Dibenzo[g,p]chrysene: A new platform for highly efficient red phosphorescent organic light-emitting diodes

Accepted Manuscript Dibenzo[g,p]chrysene: A new platform for highly efficient red phosphorescent organic light-emitting diodes Xiang-Yang Liu, Xun Tang, Yue Zhao, Danli Zhao, Jian Fan, Liang-Sheng Liao PII:

S0143-7208(17)31099-9

DOI:

10.1016/j.dyepig.2017.06.036

Reference:

DYPI 6057

To appear in:

Dyes and Pigments

Received Date: 12 May 2017 Revised Date:

14 June 2017

Accepted Date: 14 June 2017

Please cite this article as: Liu X-Y, Tang X, Zhao Y, Zhao D, Fan J, Liao L-S, Dibenzo[g,p]chrysene: A new platform for highly efficient red phosphorescent organic light-emitting diodes, Dyes and Pigments (2017), doi: 10.1016/j.dyepig.2017.06.036. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

Dibenzo[g,p]chrysene: A New Platform for Highly Efficient Red Phosphorescent Organic Light-Emitting Diodes

Xiang-Yang Liu,†a Xun Tang,†a Yue Zhao,b Danli Zhao,a Jian Fan,*,a,c

a

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Liang-Sheng Liao,a,c

Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute

of Functional Nano & Soft Materials (FUNSOM) & Collaborative Innovation Center

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of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P.R. China. b

Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry,

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School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210023, China. c

Institute of Organic Optoelectronics (IOO), JITRI, Suzhou, Jiangsu 215212, China.

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E-mail: [email protected].

† The two authors contribute equally to this paper.

* Corresponding authors.

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E-mail addresses: [email protected] (F. Jian)

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Tel.: +86-0512-65880191

Abstract

One polycyclic aromatic hydrocarbon compound, 3,6,11,14-tetraphenyldibenzo[g,p]chrysene (TPDBC), was designed, synthesized, and fabricated in a red phosphorescent organic light-emitting diode (PHOLED) with a maximum external quantum efficiency (EQE) of 14.4%, which represented the first report of a dibenzo[g,p]chrysene motif as the building block for host materials. It was conjectured that dibenzo[g,p]chrysene may serve as a next generation molecular platform which is readily functionalizable for the preparation of electroactive materials for applications in the emerging areas of molecular electronics.

Keywords OLED; Dibenzo[g,p]chrysene; Host material; Rigid building block; Polycyclic Aromatic 1

ACCEPTED MANUSCRIPT Hydrocarbon;

1. Introduction Even since the dawn of organic light-emitting diodes (OLEDs) in 1987,[1] there has been an ongoing quest to develop stable and efficient devices.[2-8] This exploration is not over yet, mainly

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because highly efficient and long-lifetime OLEDs remain key issues.[9-11] Within a typical OLED, holes and electrons are combined together in a light-emitting layer to form excitons with different spin character (singlet state (S) or triplet state (T)). Since the ratio of singlet and triplet is approximately 1:3, the maximum internal quantum efficiency (IQE) of conventional fluorescent OLEDs will be limited up to 25% by harvesting solely singlet excitons.[12,13] Fortunately, in 1998

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the phosphorescent materials were developed, where the introduction of heavy transition metals such as Pt, Ir and Os led to very strong intramolecular spin-orbit coupling, thus breaking the law of spin statistics.[12,13] So the phosphorescent organic light-emitting diodes (PHOLEDs) can

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achieve nearly 100% IQE through harvesting both singlet and triplet excitons. For PHOLEDs, to avoid a self-aggregation quenching process and the triplet-involved quenching effects, the phosphors are normally doped into host matrices.[14,15] Therefore, the hosts play an important role to achieve efficient PHOLEDs. There are several requirements needed to be met for the development of high efficient host materials, such as high triplet energy, good charge transporting ability, suitable highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital

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(LUMO) level, and good thermal stability.[9-11]

Discotic-type polycyclic aromatic hydrocarbons (DPAHs) molecules represent an important class of organic materials with outstanding hole transport ability, because these molecules are inclined to form columnar stacks.[16,17] Dibenzo[g,p]chrysenes are a unique class of discotic-type

