WO2023104285A1 - Boron doped polycyclic aromatic hydrocarbon emitting compound (b-pah) and method of synthesizing b-pah - Google Patents

Abstract

A boron doped polycyclic aromatic hydrocarbon (B-PAH) compound includes a boron-dopeddibenzophenalenyl unit, and one or more aromatic nitrogen-doped donor units that are arrangedon a periphery of the boron-doped dibenzophenalenyl unit. The B-PAH compound is beneficialto generate highly efficient and stable blue emitting devices such as for use in an organic light-emitting diode (OLED) display.

Description

BORON DOPED POLYCYCLIC AROMATIC HYDROCARBON EMITTING

COMPOUND (B-PAH) AND METHOD OF SYNTHESIZING B-PAH

TECHNICAL FIELD

The present disclosure relates generally to the field of display technology and more specifically, to boron doped polycyclic aromatic hydrocarbon emitting compound, and a method of synthesizing boron doped polycyclic aromatic hydrocarbon emitting compound.

BACKGROUND

The rapid development of the display technology in the recent years, lead to a wide use of advanced display screens in electronic consumer goods. Display screens play a crucial role in the customer experience of a product. Currently, display based on organic light-emitting diode (OLED) technology are the best performing products on the market, thanks to their infinite contrast ratio, wide colour gamut, flexibility, and variety of form factors. However, the overall brightness of OLED displays, which must obey to constraints inferred by the commercial device lifetime requirements, can still be improved.

An OLED display screen does not require a backlight like in the liquid crystal (LC) display technology. Therefore, OLED displays are much thinner and lightweight compared to LC displays which is a relevant advantage for their inclusion in consumer products. The absence of back-light allows to achieve the true black and thus infinite contrast ratio giving to the user the perception of more vivid colours. The core of this class of display screen are the microscopic OLED devices, included in each pixel, and emitting the three fundamental colours. Each of this devices can embed more than 20 functional layers. In a simpler configuration, an OLED device consists of a stacked structure (constituted of a hole-injection layer, hole transport layer, a lightemitting layer, an electron transport layer, and an electron-injection layer) sandwiched between anode and cathode electrodes (one of which is semitransparent to allow light extraction). Charge carriers (holes and electrons) are injected in the device via the electrodes (anode and cathode, respectively) and transported through the functional layer under the action of the electric field applied. Opposite charge carries recombine in the emissive layer forming excited states (excitons) which are able to relax via a radiative recombination with the emission of a photon, thus generating light emission. One of the main factors influencing the efficiency of the light generation process is related to the type of emissive material. In fluorescent materials the radiative recombination is allowed only from singlet exciton states, leading to a maximum internal quantum efficiency, for electrically generated excitons, of only 25%. Differently in phosphorescent materials, able to undergo radiative recombination from triplet states, the internal quantum efficiency can reach 100%. Commercially available OLED displays includes phosphorescent green and red-emitting materials, which can deliver high device efficiency and lifetime sufficient for commercial applications. However, blue phosphorescent materials are not suitable for commercial applications due to their reduce stability compared to the red and green counterparts. Indeed, due to the accumulation of highly energetic triplet states in the emissive layer, such emitters exhibit rapid degradation. As a result, blue-fluorescent emitters are less efficient but more stable than their phosphorescent counterparts, are introduced as a replacement of the phosphorescent materials. However, the conventional fluorescent blueemitters can convert only part of the total excitations generated in the emissive layer. Further, complex (or low yield) synthetic routes of the conventional fluorescent blue-emitters further increases production costs of OLED displays. Moreover, full width half maximum of conventional fluorescent blue-emitters are larger than 50 nm reducing the colour gamut achievable for an OLED display. The reduced stability and internal quantum efficiency of the blue-fluorescent emitters, compared to the red and green phosphorescent counterparts, negatively affects the OLED display performance. Indeed, lower maximum brightness is achievable (compared to LC display), to preserve the OLED device lifetime. Additionally, the lower efficiency of blue-emitting devices increase the overall display power consumption. As a result, there exists a technical problem of how to improve the efficiency of the fluorescent blue-emitters for commercial applications, such as for use in the OLED display screen.

Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with the conventional fluorescent blue-emitters. SUMMARY

The present disclosure provides a boron doped polycyclic aromatic hydrocarbon emitting compound and a method of synthesizing the boron doped polycyclic aromatic hydrocarbon. The present disclosure provides a solution to the existing problem of how to improve the efficiency of the conventional fluorescent blue-emitters. An objective of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in the prior art and provides an improved emitting compound, such as the boron doped polycyclic aromatic hydrocarbon emitting compound and the method of synthesizing the boron doped polycyclic aromatic hydrocarbon with improved optical performance for use in an organic light-emitting diode (OLED) displays.

