Application of chiral small organic molecule dopant in electroluminescent device based on PEDOT: PSS

Abstract

The invention belongs to the field of light emitting diodes, and particularly discloses application of a chiral small organic molecule dopant in an electroluminescent device based on PEDOT: PSS. The chiral small organic molecule dopant is simple in structure and has one or more chiral units. The organic chiral small molecular material and PEDOT: PSS are doped and the electroluminescent device is prepared, and the achiral luminescent material can emit circularly polarized light in the device, so that a circularly polarized light-emitting diode (CP-LED) with low turn-on voltage, high light-emitting color purity, high light-emitting efficiency and full-light color emission is obtained and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of light-emitting diodes, and particularly discloses application of a chiral organic small-molecule dopant in a PEDOT:PSS-based electroluminescent device. BACKGROUND

[0002] Circularly polarized luminescence (CPL) reflects the different emission intensities of left and right circularly polarized light, and has strong advantages in optoelectronic applications such as data storage, chiral sensing and light-emitting diodes (LEDs). Generally, in order to prevent interference of external light, an anti-glare filter needs to be installed on an LED display screen, which causes at least 50% energy loss. In theory, a circularly polarized light-emitting diode (CP-LED) can produce circularly polarized electroluminescence (CPEL), which can avoid energy loss in the process of passing through an anti-glare filter. Chiral luminescent materials are one of the important ways to obtain CPEL.

[0003] Organic chiral luminescent materials include organic small-molecule fluorescent materials, iridium platinum and other metal phosphorescent materials, and pure organic thermally activated delayed fluorescence (TADF) materials, which have been widely used in high-performance organic light-emitting devices. In addition, in order to meet people's demand for high-definition display, LEDs use filters and / or optical microcavities to narrow the electroluminescence peak width, so as to reach the color gamut standard of NTSC or BT.2020, but these methods significantly reduce the external quantum efficiency (EQE) of the device. Emerging multiple resonance-thermally activated delayed fluorescence (MR-TADF) and inorganic quantum dots and perovskite luminescent materials have the characteristics of narrow spectrum and high efficiency of luminescence, and can reach the color gamut standard of NTSC or BT.2020 without filters and other accessory facilities, thereby simplifying the device structure. Luminescent materials that can simultaneously achieve circularly polarized luminescence and narrow spectrum, such as circularly polarized-multiple resonance-thermally activated delayed fluorescence (CP-MR-TADF) and chiral two-dimensional perovskite, can not only avoid energy loss caused by external light, but also emit narrow spectrum, thereby simplifying the device structure, so that such materials have developed rapidly. However, chiral luminescent materials may encounter disadvantages such as racemization, chiral resolution and long synthesis period during synthesis and preparation.

[0004] Circularly polarized light-emitting diodes (CP-LEDs) have been developed so far, mainly based on chiral luminescent materials to obtain circularly polarized light, and the electroluminescence asymmetry factor (g EL ) value is mostly around 10 -3 , and each luminescent material corresponds to only one color of light. In order to reduce the cost of constructing chiral luminescent devices, it is necessary to avoid tedious chiral synthesis and chiral resolution. SUMMARY

[0005] In view of the deficiencies of the circularly polarized light-emitting device as pointed out in the background art, the present application bypasses the development of chiral light-emitting materials, and prepares a hole injection layer by blending a chiral additive with PEDOT:PSS, and prepares devices of various colors of non-chiral light-emitting materials based on the hole injection layer and endows them with circularly polarized light-emitting function, and the g EL value is high, and has wide universality for non-chiral light-emitting materials; in addition, such a hole injection layer is not only suitable for organic light-emitting diodes (OLED) based on organic light-emitting materials, but also suitable for light-emitting diodes (LED) based on inorganic light-emitting materials such as perovskite and quantum dots, and has universality for different types of devices. A series of non-chiral light-emitting materials selected in the present application have the following structure:

[0007] Formula 1. Structure of non-chiral light-emitting material

[0008] In order to achieve the above-mentioned purpose, the present application adds an organic chiral small molecule as an additive to PEDOT:PSS to prepare a hole injection layer film, and compares it with a PEDOT:PSS hole injection layer film without additive, and the structure of the organic chiral small molecule is as follows:

[0009] Formula 2. Structure of chiral additive

[0010] The present application uses a series of water-soluble organic chiral small molecules as dopants, which are added to PEDOT:PSS (the mass percentage of the organic chiral small molecule dopant is 1-4%), and a hole injection layer in an electroluminescent device is prepared, and an electroluminescent device emitting circularly polarized light and having excellent performance is prepared based on the hole injection layer. The influence of the doping of the chiral small molecule on the maximum external quantum efficiency and g EL is also studied, which is of great significance for exploring efficient circularly polarized light-emitting devices.

[0011] Another object of the present application is to explore the influence of the doping of the organic small molecule on the carrier transport performance of the hole injection layer, so as to obtain an electroluminescent device with more excellent maximum external quantum efficiency.

[0012] The above-mentioned organic chiral small molecule is added as an additive to PEDOT:PSS as a hole injection layer film, and an electroluminescent device is prepared by solution processing, and a maximum external quantum efficiency (EQE max ) of >20% is obtained, and the device is endowed with circularly polarized light-emitting performance. Compared with the prior art, the technical scheme of the present application has the following beneficial effects: 1. This invention improves the maximum external quantum efficiency of electroluminescent devices by adding organic chiral small molecules to the PEDOT:PSS system to obtain a hole injection layer with better carrier transport performance.

[0013] 2. By adding small organic chiral molecules to the hole injection layer, the circularly polarized light function of electroluminescent devices can be imparted. This is of great significance for the fabrication of circularly polarized light-emitting devices. This strategy can yield multi-color, narrow-spectrum, and high-g light. EL The invention of circularly polarized light-emitting devices expands the construction methods of circularly polarized light-emitting devices and is of great significance for designing high-efficiency circularly polarized light-emitting devices.

[0014] 3. The series of small molecules selected as dopants do not change the PEDOT:PSS energy level for the hole injection layer and do not reduce the carrier transport performance. This has important implications for the study of PEDOT:PSS layer modification. Through this series of doping controls, we can obtain a guiding scheme for interface modification to control device performance.

[0015] 4. The selected series of chiral small molecules are inexpensive, commercially available, water-soluble, and pollution-free. These low-cost chiral dopants induce various achiral luminescent materials to emit high gamma rays. EL The circularly polarized luminescence strategy has significant advantages in price, performance, and universality compared to currently used chiral luminescent materials. Attached Figure Description

[0016] 【 Figure 1 [Image 1] is an EL image of the electroluminescent device prepared in Example 1 of this invention.

[0017] 【 Figure 2 [Image 1] shows the EQE diagram of the electroluminescent device prepared in Example 1 of this invention.

[0018] 【 Figure 3 [Image 1] is the JVL diagram of the electroluminescent device prepared in Example 1 of this invention.

[0019] 【 Figure 4 [Image 1] is the EL spectrum of the electroluminescent device prepared in Example 2 of this invention.

[0020] 【 Figure 5 [Image 1] shows the EQE diagram of the electroluminescent device prepared in Example 2 of this invention.

[0021] 【 Figure 6 [Image 1] is the JVL diagram of the electroluminescent device prepared in Example 2 of this invention.

[0022] 【 Figure 7 [Image 1] is the EL spectrum of the electroluminescent device prepared in Example 3 of this invention.

[0023] 【Figure 8 [Image 1] shows the EQE diagram of the electroluminescent device prepared in Example 3 of this invention.

[0024] 【 Figure 9 [Image 1] is the JVL diagram of the electroluminescent device prepared in Example 3 of this invention.

