volume 34:Number 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-06-17
• Subjects: 3MC -- DFT -- red emitters -- OLEDs; Organometallic chemistry -- Periodicals; Organometallic compounds -- Periodicals; 547.05
• DOI: 10.1002/aoc.5739
• Languages: English
• ISSNs: 0268-2605

Abstract

Abstract : In this study, the electronic structures and optical properties of a cyclometalated Pt(II) complex (M1) and a series of derivatives (M1–F, M1–CF3, and M1–CN) with electron‐withdrawing substituents (–F, –CF3, and –CN) at the carbazole moiety were theoretically investigated by density functional theory and time‐dependent density functional theory. The calculation results reveal that these Pt complexes display deep red phosphorescence emission above Λ = 640 nm. When the 3 MLCT/π → π* to triplet metal‐centered 3 MC/d–d state decay mechanism is taken into consideration, the nonradiative decay rate constant ( k nr ) decreased in the order M1 > M1–CF3 > M1–F > M1–CN. The 1 |HSOC |Sm > and kr values of M1‐F are similar with those of M1, however the Knr rate ofM1‐F is larger than that of M1. M1–F is expected to have improved quantum yields. Moreover, through the analyses of the HOMO/LUMO level and triplet energy, it is found that the introduction of –F and –CN substituents in M1 results in efficient energy transfer from the host material 4, 4′‐ N, N ′‐dicarbazole‐biphenyl to these complexes. In view of the electroluminescent applications in organic light‐emitting diodes, M1–F can serve as efficient deep‐red guest materials with improved electron injection and transport ability. Abstract : The effect of electron‐withdrawing substituents at the M1 on the radiative decay rate and thermal deactivation pathway are fully investigated by DFT and TD‐DFT methods. It is found that M1–F can serve as efficient deep‐red guest materials with improved electron injection and transport ability.