One or more objectives of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.

In one aspect, the present disclosure provides a boron doped polycyclic aromatic hydrocarbon, B-PAH. The boron doped polycyclic aromatic hydrocarbon, B-PAH comprises, a boron-doped dibenzophenalenyl unit. The boron doped polycyclic aromatic hydrocarbon, B-PAH further comprises one or more aromatic nitrogen-doped donor units arranged on a periphery of the dibenzophenalenyl unit.

The B-PAH compound includes one or more aromatic nitrogen-doped donor units that are arranged on the periphery of the boron-doped dibenzophenalenyl unit, which could result in delayed fluorescence. Moreover, an internal quantum yield of the B-PAH compound is also improved. The B-PAH compound further shows improved thermal stability, which is a positive prerequisite for the stability of the OLED display. Moreover, an overall optical performance of the B-PAH compound (full width half maximum of the emission (FWHM) and photoluminescence quantum yield (PLQY)) is also improved due to the arrangement of the one or more aromatic nitrogen-doped donor units on the periphery of the boron-doped dibenzophenalenyl unit. As a result, the B-PAH compound is beneficial to generate highly efficient and stable blue emitting devices such as for use in OLED displays.

In a further implementation form, the B-PAH compound is configured to perform thermally activated delayed fluorescence. The thermally activated delayed fluorescence helps in converting the triplet states into singlet ones and overcome the efficiency limitations imposed by the selection rules and generate highly efficient and stable blue emitting OLED display screen.

In another aspect, the present disclosure further provides an organic light-emitting diode (OLED) display, comprising the B-PAH compound.

The OLED display achieves all the advantages and technical effects of the B-PAH compound of the present disclosure.

In another aspect, a method of synthesizing a boron doped polycyclic aromatic hydrocarbon, B-PAH, compound, comprises mixing a substituted diarylalkyne compound and 2,4,6-tri-tert- butylpyridine, TBP, in a reaction vessel. Further, adding anhydrous 1,2,4-trichlorobenzene, TCB, and boron tribromide, BBr3. Further, heating the mixture above a threshold temperature and stirring for at least a predetermined period of time. After that, cool to room temperature and add a Grignard reagent, RMgBr.

The method achieves all the advantages and technical effects of the B-PAH compound of the present disclosure.

It has to be noted that all devices, elements, circuitry, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims. Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

FIG. 1 is an illustration of a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure;

FIG. 2 is an illustration that depicts steps of preparing a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure;

FIG. 3A is an illustration that depicts steps of fusion of one or more aromatic nitrogen- doped donor units to a boron-doped dibenzophenal enyl unit, in accordance with an embodiment of the present disclosure;

FIG. 3B is another illustration that depicts steps of fusion of one or more aromatic nitrogen-doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with another embodiment of the present disclosure, in accordance with an embodiment of the present disclosure;

FIG. 3C is another illustration that depicts steps of fusion of one or more aromatic nitrogen-doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with yet another embodiment of the present disclosure, in accordance with an embodiment of the present disclosure;

FIG. 3D is another illustration that depicts steps of fusion of one or more aromatic nitrogen-doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with another embodiment of the present disclosure, in accordance with an embodiment of the present disclosure;

FIG. 3E is an illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with yet another embodiment of the present disclosure;

FIG. 3F is another illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with another embodiment of the present disclosure;

FIG. 3G is an illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with another embodiment of the present disclosure;

FIG. 3H is yet another illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with yet another embodiment of the present disclosure;

FIG. 31 is another illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with another embodiment of the present disclosure;

FIG. 4 is a graphical representation that depicts relation between wavelength and intensity for a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure;

FIG. 5 is a block diagram of an organic light-emitting diode (OLED) display, in accordance with an embodiment of the present disclosure; and

FIG. 6 is a flow chart of a method of synthesizing a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure.

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the nonunderlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing. DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.

FIG. 1 is an illustration of a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound 100. The B-PAH compound 100 includes a boron-doped dibenzophenalenyl unit 102 and one or more aromatic nitrogen-doped donor units 104. The dotted boxes shown in FIG. 1 are for representation purposes only.