[0025] 【 Figure 10 [Image showing the film thickness of the films prepared in Examples 4, 5, and 6 of this invention]

[0026] 【 Figure 11 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 1 of this invention.

[0027] 【 Figure 12 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 2 of this invention.

[0028] 【 Figure 13 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 3 of this invention.

[0029] 【 Figure 14 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 7 of this invention.

[0030] 【 Figure 15 [Image 1] is an EL image of the electroluminescent device prepared in Example 7 of this invention.

[0031] 【 Figure 16 [Image 1] shows the EQE diagram of the electroluminescent device prepared in Example 7 of this invention.

[0032] 【 Figure 17 [Image 1] is the JVL diagram of the electroluminescent device prepared in Example 7 of this invention.

[0033] 【 Figure 18 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 8 of this invention.

[0034] 【 Figure 19 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 9 of this invention.

[0035] 【 Figure 20 [Image caption: CPEL spectrum of the electroluminescent device prepared in Example 10 of this invention]

[0036] 【 Figure 21 [Image 1] is the CPEL spectrum of the electroluminescent device prepared in Example 11 of this invention. Detailed Implementation

[0037] The following specific implementation examples are intended to further illustrate the present invention, but these specific implementation examples do not limit the scope of protection of the present invention in any way.

[0038] Example 1: D-proline was doped into a PEDOT:PSS aqueous solution at a ratio of 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt% to form a mixed solution, PEDOT:PSS-D-Proline. The solution was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer, and then spin-coated at 3000 rpm / min to prepare a thin film. The performance of the resulting electroluminescent device was investigated. The device structure was ITO / PEDOT:PSS-D-Proline (20 nm) / mCP:Ir(mppy)3 (20 wt%) (40 nm) / TmPyPB (55 nm) / LiF (1 nm) / Al (100 nm), where PEDOT:PSS-D-Proline was the hole injection layer, the mCP:Ir(mppy)3 (20 wt%) blend was the light-emitting layer, TmPyPB was the electron transport layer, and LiF / Al was the cathode. It can be clearly seen that its peak values ​​are all around 514 nm, and through Figure 3 It can be seen that when the doping ratio is 1wt%, EQE max It was 24.3%, g EL = 0.022. From the EQE diagram of the electroluminescent device, it can be seen that the EQE obtained with 1wt% doping... max The g-value is higher than that of the undoped D-proline PEDOT:PSS film, indicating that a small amount of D-proline doping has a certain improving effect on carrier transport performance and film formation. Since chiral D-proline is blended with PEDOT:PSS and then spin-coated into a film, a hole injection layer capable of generating chiral properties is formed. This is a novel electro-induced circularly polarized light emission construction strategy, and the g-value of the generated circularly polarized light is... EL Greater than traditional strategies.

[0039] Example 2: L-VC was doped into a PEDOT:PSS aqueous solution at a ratio of 0wt%, 1wt%, 2wt%, 3wt%, and 4wt% to obtain a mixed solution called PEDOT:PSS-L-VC. The PEDOT:PSS-L-VC solution was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer, and then a thin film was prepared by spin-coating at 3000 rpm / min using a spin coater. The performance of the electroluminescent device was studied. The device structure was ITO / PEDOT:PSS-L-VC (70 nm) / mCP:Ir(mppy)3 (20wt%) (40 nm) / TmPyPB (55 nm) / LiF (1 nm) / Al (100 nm), where PEDOT:PSS-L-VC was the hole injection layer, mCP:Ir(mppy)3 (20wt%) was the light-emitting layer, TmPyPB was the electron transport layer, and LiF / Al was the cathode. It can be clearly seen that its peak values ​​are all around 514 nm, and through Figure 6 It can be seen that when the doping ratio is 3wt%, EQE max It is 22.1%, g EL = 0.028. The EQE plot of the electroluminescent device shows that the EQE obtained with 3wt% doping is... max The results are higher than those of undoped L-VC PEDOT:PSS films, indicating that a small amount of L-VC doping has a certain improving effect on carrier transport performance and film formation performance. On the other hand, L-VC has reducing properties, which can eliminate the influence of oxygen on PEDOT:PSS films to a certain extent during film preparation.

