Organic Light-Emitting Diodes Based on a Binuclear Platinum(II) Complex

Saito, Kaori; Hamada, Y.; Takahashi, Hisakazu; Koshiyama, Tamami; Kato, Masako

doi:10.1143/jjap.44.l500

Cited by 32 publications

(19 citation statements)

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“…The cyclometalated or auxiliary ligands of these stacked binuclear Pt(II) complexes usually are C^N, [20][21][22][23][24] C^N^N, 25,26 N^N^N, [27][28][29] and C^C* (N-heterocyclic carbenes), 30,31 whose mononuclear Pt(II) complexes are highly emissive in dilute solution. The simple bidentate pyrazolate (pz), [21][22][23][24][25]28,31 pyridine-2-thiolate (pyt), 20 bis(diphenylphosphino)methane (dppm), 25,26 disulfur, 29 and amidinate 30 ligands with strong coordination ability are used as bridging ligands. It has been proved that the 3 MMLCT transition of stacked binuclear Pt(II) complexes is strongly dependent on the intramolecular Pt-Pt distances (2.8-4.0 Å) through the interacting 5d z 2 Pt(II) orbitals.…”

Section: Introductionmentioning

confidence: 99%

Syntheses, crystal structures, chirality and aggregation-induced phosphorescence of stacked binuclear platinum(ii) complexes with bridging Salen ligands

Shen

et al. 2019

Mater. Chem. Front.

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Section: Introductionmentioning

confidence: 99%

Syntheses, crystal structures, chirality and aggregation-induced phosphorescence of stacked binuclear platinum(ii) complexes with bridging Salen ligands

Shen

et al. 2019

Mater. Chem. Front.

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“…FPt2 is analogous to a binuclear complex with cyclometallated 2-phenylpyridyl (ppy) ligands recently prepared and used as a red dopant in OLEDs. [28,29] Synthesis and characterization data for FPt2 are given in the Experimental, and crystallographic data are given in the Supporting Information. The synthesis and photophysics of compounds 1-3 have been reported elsewhere.…”

Section: Introductionmentioning

confidence: 99%

Platinum Binuclear Complexes as Phosphorescent Dopants for Monochromatic and White Organic Light‐Emitting Diodes

Djurovich

Garon

et al. 2006

Adv Funct Materials

215

168

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Efficient blue‐, green‐, and red‐light‐emitting organic diodes are fabricated using binuclear platinum complexes as phosphorescent dopants. The series of complexes used here have pyrazolate bridging ligands and the general formula C∧NPt(μ‐pz)2PtC∧N (where C∧N = 2‐(4′,6′‐difluorophenyl)pyridinato‐N,C2′, pz = pyrazole (1), 3‐methyl‐5‐tert‐butylpyrazole (2), and 3,5‐bis(tert‐butyl)pyrazole (3)). The Pt–Pt distance in the complexes, which decreases in the order 1 > 2 > 3, solely determines the electroluminescence color of the organic light‐emitting diodes (OLEDs). Blue OLEDs fabricated using 8 % 1 doped into a 3,5‐bis(N‐carbazolyl)benzene (mCP) host have a quantum efficiency of 4.3 % at 120 Cd m–2, a brightness of 3900 Cd m–2 at 12 V, and Commission Internationale de L'Eclairage (CIE) coordinates of (0.11, 0.24). Green and red OLEDs fabricated with 2 and 3, respectively, also give high quantum efficiencies (∼ 6.7 %), with CIE coordinates of (0.31, 0.63) and (0.59, 0.46), respectively. The current‐density–voltage characteristics of devices made using dopants 2 and 3 indicate that hole trapping is enhanced by short Pt–Pt distances (< 3.1 Å). Blue electrophosphorescence is achieved by taking advantage of the binuclear molecular geometry in order to suppress dopant intermolecular interactions. No evidence of low‐energy emission from aggregate states is observed in OLEDs made with 50 % 1 doped into mCP. OLEDs made using 100 % 1 as an emissive layer display red luminescence, which is believed to originate from distorted complexes with compressed Pt–Pt separations located in defect sites within the neat film. White OLEDs are fabricated using 1 and 3 in three different device architectures, either with one or two dopants in dual emissive layers or both dopants in a single emissive layer. All the white OLEDs have high quantum efficiency (∼ 5 %) and brightness (∼ 600 Cd m–2 at 10 V).

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“….98 eV, 最低未占轨道(LUMO)能级(E LUMO )通过经验公式 E LUMO = (E red + 4.4) eV 计算得出 [15] . 然而, 双核环金属铂配合物的电化学氧化过程是一个典型的不可逆过程 [7] , 氧化电势(E ox )只能通过配合物固体膜的紫外可见吸收边峰和还原电势来估算 [16] . 因此,最高已占轨道(HOMO)的能级(E HOMO ) 可以根据氧化电势的估算值和经验公式 E HOMO = (E ox + 4.4) eV 计算得出 [15] .…”

Section: 电化学性能unclassified

“…与单核环金属铂(Ⅱ)配合物相比, 双核环金属铂配合物由于金属与配体间的配位作用以及铂-铂金属间的相互作用, 会发生强烈的金属-金属-配体的电荷转移(MMLCT) [5] , 通过调节环金属配体的结构, 可以实现长波红光发射或近红外光发射 [6~8] . Saito 课题组 [7] 报道了以双核铂配合物作为发光层的 OLED, 它的最大发射峰在 670 nm, 外量子效率为 3.4%. 随后, Ma 等 [8] 报道了一种以吡唑啉衍生物为桥连配体的双核铂配合物(dfppy)Pt(μ-Bu t -pz) 2 Pt(dfppy) OLED, 它的最大发射峰在 590 nm, 外量子效率达到 6.6%.…”

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