In one aspect, there is provided the boron doped polycyclic aromatic hydrocarbon (B-PAH) compound 100. The boron doped polycyclic aromatic hydrocarbon (B-PAH) compound 100 includes the boron-doped dibenzophenalenyl unit 102 and the one or more aromatic nitrogen- doped donor units 104 that are arranged on a periphery of the boron-doped dibenzophenalenyl unit 102. In an implementation, each unit from the one or more aromatic nitrogen-doped donor units 104 acts as a donor unit (i.e., electron-rich), and the boron-doped dibenzophenalenyl unit 102 acts as an acceptor unit (i.e., electron deficient). In an example, the one or more aromatic nitrogen-doped donor units 104 are fused in a controlled manner on the periphery of the boron- doped dibenzophenalenyl unit 102, which results in the formation of the B-PAH compound 100. The donor and the acceptor units further generate a favorable energetic scenario for the occurrence of the delayed fluorescence in the B-PAH compound 100. Further, an internal quantum yield of the B-PAH compound 100 is improved due to the arrangement of the one or more aromatic nitrogen-doped donor units 104 on the periphery of the boron-doped dibenzophenalenyl unit 102. The B-PAH compound 100 further shows thermal stability above 300 C, which is a positive prerequisite for the stability of the OLED device. As a result, the B- PAH compound 100 is beneficial to generate highly efficient and stable blue-emitting devices such as for use in the OLED display. In an implementation, the B-PAH compound 100 is synthesized via a one-pot synthetic route, which allows a favorable approach toward the material mass production of the B-PAH compound 100. In another implementation, the B-PAH compound 100 (or multifunctional boron and nitrogen doped-polycyclic aromatic hydrocarbons) contains different donor substituents, such as carbazole, 9,9-dimethyl-9,10- dihydroacridine or lOH-phenoxazine, and the like. Moreover, the synthetic route which allows the synthesis of the B-PAH compound 100 in one pote reaction is performed in a scalable manner. In an example, a range of additional structures is also suggested to further improve the performance of the B-PAH compound 100, as further shown and described in FIGs. 3 A to 31.

In an implementation, an optical emission of the B-PAH compound 100 is shifted toward deeper blue emission (e.g., peaked at 445 nanometres), with an improved photoluminescence quantum yield (PLQY), such as around 96%. Beneficially, as compared to the conventional approach, full-width half maxima (FWMH) of the B-PAH compound 100 is also improved (e.g., narrower emission of below 50 nanometres). Moreover, the overall optical performance of the B-PAH compound 100 is also improved due to the arrangement of the one or more aromatic nitrogen- doped donor units 104 on the periphery of the boron-doped dibenzophenalenyl unit 102.

In accordance with an embodiment, the B-PAH compound 100 is configured to perform thermally activated delayed fluorescence. In an implementation, the B-PAH compound 100 exploits different types of delayed fluorescence, specifically triplet-triplet fusion (TTF) to generate an emissive singlet state. Therefore, the B-PAH compound 100 is configured to perform (or exploit) the thermally activated delayed fluorescence (TADF) to convert triplete states into singlet ones and also to overcome the efficiency limitations of the conventional approaches.

The B-PAH compound 100 includes the one or more aromatic nitrogen-doped donor units 104 that are arranged on the periphery of the boron-doped dibenzophenalenyl unit 102, which results in delayed fluorescence. Moreover, an internal quantum yield of the B-PAH compound 100 is also improved. The B-PAH compound 100 further shows improved thermal stability, which is a positive prerequisite for the stability of the OLED display. Moreover, the overall optical performance of the B-PAH compound 100 is also improved due to the presence of the one or more aromatic nitrogen-doped donor units 104 that are arranged on the periphery of the boron-doped dibenzophenalenyl unit 102. As a result, the B-PAH compound 100 is beneficial to generate highly efficient and stable blue emitting devices such as for use in the OLED display.

FIG. 2 an illustration that depicts steps of preparing a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure. FIG. 2 is described in conjunction with elements from the FIG. 1. With reference to FIG. 2, there are shown various steps of preparing a B-PAH compound 200 (or the B-PAH compound 100 of FIG.1). With reference to the FIG. 2, at step 202 a substituted diarylalkyne is used firstly. The substituted diarylalkyne includes three benzene groups (e.g., a, b, and c), and alkyl group (Rn) that are attached to each benzene group (e.g., via after breaking a bond). Thereafter, the substituted diaiylalkyne is processed by heating for a particular time period, and under the presence of boron tribromide (BBrft, 2,4,6-tri-tert-butylpyridine (TBP), and trichlorobenzene (TCB). In an example, the substituted diarylalkyne is heated at 200 degrees Celsius for 12 hours. After that, the substituted diarylalkyne is processed with a combination of argon (Ag), magnesium (Mg), and bromide (Br) (e.g., for one hour).