[0040] Example 3: Camphor sulfonic acid was doped into PEDOT:PSS aqueous solution at a ratio of 0 wt% and 0.9 wt% to obtain a mixed solution of PEDOT:PSS-R-Camphorsulfonic acid. The PEDOT:PSS-R-Camphorsulfonic acid solution was stirred at 500 rpm / min for 5 minutes with a magnetic stirrer, and a thin film was prepared by spin coating at 3000 rpm / min using a spin coater. The performance of the electroluminescent device was studied. Its device structure is ITO / PEDOT:PSS-R-Camphorsulfonic acid (40 nm) / mCP:Ir(mppy)3 (20wt%) (40 nm) / TmPyPB (55 nm) / LiF (1 nm) / Al (100 nm), where PEDOT:PSS-R-Camphorsulfonic acid is the hole injection layer, mCP:Ir(mppy)3 (20wt%) blend is the light-emitting layer, TmPyPB is the electron transport layer, and LiF / Al is the cathode. It can be clearly seen that its peak values ​​are all around 514 nm, and through… Figure 9 It can be seen that when the doping ratio is 0.9wt%, the maximum EQE is 13.2%, g EL =0.0063.

[0041] Example 4: D-proline was doped into PEDOT:PSS at ratios of 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt% to obtain a mixed solution, PEDOT:PSS-D-Proline. The PEDOT:PSS-D-Proline solution was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer to investigate its effect on film thickness. Thin films were prepared by spin-coating at 3000 rpm / min using a spin coater, and the film thickness was measured using a film thickness gauge (characterization results are in...). Figure 10 ).

[0042] Example 5: VC was doped into PEDOT:PSS at ratios of 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt% to obtain a mixed solution, PEDOT:PSS-L-VC. The PEDOT:PSS-L-VC solution was stirred with a magnetic stirrer at 500 rpm / min for 5 minutes to investigate its effect on film thickness. Thin films were prepared by spin coating at 3000 rpm / min using a spin coater, and the film thickness was measured using a film thickness gauge (characterization results are in...). Figure 10 ).

[0043] Example 6: Camphor sulfonic acid was doped into PEDOT:PSS at a ratio of 0 wt% and 0.9 wt% to obtain a mixed solution of PEDOT:PSS-R-Camphorsulfonic acid. The PEDOT:PSS-R-Camphorsulfonic acid solution was stirred with a magnetic stirrer at 500 rpm / min for 5 minutes to study its effect on film thickness. Thin films were prepared by spin coating at 3000 rpm / min using a spin coater, and the film thickness was measured using a film thickness gauge (characterization results are in...). Figure 10 ).