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DPAHs with a characteristic helical structure.[18-23] Due to their interesting photophysical and electronic properties such as good hole mobilities,[24,25] high quantum yields and long excited states lifetime,[26] dibenzo[g,p]chrysenes derivatives were applied in some organic electronic

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devices, such as organic thin-film transistors (OTFTs) as hole transporting materials[24] and organic light-emitting diodes (OLEDs) as emissive materials.[27] It is well-known that DPAHs can be applied as fluorescent emitters since they are generally featured with high thermal stabilities, high quantum efficiency of photoluminescence and high charge carrier mobilities. However, the exploration of DPAHs as host materials for OLEDs has been rarely reported. Very recently, J. N. Moorthy, et al., reported three novel anthracene derivatives as hosts for sky-blue and green OLEDs.[28] So far, dibenzo[g,p]chrysenes have been successfully synthesized via the following methods: (i) intramolecular

oxidative

carbon−carbon

coupling

reactions

(starting

from

9,10-diarylphenanthrenes,[29,30] 1,2-bis(biaryl-2-yl)ethynes,[26] or 9-(biaryl-2-yl)-phenanthrenes[31]); (ii)

Pd-catalyzed

intramolecular

dehydrohalogenation

reactions

(starting

from

2

ACCEPTED MANUSCRIPT 9-(biaryl-2-yl)-10-iodophenanthrenes[32] or (E)-1,2-diaryl-1,2-bis(2-bromoaryl)ethenes[33]); (iii) Pd-catalyzed

intermolecular

2,2′-dibromobiaryls[34] Friedel−Crafts

or

type

cross-coupling phenanthrenes

cyclization

reactions

with

(superacid-

or

(9,10-diborylphenanthrenes

dibenzosiloles[35]); TiF4-mediated

(iv)

domino

with

intramolecular cyclization

of

1,1-di(biphenyl-2-yl)-1,1-difluoroethenes).[36] However, most of these methods were generally hampered by lengthy synthetic procedures from starting materials to the target molecular

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frameworks. In this contribution, an alternative strategy was used for the preparation of dibenzo[g,p]chrysene derivatives. Fluorenone was used as the starting material, and the reductive coupling with Zn/ZnCl2 in THF/H2O gave the corresponding pinacol,[37] which was used in the next step without any purification. The subsequent acid-catalyzed rearrangement/cyclization afforded the

reaction

of

the

tetrabromide

with

phenylboronic

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dibenzo[g,p]chrysene framework in good yield. Then Pd-catalyzed Suzuki−Miyaura coupling acid

finished

the

synthesis

of

3,6,11,14-tetraphenyldibenzo[g,p]chrysene (TPDBC). The thermal stability, basic photophysical

thermal

stabilities

and

suitable

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properties and electrochemical behavior of TPDBC were fully studied, and it exhibited excellent triplet

energy

for

red

PHOLEDs.

Therefore,

a

bis(2-methyldibenzo-[f,h]-quinoxaline) Ir(III) (acetylacetonate) (Ir(MDQ)2(acac)) based red device was fabricated with a maximum external quantum efficiency of 14.4%. To the best of our knowledge, this study represented the first report with a dibenzo[g,p]chrysene derivative as host for a PHOLED, and the result suggested that dibenzo[g,p]chrysene could be a promising building

2. Experimental

1

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2.1. Experimental Section

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block for the construction of host materials.

H NMR and

13

C NMR spectra were recorded on a Bruker 400 instrument at room

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temperature. Mass spectra were recorded on a Thermo ISQ mass spectrometer using a direct exposure probe. UV-vis absorption spectra were recorded on a Perkin Elmer Lambda 750 spectrophotometer. PL spectra and phosphorescent spectra were recorded on a Hitachi F-4600 fluorescence spectrophotometer. Differential scanning calorimetry (DSC) was performed on a TA DSC 2010 unit at a heating rate of 10 oC min-1 under nitrogen. The glass transition temperatures (Tg) were determined from the second heating scan. Thermogravimetric analysis (TGA) was performed on a TA SDT 2960 instrument at a heating rate of 10 oC min-1 under nitrogen. Temperature at 5% weight loss was used as the decomposition temperature (Td). Cyclic voltammetry (CV) was carried out on a CHI600 voltammetric analyzer at room temperature with ferrocenium-ferrocene (Fc+/Fc) as the internal standard. Deaerated DMF was used as solvent for oxidation scan with tetrabutylammonium hexafluorophosphate (TBAPF6) (0.1 M) as the supporting electrolyte. A conventional three-electrode configuration consisting of a Pt-wire 3

ACCEPTED MANUSCRIPT counter electrode, an Ag/AgCl reference electrode, and a platinum working electrode was used. The cyclic voltammograms were obtained at a scan rate of 0.1 V s-1.