In an implementation, the substituted diarylalkyne is processed using standard vacuum-line and Schlenk techniques to prepare the B-PAH compound 200. Firstly, the substituted diarylalkyne compound (e.g., 1.0 equiv), 2,4,6-tri-tert-butylpyridine (TBP) (1.5 equiv) are loaded in a twonecked schlenk flask, and under the protection of argon. After that, anhydrous 1,2,4- trichlorobenzene (TCB) (e.g., one milliliter/millimole (mL/mmol)), and boron tribromide (BBr3) (e.g., 3.0 equiv) is added. Thereafter, a resulted mixture is heated to 200 °C and stirred for 12 hours. The resulted mixture is further cooled down at room temperature, and Grignard reagents (RMgBr) (e.g., 4.0 equiv.) are used for work-up, which is further stirred for one hour. After that, all volatiles are removed under reduced pressure, and a crude product is purified (e g., by flash chromatography on silica gel) to get the B-PAH compound 200.

At step 204, the B-PAH compound 200 is obtained. The B-PAH compound 200 includes the boron-doped dibenzophenalenyl unit 102, and the one or more aromatic nitrogen-doped donor units 104 (e.g., shown by d in FIG. 2) that are arranged on a periphery of the boron-doped dibenzophenalenyl unit 102.

FIG. 3A is an illustration that depicts steps of fusion of one or more aromatic nitrogen-doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3A is described in conjunction with elements from the FIGs. 1, and FIG. 2. With reference to FIG. 3A, there are shown various steps to achieve the fusion of one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN-5.

With reference to the FIG. 3 A, at step 302A, a structure la is added with structure 2a. In an example, the structure la corresponds to substituted diarylalkyne compounds. Thereafter, mixture of the structures la and 2a is heated (e.g., up to 150 degree Celsius) in the presence of caesium carbonate (CS2CO3) and dimethylformamide (DMF). In an example, the DMF corresponds to a solvent with a low evaporation rate.

In accordance with an embodiment, at least one of the donor units is substituted for a hydrogen atom in the structure 2a. For example, with reference to FIG 3 A, at step 302 , the structure la is substituted for the hydrogen atom of the structure 2a.

At step 302B, a structure N-3a is obtained that is further processed with dimethylacetamide in the presence of potassium carbonate (K2CO3) and pd(pbu3)2. In an example, the structure N- 3a is processed for three hours.

At step 302C, a structure N-4a is obtained that is further processed with boron tribromide (BBn), 2,4,6-tri-tert-butylpyridine (TBP), trichlorobenzene (TCB), and a solution of Mesitylmagnesium bromide (MesMgBr). In an example, the structure N-4a is processed for two hours and at a temperature of two hundred degrees Celsius.

At step 302D, a structure BN-5 is obtained in which the aromatic nitrogen-doped donor units 104 are arranged at the periphery the boron-doped dibenzophenalenyl unit 102.

In an implementation, at least one of the donor units is fused to the boron-doped dibenzophenalenyl unit 102. For example, at step 302D, the structure BN-5 includes at least one of the donor unit that is fused to the boron-doped dibenzophenalenyl unit 102.

In another implementation, at least one of the donor units is a carbazole unit. For example, at least one unit from the one or more aromatic nitrogen-doped donor units 104 is the carbazole unit. In an example, the carbazole unit is fused to the boron-doped dibenzophenalenyl unit 102.

FIG. 3B is another illustration that depicts steps of fusion of one or more aromatic nitrogen- doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3B is described in conjunction with elements from the FIGs. 1, 2, and 3. With reference to FIG. 3B, there are shown various steps of fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN-6, where the aromatic nitrogen-doped donor units 104 is placed on the left side and the boron-doped dibenzophenalenyl unit 102 is placed on the right side. With reference to the FIG. 3B, at step 304A, a structure lb is added with the structure 2a (of FIG. 3A). In an example, the structure lb is basically substituted diarylalkyne compounds. Further, the mixture of the structures lb and 2a is heated (e.g., up to 150 degree Celsius) in the presence of Caesium carbonate (CS2CO3) and dimethylformamide (DMF). As disclosed above that the DMF is a solvent with a low evaporation rate.

At step 304B, a structure N-3b is obtained that is further processed with the dimethylacetamide (e g., for three hours) in the presence of potassium carbonate (K2CO3) and pd(pbu3)2.

At step 304C, a structure N-4b is obtained that is processed with boron tribromide (BBn), 2,4,6- tri-tert-butylpyridine (TBP), trichlorobenzene (TCB), and MesMgBr. In an example, the structure N-4b is processed for two hours and at a temperature of two hundred degree Celsius.

At step 304D, the structure BN-6 is obtained in which the aromatic nitrogen-doped donor units 104 are placed on the left side of the boron-doped dibenzophenalenyl unit 102.