[0044] Example 7: Using v-DABNA as the luminescent material, PhCzBCz as the host material, and 4TCzBN as the sensitizer, the influence of chiral luminescent materials on the performance and circular polarization properties of electroluminescent devices was investigated. Specifically, 1 wt% L-proline was doped into a PEDOT:PSS aqueous solution (labeled 1 wt%-PEDOT:PSS-L-Proline, referring to Example 1), 1 wt% D-proline was doped into a PEDOT:PSS aqueous solution (labeled 1 wt%-PEDOT:PSS-D-Proline), 3 wt% L-VC was doped into a PEDOT:PSS aqueous solution (labeled 3 wt%-PEDOT:PSS-L-VC, referring to Example 2), and 3 wt% D-VC was doped into a PEDOT:PSS aqueous solution (labeled 3 wt%-PEDOT:PSS-D-VC). The chiral additive-PEDOT:PSS solution (collectively referred to as chiral additive-PEDOT:PSS) was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer. A thin film was then prepared by spin-coating at 3000 rpm / min using a spin coater. An electroluminescent device was then fabricated based on this hole injection layer film: ITO / chiral additive-PEDOT:PSS / PhCzBCz:4TCzBN (20%):v-DABNA (1.0%) (30nm) / TmPyPB (55nm) / LiF (1nm) / Al (120nm), where chiral additive-PEDOT:PSS is the hole injection layer, the PhCzBCz:4TCzBN (20%):v-DABNA (1.0%) blend is the light-emitting layer, TmPyPB is the electron transport layer, and LiF / Al is the cathode. Among them, the g obtained by CP-OLED based on 1wt%-PEDOT:PSS-L-Proline EL=-0.0039, with a maximum EQE of 16.6%. Additionally, the g obtained from CP-OLED prepared based on 1wt%-PEDOT:PSS-D-Proline... EL =0.014, with a maximum EQE of 16.0%. Among them, the g obtained from the CP-OLED prepared based on 3wt%-PEDOT:PSS-L-VC... EL =0.022, with a maximum EQE of 17.2%. Additionally, the g obtained from the CP-OLED prepared based on 3wt%-PEDOT:PSS-D-VC... EL =0.018, with a maximum EQE of 15.1%.

[0045] Example 8: Using BN5 as the luminescent material, PhCzBCz as the host material, and 4TCzBN as the sensitizer, the influence of non-chiral luminescent materials on the performance and circular polarization properties of electroluminescent devices was investigated. Specifically, 1 wt% L-proline was doped into a PEDOT:PSS aqueous solution (labeled 1 wt%-PEDOT:PSS-L-Proline, referring to Example 1), 1 wt% D-proline was doped into a PEDOT:PSS aqueous solution (labeled 1 wt%-PEDOT:PSS-D-Proline), 3 wt% L-VC was doped into a PEDOT:PSS aqueous solution (labeled 3 wt%-PEDOT:PSS-L-VC, referring to Example 2), and 3 wt% D-VC was doped into a PEDOT:PSS aqueous solution (labeled 3 wt%-PEDOT:PSS-D-VC). The chiral additive-PEDOT:PSS solution (collectively referred to as chiral additive-PEDOT:PSS) was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer. A thin film was then spin-coated at 3000 rpm / min using a spin coater. An electroluminescent device was then fabricated based on this hole injection layer film: ITO / chiral additive-PEDOT:PSS / PhCzBCz:4TCzBN (20%):BN5 (2.0%) (30nm) / TmPyPB (55nm) / LiF (1nm) / Al (120nm), where chiral additive-PEDOT:PSS is the hole injection layer, the PhCzBCz:4TCzBN (20%):BN5 (2.0%) blend is the light-emitting layer, TmPyPB is the electron transport layer, and LiF / Al is the cathode. Among them, the g obtained by CP-OLED based on 1wt%-PEDOT:PSS-L-Proline EL=-0.002, with a maximum EQE of 21.0%. Additionally, the g obtained from CP-OLED prepared based on 1wt%-PEDOT:PSS-D-Proline... EL =0.001, with a maximum EQE of 21.5%. Among them, the g obtained from the CP-OLED prepared based on 3wt%-PEDOT:PSS-L-VC EL =0.001, with a maximum EQE of 23.0%. Additionally, the g obtained from CP-OLED prepared based on 3wt%-PEDOT:PSS-D-VC... EL =0.005, with a maximum EQE of 22.9%.