2.2. Device fabrication and measurement

The OLEDs were fabricated on the indium-tin oxide (ITO) coated transparent glass substrates,

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the ITO conductive layer having a thickness of ca. 100 nm and a sheet resistance of ca. 30 Ω per-square. The substrates were cleaned with ethanol, acetone and deionized water, and then dried in an oven, finally exposed to UV ozone for 30 min. All of the organic materials and metal layers under a vacuum of ca. 10-6 Torr. Four identical OLED devices were formed on each of the substrates and the emission area of 0.09 cm2 for each unit. The EL performances of the devices

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were measured with a PHOTO RESEARCH SpectraScan PR 655 PHOTOMETER and a

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KEITHLEY 2400 SourceMeter constant current source at room temperature.

2.3 Synthesis of material

All reactions were performed under argon atmosphere unless otherwise stated. 9H-Fluoren -9-one, bromine, phenylboronic acid, Zn powder and anhydrous zinc chloride were commercially available and were used without further purification. THF was purified by PURE SOLV

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(Innovative Technology) purification system.

3,6,11,14-Tetrabromodibenzo[g,p]chrysene (1): A mixture of 2,7-dibromo-9H-fluoren-9-one,[38] (1.64 g, 5 mmol), zinc powder (6.0 g, 91 mmol), ZnCl2 (1.2 g, 9 mmol) and 50% aqueous THF

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(10 mL) was stirred at room temperature for 3 h. The reaction mixture was combined with 3 N HCl (5 mL) and filtered to remove the Zn powder. The filtrate was extracted with toluene (3×50 mL), washed with water (3×50 mL), brine (3×50 mL), dried over anhydrous magnesium sulfate

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and filtered. Evaporation of the solvent in vacuo afforded crude pinacol which was used in the next step without further purification.

The foregoing pincaol was dissolved in AcOH (50 mL) and c.HCl (5 mL) and the mixture was reaction overnight at 110 oC. The reaction mixture was cooled to room temperature, filtered and washed with absolute ethyl alcohol, dichloromethane, and then dried under vacuum to give 1 as orange-yellow powder (1.1 g, ~53%). mp > 450 °C (dec). IR (KBr): v 2959, 2864, 1489, 1467, 1233, 1164, 793 cm-1. 1H NMR (400 MHz, DMSO-d6, 100 oC): δ = 8.61 (d, J = 8.3 Hz, 4H), 8.50 (s, 4H), 7.48 (d, J = 8.3 Hz, 4H) ppm. The orange solid was very slightly soluble in the common organic solvents, 13C NMR was therefore impractical. MS m/z: 643.72. Anal. Calcd for C26H12Br4 (%): C 48.49, H 1.88; found: C 48.57, H 1.75.

4

ACCEPTED MANUSCRIPT 3,6,11,14-Tetraphenyldibenzo[g,p]chrysene (TPDBC): 1 (2.9 g, 4.5 mmol), phenylboronic acid (3.3 g, 27 mmol) and Pd(PPh3)4 (0.4 g, 0.36 mmol) were dissolved in THF (100 mL) under argon, and then 2 M K2CO3 (25 mL, THF/Water = 4/1, v/v) was added. The resulting solution was heated at 70 oC for 36 h. After the reaction solution cooled to room temperature, put it into 200 mL water, and extracted with dichloromethane for 3 times. The organic layer was collected and evaporated. crude

product

was

purified

by

column

chromatography

using

petroleum

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The

ether/dichloromethane (2/1, v/v) to afford TPDBC as orange-yellow powder (2.5 g, 90%). mp 316 o