FIG. 3C is another illustration that depicts steps of fusion of one or more aromatic nitrogen- doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3C is described in conjunction with elements from the FIGs. 1, 2, 3 A, and 3B. With reference to FIG. 3C, there are shown various steps of fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN-7.

With reference to the FIG. 3C at step 306A, a structure 1c is added with the structure 2a (of FIG. 3A). In an example, the structure 1c is basically substituted diarylalkyne compounds. Further, the mixture of structures 1c and 2a is heated (e.g., up to 150 degree Celsius) in the presence of caesium carbonate (CS2CO3) and dimethylformamide (DMF).

At step 306B, a structure N-3c is obtained that is further processed with the dimethylacetamide in the presence of potassium carbonate (K2CO3) and pd(pbu3)2. In an example, the structure N-3c is processed for three hours.

At step 306C, a structure N-4c is obtained that is processed with boron tribromide (BBn), 2,4,6- tri-tert-butylpyridine (TBP), trichlorobenzene (TCB), and MesMgBr. In an example, the structure N-4c is processed for two hours and at a temperature of two hundred degree Celsius. At step 306D, the structure BN-7 is obtained in which the aromatic nitrogen-doped donor units 104 are placed on the right side of the boron-doped dibenzophenalenyl unit 102.

FIG. 3D is another illustration that depicts steps of fusion of one or more aromatic nitrogen- doped donor units to a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3D is described in conjunction with elements from the FIGs. 1, 2, 3A, 3B and 3C. With reference to FIG. 3D, there are shown various steps of fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron- doped dibenzophenalenyl unit 102 results in the formation of a structure BN-8.

With reference to the FIG. 3D at step 308A, a structure Id is added with the structure 2a (of FIG.3A). In an example, the structure Id is basically substituted diarylalkyne compounds. Further, the mixture of structures Id and 2a is heated (e.g., up to 150 degree Celsius) in the presence of the caesium carbonate (CS2CO3) and the dimethylformamide (DMF).

At step 308B, a structure N-3d is obtained that is processed with the dimethylacetamide (e g., for three hours) in the presence of potassium carbonate (K2CO3) and pd(pbu3)2.

At step 308C, a structure N-4d is obtained that is processed with the boron tribromide (BB ), the 2,4,6-tri-tert-butylpyridine (TBP), the trichlorobenzene (TCB), and the MesMgBr. In an implementation, the structure N-4d is processed for two hours and at a temperature of two hundred degree Celsius.

At step 308D, the stmcture BN-8 is obtained in which the aromatic nitrogen-doped donor units 104 are placed on the left-bottom side of the Boron-doped dibenzophenalenyl unit 102.

FIG. 3E is an illustration that depicts steps of arrangement of one or more aromatic nitrogen- doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3E is described in conjunction with elements from the FIGs. 1, 2, 3A, 3B, 3C and 3D. With reference to FIG. 3E, there are shown various steps of arrangement of the one or more (or multiple) aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen- doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN-9. With reference to the FIG 3E at step 310A, a structure le is added with the structure 2a of FIG 3A. In an example, the structure le corresponds to substituted diarylalkyne compounds. Further, the mixture of structures le and 2a is heated (e.g., up to 150 degree Celsius) in the presence of the caesium carbonate (CS2CO3) and the dimethylformamide (DMF).

At step 310B, a structure N-3e is obtained, where the structure le is arranged between two structures (i.e., in between two structures 2a), as shown in FIG. 3E. The structure N-3e is further processed in three phases. Firstly, the processing is performed under the presence of n- Butyllithium (nBuLi) and trichlorobenzene (TCB) (e g., at zero degree Celsius for 0.5 hours). After that, a resulted structure is processed under the presence of boron tribromide (BBn), 2,4,6-tri-tert-butylpyridine (TBP). For example, at a temperature of two hundred degree Celsius for 12 hours. Finally, the resulted structure is further processed under the presence ofMesMgBr (e g., for two hours).

At step 310C, the structure BN-9 is obtained in which the boron-doped dibenzophenalenyl unit 102 is placed between two aromatic nitrogen-doped donor units 104.

FIG. 3F is another illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3F is described in conjunction with elements from the FIGs. 1, 2, 3 A, 3B, 3C, 3D and 3E. With reference to FIG. 3F, there are shown various steps of arrangement of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN- 10.