[0046] Example 9: Using tCzBN as the luminescent material, PhCzBCz as the host material, and 4TCzBN as the sensitizer, the influence of chiral luminescent materials on the performance and circular polarization properties of electroluminescent devices was investigated. Specifically, 1 wt% L-proline was doped into a PEDOT:PSS aqueous solution (labeled 1 wt%-PEDOT:PSS-L-Proline, referring to Example 1), 1 wt% D-proline was doped into a PEDOT:PSS aqueous solution (labeled 1 wt%-PEDOT:PSS-D-Proline), 3 wt% L-VC was doped into a PEDOT:PSS aqueous solution (labeled 3 wt%-PEDOT:PSS-L-VC, referring to Example 2), and 3 wt% D-VC was doped into a PEDOT:PSS aqueous solution (labeled 3 wt%-PEDOT:PSS-D-VC). The chiral additive-PEDOT:PSS solution (collectively referred to as chiral additive-PEDOT:PSS) was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer. A thin film was then prepared by spin-coating at 3000 rpm / min using a spin coater. An electroluminescent device was then fabricated based on this hole injection layer film: ITO / chiral additive-PEDOT:PSS / PhCzBCz:4TCzBN (20%):tCzBN (1.5%) (30nm) / TmPyPB (55nm) / LiF (1nm) / Al (120nm), where chiral additive-PEDOT:PSS is the hole injection layer, the PhCzBCz:4TCzBN (20%):tCzBN (1.5%) blend is the light-emitting layer, TmPyPB is the electron transport layer, and LiF / Al is the cathode. Among them, the g obtained by CP-OLED based on 1wt%-PEDOT:PSS-L-ProlineEL =-0.004, with a maximum EQE of 18.2%. Additionally, the g obtained from CP-OLED prepared based on 1wt%-PEDOT:PSS-D-Proline... EL =0.009, with a maximum EQE of 18.5%. Among them, the g obtained from the CP-OLED prepared based on 3wt%-PEDOT:PSS-L-VC EL =0.006, with a maximum EQE of 20.3%. Additionally, the g obtained from the CP-OLED prepared based on 3wt%-PEDOT:PSS-D-VC... EL =0.001, with a maximum EQE of 22.3%.

[0047] Example 10: To study the application of chiral additives in quantum dot electroluminescent devices, D-proline / L-proline was used as a dopant at a certain ratio (1wt%) to PEDOT:PSS, resulting in a mixed solution of 1wt%-PEDOT:PSS-D / L-Proline. The 1wt%-PEDOT:PSS-D / L-Proline solution was stirred at 500 rpm / min for 5 minutes using a magnetic stir bar, and a thin film was prepared by spin coating at 3000 rpm / min using a spin coater. The performance of the hole injection layer electroluminescent device based on this film was studied. Its device structure is ITO / 1wt%-PEDOT:PSS-D / L-Proline (20 nm) / Quantum Dot (40 nm) / TmPyPB (55 nm) / LiF (1 nm) / Al (120 nm), where Quantum Dot is InP / ZnSeS / ZnS QD, 1wt%-PEDOT:PSS-D / L-Proline is the hole injection layer, the blend is the light-emitting layer, TmPyPB is the electron transport layer, and LiF / Al is the cathode. It can be clearly seen that its peak values ​​are all around 543 nm. EL = 0.0034 and g EL = -0.0025.

[0048] Scalable InP / ZnSeS / ZnS QDs were prepared using a colloidal synthesis method. First, 0.99 g InI3, 2.93 g ZnBr2, and 50.0 mL OAm were mixed in a flask. The solution was heated to 120 °C at a rate of 10 °C / min and degassed for 20 min. The mixture was then heated to 200 °C, and 4.5 mL (24.0 mmol) of (DMA)3P (tris(dimethylamino)phosphine) was added. After holding at 200 °C for 5 min, 120 mL of a zinc precursor solution (30.0 g Zn(St)2 dissolved in 120.0 mL ODE) and 12.0 mmol (2.2 M) TOP / (Se+S) were injected into the reaction solution, and the mixture was heated to 260 °C and held for 120 min. Finally, 15.0 mL of DDT was injected into the solution at 280 °C and held for 1 h. The product was centrifuged and washed three times with acetone, then suspended in chloroform for further use.