C (DSC result). IR (KBr): v 3052, 3029, 1603, 1480, 1394, 889, 825, 761, 680, 523 cm-1. 1H

NMR (400 MHz, CDCl3): δ = 8.89 (s, 4H), 8.65 (d, J = 8.5 Hz, 4H), 7.84 (d, J = 8.4 Hz, 4H), 7.68 (d, J = 7.5 Hz, 8H), 7.42 (t, J = 7.4 Hz, 8H), 7.36 (m, 4H) ppm. 13C NMR (151 MHz, CDCl3): δ =

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141.00, 139.14, 129.68, 129.46, 128.80, 128.31, 127.34, 125.64, 124.08 ppm. MS (m/z): [M]+

3. Results and discussion

3.1. Synthesis and characterization

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632.78; found: 632.41. Anal. Calcd for C50H32 (%): C 94.90, H 5.10; found: C 94.95, H 5.02.

The synthetic route to TPDBC is outlined in Scheme 1. The molecular structure of TPDBC was fully characterized with 1H/13C NMR spectroscopy (Supporting Information) and mass

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spectrometry. In order to further confirm the structure of TPDBC, a colorless single crystal was prepared by slow diffusion of ethanol into a chloroform solution and subjected to X-ray diffraction

analysis. The crystal structure is shown in Fig. 1 (CCDC number 1535712). The four phenyl groups in each quaterphenyl motif are positioned linearly. Due to the steric hindrance between the

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neighboring hydrogen atoms, the dihedral angle between these two quaterphenyl motifs is about 31.2º. So the rigid structure dibenzo[g,p]chrysene motif is highly twisted.

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3.2. Thermal stability

The thermal properties of TPDBC were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) at a scanning rate of 10 oC min-1 in a nitrogen atmosphere, and the experimental results are shown in Fig. 2 and the detailed data are summarized in Table 1. The experimental results showed that TPDBC exhibited good thermal and morphological stabilities with high decomposition temperature (Td, corresponding to 5% weight loss) and high glass transition temperature (Tg). As shown in Figure 2, the data of Td and Tg of TPDBC was 456 o

C and 159 oC, respectively. In addition, the crystallization temperature (Tc) and the melting point

(Tm, Fig S3) were also measured at 212 oC and 316 oC, respectively. It is worth noting that the thermodynamic properties of TPDBC is much better than the typical host materials, such as mCP

5

ACCEPTED MANUSCRIPT (1,3-bis(N-carbazolyl)benzene) or CBP (4,4'-bis(carbazol-9-yl)biphenyl),[39,40] which indicates that TPDBC could be applied as potential host material for PHOLEDs.

3.3. Photophysical properties

Room temperature UV-vis absorption and photoluminescence (PL) spectra in toluene solution low

temperature

(77

K)

phosphorescence

(Phos)

spectrum

in

a

frozen

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and

2-methyltetrahydrofuran matrix of TPDBC are show in Fig. 3 and the spectral data are summarized in Table 1. As shown by the UV-vis absorption curve, the maximum absorption is around 316 nm and the optic band gap (Eg) is calculated (3.25 eV) from the absorption onset. Upon excitation TPDBC showed intense emission with a peak at 423 nm. The Phos spectrum of

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TPDBC exhibited a structureless spectrum, and the highest vibronic band peaked at 588 nm, corresponding to the triplet energy (ET) of 2.11 eV. Since the ET is relative lower than the general

3.4. Electrochemical properties

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blue or green phosphors, TPDBC could be a suitable host for red PHOLEDs.

The electrochemical behavior of TPDBC in N,N-dimethyl formamide (DMF) solution was measured by cyclic voltammetry (CV). Using typically tri-electrode configuration method with ferrocene (Fc/Fc+) as the internal standard and with n-Bu4NPF6 as the supporting electrolyte. As

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shown in Fig. 4, the HOMO of TPDBC was calculated (-5.71 eV) from the onset of the first oxidation wave,[41] and the corresponding LUMO (-2.46 eV) was determined from the difference between Eg and the HOMO.