With reference to the FIG. 3F, at step 312A, a structure lb is added with the structure 2b of FIG. 3A. In an example, the structure lb corresponds to substituted diarylalkyne compounds. Further, the mixture of structure lb and 2b processed under the presence of sris (dibenzylideneacetone) dipalladium (0) (Pd(dba)2) and sodium tert-butoxide (NaOtBu). In an implementation, the (Pd(dba)2) is an organopalladium compound, which is a complex of palladium (0) with dibenzylideneacetone. Further the mixture of the structure lb and the structure 2b is heated (e g., up at 100 degree Celsius) in the presence of PtBm and PhMe.

At step 312B, a structure N-3f is obtained that is processed with the boron tribromide (BBn), the 2,4,6-tri-tert-butylpyridine (TBP), the trichlorobenzene (TCB), and the MesMgBr. In an implementation, the structure N-3f is processed for two hours and at a temperature of two hundred degree Celsius.

At step 312C, the structure BN- 10 is obtained. The structure BN- 10 includes a versatile donor or acceptor for tuning energy (AEST) of the structure BN- 10.

FIG. 3 G is an illustration that depicts steps of arrangement of one or more aromatic nitrogen- doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3G is described in conjunction with elements from the FIGs. 1, 2, 3A, 3B, 3C, 3D, 3E and 3F. With reference to FIG. 3G, there are shown various steps of arrangement of the one or more aromatic nitrogen-doped donor units 104 to the boron- doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN-11.

With reference to the FIG. 3G, at step 314A, the structure lb is added with a structure 2c. Further, the mixture of structures lb and 2c is processed under the presence of tris(dibenzylideneacetone)dipalladium (0) (Pd(dba)2), and todium tert-butoxide (NaOtBu). Further the mixture of the structures lb and 2c is heated (e.g., up at 100 degree Celsius) in the presence of PtBus and PhMe.

At step 314B, a structure N-3g is obtained that is processed with the boron tribromide (BBn), the 2,4,6-tri-tert-butylpyridine (TBP), the trichlorobenzene (TCB), and the MesMgBr. In an implementation, the structure N-3g is processed for two hours and at a temperature of two hundred degree Celsius.

At step 314C, the structure BN-11 is obtained. The structure BN-11 includes a versatile donor or acceptor for tuning energy (AEST) of the structure BN-11.

FIG. 3H is yet another illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 3H is described in conjunction with elements from the FIGs. 1, 2, 3A, 3B, 3C, 3D, 3E, 3F and 3G. With reference to FIG. 3H, there are shown various steps of arrangement of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen- doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN- 12.

With reference to the at step 316A, a structure is heated (e.g., up to 60 degree Celsius) in the presence of magnesium (Mg) and tetrahydrofuran (THF). The THF is an organic compound with the formula (CH2)4O. In an example, the organic compound is classified as heterocyclic compound.

At step 316B, a structure G-l is obtained. The structure G-l is doped with nitrogen. Further, magnesium and bromide are arranged at their periphery.

At step 316C, a structure Ih is processed. In an example, the structure Ih corresponds to substituted diarylalkyne compounds. Thereafter, the structure Ih is heated (e.g., at 200 degree Celsius) in the presence of the boron tribromide (BBn), the 2,4,6-tri-tert-butylpyridine (TBP), and the trichlorobenzene (TCB). After that, the structure Ih is processed with the structure G- 1. In an implementation, the structure Ih is processed with the structure G-l for two hours.

At step 316D, the structure BN 12 is obtained. The structure BN-12 includes a versatile donor or acceptor for tuning energy (AEST) of the structure BN- 12.

FIG. 31 is another illustration that depicts steps of arrangement of one or more aromatic nitrogen-doped donor units on a boron-doped dibenzophenalenyl unit, in accordance with an embodiment of the present disclosure. FIG. 31 is described in conjunction with elements from the FIGs. 1, 2, 3A, 3B, 3C, 3D, 3E, 3F, 3G and 3H. With reference to FIG. 31, there are shown various steps of arrangement of the one or more aromatic nitrogen-doped donor units 104 to the boron-doped dibenzophenalenyl unit 102. The fusion of the one or more aromatic nitrogen- doped donor units 104 to the boron-doped dibenzophenalenyl unit 102 results in the formation of a structure BN-13.

With reference to the FIG. 31, at step 318A, the structure lb of FIG. 3B is added with the structure 2b of FIG. 3A. Further, the mixture of the structure lb and the structure 2b is heated (e g., up to 150 degree Celsius) in the presence of the caesium carbonate (CS2CO3) and the dimethylformamide (DMF).

At step 318B, a structure N-3h is obtained, which is further processed. Firstly, the processing is performed under the presence of the boron tribromide (BBn), the 2,4,6-tri-tert-butylpyridine (TBP), and the trichlorobenzene (TCB). In an implementation, the processing is performed for half an hour and at a temperature of two hundred degree Celsius. Thereafter, the structure N- 3h is processed with structure G-2 (e.g., for two hours).