[0049] Example 11: To investigate the application of chiral additives in perovskite quantum dot electroluminescent devices, D-proline / L-proline was used as a dopant at a certain ratio (1 wt%) to dope PEDOT:PSS, resulting in a mixed solution of 1 wt% PEDOT:PSS-D / L-Proline. The 1 wt% PEDOT:PSS-D / L-Proline solution was stirred at 500 rpm / min for 5 minutes using a magnetic stirrer. Thin films were then spin-coated at 3000 rpm / min using a spin coater to prepare the electroluminescent device. The device structure was ITO / 1 wt% PEDOT:PSS-D / L-Proline (20 nm) / P8PB2 (40 nm) / TPBi (55 nm) / LiF (1 nm) / Al (150 nm). In this composition, 1wt%-PEDOT:PSS-D / L-Proline serves as the hole injection layer, the blend acts as the luminescent layer, TPBi is the electron transport layer, and LiF / Al is the cathode. It is evident that the peak values ​​are all around 674 nm. EL = 0.0023 and g EL = -0.0015.

[0050] Here, the optimized perovskite formulation is (PA) 0.8 PBA 0.2 ) 0.6 Cs 1.2 Pb(I 0.7 / Br 0.33. A single-step spin-coating process will be used as the perovskite emitting unit. Based on the relative contents of PAI and PBAI (8:2), the selected perovskite is also called P8PB2 red perovskite. PAI and PBAI are used to form a quasi-2D perovskite structure with a narrow phase distribution. Excess CsI is used to passivate defects on the perovskite grain surface. Tunable red light emission is achieved using mixed halide ions (I / Br).

[0051] Preparation of perovskite thin films: To prepare P8PB2 perovskite thin films, CsI, PbI2, PbBr2, PAI, and PBAI were dissolved in 0.6 mmol / mL solution. -1 In (M) DMS (dimethyl sulfate), the mixture was stirred overnight at 45 °C. A P8PB2 perovskite precursor solution was prepared by mixing PAI, PBAI, CsI, PbI2, and PbBr2 in a molar ratio of 0.48:0.12:1.2:0.7:0.3. The molar concentration of PbI2 and PbBr2 was finely adjusted to 0.13 μm by adding an appropriate volume of DMSO solvent. After preheating for approximately 2 h, the precursor solution was spin-coated for 60 s at 6000 rpm / min without the use of any antisolvent to prepare a 40 nm perovskite film.

[0052] ITO / 1wt%-PEDOT:PSS-D / L-Proline (20 nm) / P8PB2 (40 nm) / TPBI (55 nm) / LiF (1 nm) / Al (150 nm).

[0053] Table 1 Performance parameters of the electroluminescent devices prepared in the embodiments of the present invention:

[0054]

[0055] Although the invention has been described in conjunction with preferred embodiments, the invention is not limited to the above embodiments, and it should be understood that the appended claims summarize the scope of the invention. Guided by the inventive concept, those skilled in the art should recognize that any modifications made to the various embodiments of the invention will be covered by the spirit and scope of the claims.

Claims

1. An application of a chiral organic small molecule dopant, characterized in that, The chiral organic small molecule dopant is used to prepare electroluminescent devices based on PEDOT:PSS; The molecular structure of the chiral organic small molecule dopant is as follows: 。 2. The application of the chiral organic small molecule dopant according to claim 1, characterized in that, The chiral organic small molecule dopant is used as an additive for the hole injection layer PEDOT:PSS in PEDOT:PSS-based electroluminescent devices.

3. The application of the chiral organic small molecule dopant according to claim 2, characterized in that, The mass percentage of chiral organic small molecule dopants in PEDOT:PSS is 1-4 wt%.

4. The application of the chiral organic small molecule dopant according to claim 1, characterized in that, Electroluminescent devices are quantum dot, perovskite, or organic electroluminescent devices.

5. The application of the chiral organic small molecule dopant according to claim 1, characterized in that, The hole injection layer of the electroluminescent device is prepared by solution processing.

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