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3.5. Electroluminescent properties

In order to investigate the potential of TPDBC as the host material, a red PHOLED was

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fabricated with a conventional device configuration: ITO/HAT-CN (10 nm)/TAPC (45 nm)/TCTA (10 nm)/Host: 6 wt% Ir(MDQ)2(acac) (20 nm)/TmPyPB (45 nm)/Liq (2 nm)/Al (120 nm). The device data are summarized in Table 2. As shown by the current density–voltage–luminance (J–V–L) characteristics (Fig. 5a), the operating voltage at 100 cd m-2 is 3.6 V for TPDBC based device. The device achieved decent performance and the maximum CE, PE, and EQE reached 17.0 cd A-1, 15.9 lm W-1, and 14.4%, respectively. The device exhibited typical Commission Internationale de L’Eclairage (CIE) coordinates (0.61, 0.39) of Ir(MDQ)2(acac) (Fig. 5c), which indicated the efficient energy transfer from TPDBC to the dopant.[42-45]

3.6. Charge carrier transport properties

6

ACCEPTED MANUSCRIPT In order to investigate the hole and electron-transporting properties of the host TPDBC, the hole- and electron-only devices with the configuration of ITO/MoO3 (10 nm)/TPDBC (100 nm)/MoO3 (10 nm)/Al (100 nm) and ITO/TmPyPB (20 nm)/TPDBC (100 nm)/ TmPyPB (20 nm)/Liq (2 nm)/Al (100 nm) were fabricated, respectively. The current density versus voltage (J-V) characteristics of the hole- and electron-only devices were compiled in Fig. 6. Since there is no electron-withdrawing group attached to the backbone of TPDBC, it is not surprising that

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TPDBC demonstrated relatively low electron mobility as compared to its hole mobility.

4. Conclusion

In conclusion, a novel dibenzo[g,p]chrysene framework host material TPDBC was designed

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and synthesized. The material showed excellent thermal stability and suitable ET and frontier orbital energy levels. As a result, red PHOLED was fabricated with TPDBC as host material. The device exhibited decent electroluminescence with the maximum CE, PE, and EQE of 17.0 cd A-1,

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15.9 lm W-1, and 14.4%, respectively. The results indicate that the dibenzo[g,p]chrysene derivatives have a great potential to construct novel host materials for highly efficient OLEDs.

Acknowledgements

We thank to the financial support from the National Key R&D Program of China

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(2016YFB0400703), the National Natural Science Foundation of China (61307036, 21472135) and Natural Science Foundation of Jiangsu Province of China (BK20151216). This project is also funded by Collaborative Innovation Center of Suzhou Nano Science and Technology (CIC-Nano), Soochow University and by the Priority Academic Program Development of Jiangsu Higher

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ACCEPTED MANUSCRIPT 2015;17:4984−7. [37] Debroy, P, Lindeman, S, V, Rathore, R. Hexabenzo[4.4.4]propellane: A Helical Molecular Platform for the Construction of Electroactive Materials. Org. Lett. 2007;9:4091−4. [38] Wang, P-H, Ho, M-S, Yang, S-H, Chen, K-B, Hsu. C-S. Synthesis of thermal-stable and photo-crosslinkable polyfluorenes for the applications of polymer light-emitting diodes. J. Polym. Sci. Part A: Polym. Chem. 2010;48:516−24.

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[39] Tsai, M-H, Hong, Y-H, Chang, C-H, Su, H-C, Wu, C-C, Matoliukstyte, A, et al. 3-(9-Carbazolyl)carbazoles and 3,6-Di(9-carbazolyl)carbazoles as Effective Host Materials for Efficient Blue Organic Electrophosphorescence. Adv. Mater. 2007;19:862−6.

[40] Yeh, S-J, Wu, M-F, Chen, C-T, Song, Y-H, Chi, Y, Ho, M-H, et al. New dopant and host materials for

Blue-Light-Emitting

phosphorescent

organic

electroluminescent

Adv.

Mater.

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2005;17:285-9.

devices.

[41] The HOMO energy was determined from the onsets of the first oxidation and potential as EHOMO = [-4.8 - Eonset vs. Fc/Fc+] eV. In this paper, we used -4.8 eV as the potential below vacuum level of

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ferrocene, which appears most often in the literature.

[42] Duan, J, P, Sun, P, P, Cheng, C, H. New iridium complexes as highly efficient orange-red emitters in organic light-emitting diodes. Adv. Mater. 2003;15:224-8.