At step 318C, the structure BN- 13 is obtained. The structure BN- 13 includes a versatile donor or acceptor for tuning energy (AEST) of the structure BN-13.

FIG. 4 is a graphical representation that depicts relation between wavelength and intensity for a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure. FIG.4 is described in conjunction with elements from the FIGs. 1, 2, and 3 A to 31. With reference to FIG. 4, there is shown a graphical representation that includes an X-axis 402, and a Y-axis 404.

With reference to FIG. 4, the X-axis 402 represents wavelength (in nanometre), and the Y-axis represents corresponding intensity (in auxiliary units) of optical emission of the B-PAH compound 100. There is further shown that the optical emission of the B-PAH compound 100 is shifted toward deeper blue emission. In an example, the optical emission of the B-PAH compound 100 is shifted at 445 nanometres. In another example, the optical emission of the B- PAH compound 100 is shifted at 455 nanometres. There is further shown an improved photoluminescence quantum yield (PLQY) around of 96%, as compared to the conventional emitters. Moreover, the full width half maxima (FWMH) of the B-PAH compound 100 is also having a value of less than 50 (i.e., a narrower emission of below 50), which is again comparatively improved. Beneficially as compared to the conventional emitters, overall optical performance of the B-PAH compound 100 due to the presence of the one or more aromatic nitrogen-doped donor units 104 that are arranged on the periphery of the boron-doped dibenzophenalenyl unit 102.

FIG. 5 is a block diagram of an organic light-emitting diode (OLED) display, in accordance with an embodiment of the present disclosure. FIG. 5 is described in conjunction with elements from the FIGs. 1, 2, 3 A to 31, and 4. With reference to the FIG. 5, there is shown a block diagram 500 of an organic light-emitting diode (OLED) display that includes the B-PAH compound 100.

In another aspect, the OLED display 502 includes the B-PAH compound 100 (or the B-PAH compound 200). The B-PAH compound 100 is used to improve the properties of the OLED display 502, such as to improve thermal stability, internal quantum yield, power consumption, and lifespan of the OLED display 502. In accordance with an embodiment, the B-PAH compound 100 is deposited by thermal evaporation, the thermal evaporation technique helps in depositing the highest purity form of the B-PAH compound 100 because of low pressure. Moreover, the thermal evaporation is compatible with the OLED display 502.

FIG. 6 is a flow chart of a method of synthesizing a boron doped polycyclic aromatic hydrocarbon (B-PAH) compound, in accordance with an embodiment of the present disclosure. FIG. 6 is described in conjunction with elements from the FIGs. 1, 2, 3A to 31, 4, and 5. With reference to the FIG. 6, there is shown a flow chart of a method 600 of synthesizing the B-PAH compound 100. The method 600 includes steps 602 to 608.

At step 602, the method 600 comprises, mixing a substituted diarylalkyne compound and 2,4,6- tri-tert-butylpyridine (TBP) in a reaction vessel. In other words, the substituted diarylalkyne compound is used for the procedure. In an implementation, the substituted diarylalkyne compound includes a diarylalkyne unit and one or more aromatic nitrogen-doped donor units arranged on a periphery of the diarylalkyne unit. The substituted diarylalkyne compound is first filled in a reaction vessel for mixing with other compounds. In an implementation, the reaction vessel is a two-necked Schlenk flask. The two-necked Schlenk flask is a reaction vessel, which is typically used in air-sensitive chemistry. The shape of the two-necked Schlenk flask helps to easily fill or evacuate the gas. After filling the two-necked Schlenk flask with the substituted diarylalkyne compound, mixing is performed by adding the 2,4,6-tri-tert-butylpyridine (TBP) in the two-necked Schlenk flask.

In accordance with an embodiment, the mixing step comprises placing the mixture under argon. In other words, the mixing of the substituted diarylalkyne compound and the 2,4,6-tri-tert- butylpyridine is performed under the presence of argon, which acts as an inert gas with approximately similar solubility as oxygen and it is 2.5 times as soluble in water as nitrogen. This chemically inert element is colorless and odorless in both its liquid and gaseous forms.

In accordance with an embodiment, the substituted diarylalkyne compound and the 2,4,6-tri- tert-butylpyridine (TBP) are mixed at a ratio of 1: 1.5. In other words, the substituted diarylalkyne compounds (of 1.0 equiv.), and the TBP (of 1.5 equiv.) are charged under protection of argon. At step 604, the method 600 comprises, adding anhydrous 1,2,4- trichlorobenzene (TCB) and boron tribromide (BBr3). In other words, addition is performed in the mixture of the substituted diarylalkyne compound and the 2,4,6-tri-tert-butylpyridine. The mixture is further added with the anhydrous 1,2,4-trichlorobenzene and the boron tribromide. In an implementation, the ratio of the substituted diarylalkyne compound to the boron tribromide is of a ratio of 1 :3, which is maintained for accurate balancing between the compounds.

