3,3′-Bicarbazole-Based Host Molecules for Solution-Processed Phosphorescent OLEDs

Kim, Jungwoon; Lee, Suhan; Lee, Jaemin; Lim, Eunhee; Jung, Bernhard

doi:10.3390/molecules23040847

Cited by 10 publications

(5 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Carbazoles (Cz), 2,2′-connected diphenylamines, are inextricable heteroaromatic skeletons in the fields of organic, medicinal, and polymer chemistry . Very importantly, bicarbazoles (BCz) are found to showcase potential application in organic electronics and photonics, sensing, and memory devices because of their advantageous/exemplary characteristics, such as low ionization potentials, excellent glassy nature ( T g ), and blue luminescence, etc . In particular, they have been identified as important bioskeletons in several natural products .…”

Section: Introductionmentioning

confidence: 99%

Oxidative Coupling of Carbazoles: A Substituent-Governed Regioselectivity Profile

et al. 2018

View full text Add to dashboard Cite

Oxidative C−C coupling of carbazoles possessing various substituents is demonstrated in the presence of organic (metal-free) recyclable oxidants, such as DDQ or CA/H + , for accessing bicarbazole regioisomers. Differently substituted carbazoles are examined to showcase regioselective discrimination (3,3′-versus 1,3′-bicarbazoles) and preferences based on sterics and electronics in oxidative coupling. Finally, a mechanism that involves the carbazole radical cation has been traced (evidenced) and proposed on the basis of the UV−vis−NIR absorption and EPR spectroscopy results. This study underlines the strategic chemical preparation of a series of bicarbazoles in an efficient manner.

show abstract

Section: Introductionmentioning

confidence: 99%

Oxidative Coupling of Carbazoles: A Substituent-Governed Regioselectivity Profile

et al. 2018

View full text Add to dashboard Cite

show abstract

“…In traditional structures, all UEMLs are located at the interface with the highest expected concentrations of excitons, which can result in severe interface accumulation and exciton annihilation [23,52]. Therefore, the use of UEMLs in WOLEDs at high brightness levels poses a significant challenge due to efficiency roll-off issues [53].…”

Section: Phosphorescent Doping Woleds With Uemlsmentioning

confidence: 99%

Progress in Research on White Organic Light-Emitting Diodes Based on Ultrathin Emitting Layers

Zhao,

Hu,

Kong

et al. 2024

Micromachines

View full text Add to dashboard Cite

White organic light-emitting diodes (WOLEDs) hold vast prospects in the fields of next-generation displays and solid-state lighting. Ultrathin emitting layers (UEMLs) have become a research hotspot because of their unique advantage. On the basis of simplifying the device structure and preparation process, they can achieve electroluminescent performance comparable to that of doped devices. In this review, we first discuss the working principles and advantages of WOLEDs based on UEML architecture, which can achieve low cost and more flexibility by simplifying the device structure and preparation process. Subsequently, the successful applications of doping and non-doping technologies in fluorescent, phosphorescent, and hybrid WOLEDs combined with UEMLs are discussed, and the operation mechanisms of these WOLEDs are emphasized briefly. We firmly believe that this article will bring new hope for the development of UEML-based WOLEDs in the future.

show abstract

“…Their popularity is derived from their low oxidation potentials (they are electron-rich), planar aromatic skeletons (resulting in hole mobility and hole transporting ability), and emissive behavior (singlet and triplet energies). − We wondered whether 3,3′-bicarbazole, a dimer of carbazole with an in-built twist, might impart superior optoelectronic properties, such as a more suitable HOMO energy level and improved hole mobility. Indeed, 3,3′-bicarbazoles have been used widely as phosphorescent dopants in PhOLEDs − and, recently, N , N ′-bicarbazoles have been demonstrated as candidates for use in PSCs …”

Section: Introductionmentioning

confidence: 99%

Forming a Metal-Free Oxidatively Coupled Agent, Bicarbazole, as a Defect Passivation for HTM and an Interfacial Layer in a p–i–n Perovskite Solar Cell Exhibits Nearly 20% Efficiency

et al. 2019

View full text Add to dashboard Cite

In this study, we synthesized three simple and inexpensive (34−120 USD/g) 3,3′-bicarbazole-based hole transporting materials (BC-HTMs; NP-BC, NBP-BC and PNP-BC) through a metal-free oxidative coupling, in excellent yields (≥95%). These bicarbazoles contain phenylene or biphenylene substituents on the carbazole N atom, with extended π-conjugation achieved through phenylene units at the 6,6′-positions of the bicarbazole. When using NBP-BC as a dopant-free HTM in a p−i−n perovskite solar cell (PSC), we achieved a power conversion efficiency (PCEs) of 12.22 ± 0.54% under AM 1.5G conditions (100 mW cm −2 ); this PCE was comparable to that obtained when using PEDOT:PSS as the HTM (11.23 ± 1.02%). BC-HTMs showed the large grain size (μm) of perovskite than PEDOT:PSS-based, due to defect passivation on indium tin oxide (ITO) substrate and good hydrophobicity. Furthermore, we realized highly efficient and stable PSCs when using the p−i−n device structure ITO/NiO x /NP-BC/perovskite/PC 61 BM/BCP/Ag. The bifacial defect passivation effect of the interfacial layer improved the grain size of the perovskite layer and also enhanced the performance; the best performance of the NiO x /NP-BC device was characterized by a short-circuit current density (J sc ) of 22.38 mA cm −2 , an open-circuit voltage (V oc ) of 1.09 V, and a fill factor (FF) of 79.9%, corresponding to an overall PCE of almost 20%. This device structure has competitive potential because its performance is comparable to that of the record-high-efficiency PSCs. Under an Ar atmosphere, the PCE of the NiO x /NP-BC PSC device decayed by only 4.55% after 168 h; it retained 90.80% of its original PCE after 1000 h. A morphological study revealed that the films of the BC-HTMs were indeed smooth and hydrophobic and that the perovskite films spin-coated upon them were uniform and featured large grains (micrometer scale). Time-resolved photoluminescence (TRPL) spectra of the perovskite films suggested that the hole extraction capabilities of the NiO x /BC-HTMs were better than that of the bare NiO x . The superior film morphologies of the NiO x /BC-HTMs were responsible for the performances of their devices being comparable to those of bare NiO x -based PSCs.

show abstract

3,3′-Bicarbazole-Based Host Molecules for Solution-Processed Phosphorescent OLEDs

Cited by 10 publications

References 29 publications

Oxidative Coupling of Carbazoles: A Substituent-Governed Regioselectivity Profile

Oxidative Coupling of Carbazoles: A Substituent-Governed Regioselectivity Profile

Progress in Research on White Organic Light-Emitting Diodes Based on Ultrathin Emitting Layers

Forming a Metal-Free Oxidatively Coupled Agent, Bicarbazole, as a Defect Passivation for HTM and an Interfacial Layer in a p–i–n Perovskite Solar Cell Exhibits Nearly 20% Efficiency

Contact Info

Product

Resources

About