[43] Han, C, Zhu, L, Li, J, Zhao, F, Zhang, Z, Xu, H, et al. Highly efficient multifluorenyl host materials with unsymmetrical molecular configurations and localized triplet states for green and red phosphorescent devices. Adv. Mater. 2014;26:7070-7.

[44] Liu, X-Y, Liang, F, Yuan, Y, Cui, L-S, Jiang, Z,-Q, Liao, L-S. An effective host material with

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thermally activated delayed fluorescence formed by confined conjugation for red phosphorescent organic light-emitting diodes. Chem. Commun. 2016;52:8149-51. [45] Liu, X-Y, Liang, F, Yuan, Y, Jiang, Z,-Q, Liao, L-S. Utilizing 9,10-dihydroacridine and pyrazine-containing donor–acceptor host materials for highly efficient red phosphorescent organic

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light-emitting diodes. J. Mater. Chem. C. 2016;4:7869-74.

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ACCEPTED MANUSCRIPT Figure Captions: Scheme 1. Synthetic routes to TPDBC. Fig. 1. Crystal structure of TPDBC. Fig. 2. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC, inset) curves of TPDBC. Fig. 3. UV-vis absorption, PL and Phos spectra of TPDBC. Fig. 4. Cyclic voltammograms of and TPDBC. Fig. 5. (a) J–V–L characteristics; (b) CE–, PE–, and EQE–L curves, and (c) EL spectrum of red PHOLED.

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Fig. 6 J-V characteristic curves of single-carrier-transporting devices based on TPDBC.

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Fig. 1. Crystal structure of TPDBC.

Table 1. Physical properties of TPDBC.

PL λmax a)

ΦPb)

Tg c)/Tc d)/ Tm e)/ Td f)

Eg g)

ET h)

HOMO i)

LUMO j)

[nm]

[nm]

[%]

[oC]

[eV]

[eV]

[eV]

[eV]

316

423

32.6

159/212/316/456

3.25

2.11

-5.71

-2.46

Compound

TPDBC

Measured in toluene solution at room temperature. b) ΦP: Quantum yield measured in DCM solution with

an integrating sphere. point.

f)

onset.

h)

c)

Tg: Glass transition temperature.

Td: Decomposition temperature.

g)

d)

Tc: Crystallization temperature.

ET: Measured in 2-MeTHF glass matrix at 77 K. j)

e)

Tm: Melting

Eg: Band gaps, calculated from the corresponding absorption

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a)

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Abs λmax a)

i)

HOMO levels, calculated from cyclic

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voltammetry (CV) data. LUMO level, calculated from the HOMO and corresponding Eg.

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ACCEPTED MANUSCRIPT Table 2. Electroluminescence characteristics of the device.

TPDBC a)

ηCE b)

ηPE b)

ηext c)

CIE d)

[V]

[cd A-1]

[lm W-1]

[%]

[x, y]

3.6

17.0, 14.2, 12.9

15.9, 11.0, 9.2

Dopant

Ir(MDQ)2(acac) -2 b)

Voltages at 100 cd m .

-2

0.61, 0.39 -2 c)

Efficiencies in the order of the maxima, at 100 cd m and at 1000 cd m . d)

Maximum

-2

Commission International de Ieelaiage coordinates measured at 5 mA cm .

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external quantum efficiency.

14.4

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Host

V a)

Scheme 1. Synthetic route to TPDBC.

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Fig. 2. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC, inset) curves of TPDBC.

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Fig. 3. UV-vis absorption, PL and Phos spectra of TPDBC.

Fig. 4. Cyclic voltammograms of and TPDBC.

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Fig. 5. (a) J–V–L characteristics; (b) CE–, PE–, and EQE–L curves, and (c) EL spectrum of red PHOLED.

Fig. 6 J-V characteristic curves of single-carrier-transporting devices based on TPDBC.

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ACCEPTED MANUSCRIPT A simplified synthetic route for one polycyclic aromatic hydrocarbon (BPAH) compound, dibenzo[g,p]chrysene, was developed. It was the first report using dibenzo[g,p]chrysene derivative as red OLED host material with external quantum efficiency of 14.4%. The device results suggest that BPAHs molecular platform has great potential in

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