At step 606, the method 600 comprises, heating the mixture above a threshold temperature and stirring for at least a predetermined period of time. In other words, heating is performed after adding the anhydrous 1,2,4-trichlorobenzeneand the boron tribromide in the mixture of the substituted diarylalkyne compound and the 2,4,6-tri-tert-butylpyridine. In an implementation, the threshold temperature is 200°C and the predetermined period of time is 12 hours.

At step 608, the method 600 comprises, cooling to room temperature and adding a Grignard reagent (RMgBr). After heating the mixture, cooling is performed at room temperature. While cooling the mixture, Grignard reagent is added. Further, the step 608 includes stirring for at least one hour and reducing the pressure of the reaction vessel to remove volatile compounds. The volatile compounds have a high vapor pressure and low water solubility. After removing the volatile compound, the B-PAH compound 100 is purified by flash chromatography on silica gel. In an implementation, the ratio of substituted diarylalkyne compound to the TCB, BBr3 and Grignard reagent is 1:1, 1 :3, and 1 :4 respectively. For example, 4.0 equiv. of the Grignard reagents are used. In an implementation, the method 600 further comprises stirring for at least one hour and reducing the pressure of the reaction vessel to remove volatile compounds. Due to the reduction in pressure, it is easy to remove the volatile compounds

In an implementation, the method 600 further comprises purifying the B-PAH com-pound by flash chromatography on silica gel. After removing the volatile compound, the B-PAH compound 100 is purified by flash chromatography on silica gel.

The method Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a nonexclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

Claims

1. A boron doped polycyclic aromatic hydrocarbon, B-PAH, compound (100, 200) comprising: a Boron-doped dibenzophenalenyl unit (102); and one or more aromatic nitrogen-doped donor units (104) arranged on a periphery of the Boron-doped dibenzophenalenyl unit (102).

2. The B-PAH compound (100, 200) of claim 1, wherein at least one of the donor units is substituted for a hydrogen atom in the Boron-doped dibenzophenalenyl unit (102).

3. The B-PAH compound (100, 200) of claim 1 or claim 2, wherein at least one of the donor units is fused to the Boron-doped dibenzophenalenyl unit (102).

4. The B-PAH compound (100, 200) of any preceding claim, wherein at least one of the donor units is a carbazole unit.

5. The B-PAH compound (100, 200) of any preceding claim, configured to perform thermally activated delayed fluorescence.

6. An OLED display (502), comprising the B-PAH compound (100, 200) of any preceding claim.

7. The OLED display (502) of claim 6, wherein the B-PAH compound (100, 200) is deposited by thermal evaporation.

8. A method (600) of synthesizing a boron doped polycyclic aromatic hydrocarbon, B- PAH, compound (100, 200), comprising: mixing a substituted diarylalkyne compound and 2,4,6-tri-tert-butylpyridine, TBP, in a reaction vessel; adding anhydrous 1, 2, 4-tri chlorobenzene, TCB, and boron tribromide, BBr3; heating the mixture above a threshold temperature and stirring for at least a predetermined period of time; cooling to room temperature and adding a Grignard reagent, RMgBr.

9. The method (600) of claim 8, wherein the mixing step comprises placing the mixture under argon.

10. The method (600) of claim 8 or claim 9, wherein the substituted diarylalkyne compound and TBP are mixed at a ratio of 1 : 1.5

11. The method (600) of any one of claims 8 to 10, wherein the ratio of substituted diarylalkyne compound to BBr3 and Grignard reagent is 1:3 and 1:4 respectively.

12. The method (600) of any one of claims 8 to 11, wherein the reaction vessel is a twonecked Schlenk flask.

13. The method (600) of any one of claims 8 to 12, wherein the threshold temperature is

200°C and predetermined period of time is 12 hours.

14. The method (600) of any one of claim 8 to 13, further comprising stirring for at least 1 hour and reducing a pressure of the reaction vessel to remove volatile compounds.

15. The method (600) of claim 14, further comprising purifying the B-PAH compound (100, 200) by flash chromatography on silica gel.

16. The method (600) of any one of claims 8 to 15, wherein the substituted diarylalkyne compound comprises a diarylalkyne unit and one or more aromatic nitrogen-doped donor units arranged on a periphery of the diarylalkyne unit.