阅读说明：本技术 基于非对称噻吩并异苯并吡喃单元的有机小分子受体材料及应用 (Organic small molecule receptor material based on asymmetric thieno-isobenzopyran units and application ) 是由 朱卫国 郭佳莉 朱佳宁 朱梦冰 唐炜 孙大伟 于 2021-08-24 设计创作，主要内容包括：本发明涉及有机光伏领域,特别涉及一类基于非对称噻吩并异苯并吡喃的有机小分子受体材料及应用。该类有机小分子受体材料具有A-D-D'-A型骨架,包含噻吩并异苯并吡喃和环戊二烯并二噻吩双电子给体(D-D')单元,以及氰基茚酮衍生物强电子受体(A)末端单元。这类有机小分子受体材料结构简单,具有合成步骤简单、非骨架偶极矩和骨架偶极矩的双重作用,能有效调节材料的分散、结晶、吸收、电化学和载流子传输等性能；能与大多数给体材料组合,构建高效的本体异质结二元有机太阳能电池(OSCs)。(The invention relates to the field of organic photovoltaics, in particular to an organic small molecule receptor material based on asymmetric thienoisobenzopyran and application thereof. The organic small molecule acceptor material has an A-D-D '-A type framework, and comprises a thienoisobenzopyran, a cyclopentadithiophene double electron donor (D-D') unit and a cyano-indanone derivative strong electron acceptor (A) terminal unit. The organic micromolecule receptor material has simple structure, has the double functions of simple synthesis steps and non-framework dipole moment and framework dipole moment, and can effectively adjust the properties of the material such as dispersion, crystallization, absorption, electrochemistry, carrier transmission and the like; can be combined with most donor materials to construct efficient bulk heterojunction binary Organic Solar Cells (OSCs).)

1. A class of organic small molecule acceptor materials based on asymmetric thieno-isobenzopyran is characterized in that the structure of the materials is shown as the following formula:

2. the use of the small organic molecule acceptor material according to claim 1, wherein the small organic molecule acceptor material is used in a photoactive layer of an organic solar cell.

3. The use of the small organic molecule acceptor material according to claim 2, wherein the small organic molecule acceptor material is blended with a commercially available polymer donor material to make a formal or trans device of the binary bulk heterojunction organic solar cell.

4. The application of the organic small molecule acceptor material as claimed in claim 3, wherein the organic solar cell device comprises an indium tin oxide conductive glass anode, a cathode modification layer, a photoactive layer, an anode modification layer and a cathode.

5. The use of the small organic molecule acceptor material according to claim 3, wherein the weight ratio of the acceptor to the donor is 1:1.2-1: 1.

Technical Field

The invention relates to the field of organic photovoltaics, in particular to an organic small molecule acceptor material based on an asymmetric thienoisobenzopyran unit and application of the material as an electron acceptor material in a photoactive layer in the field of organic solar cells.

Background

The organic solar cell has the outstanding advantages of light weight, wide material source, adjustable molecular structure, realization of large-area flexible device preparation and the like, and becomes an important direction for the development of new energy at present.

The active layer material is a key factor for determining the performance of the organic solar cell and mainly consists of a donor material and an acceptor material. After decades of research, some electron donor materials and electron acceptor materials with excellent performance, such as PBDB-T, PM6, J71, etc., have been developed. Among them, the emerging non-fullerene small molecule acceptor material has the advantages of wide raw material source, easy adjustment of absorption spectrum, high molar extinction coefficient and the like, and can be matched with various donor materials to prepare high-efficiency and low-cost solar cells, and the development is rapidly carried out in recent years.

Most of reported non-fullerene small molecule acceptor (NF-SMA) materials have high energy conversion efficiency and comprise multi-condensed-ring complex structural units, and the NF-SMA materials have high synthesis difficulty and relatively high cost and are not beneficial to large-scale practical application.

Disclosure of Invention

The invention aims to provide an asymmetric A-D-D' -A type micromolecule receptor material with novel and simple structure. A-D-D '-A type asymmetric micromolecule acceptor material is constructed by adopting three-condensed-ring asymmetric thienoisochroman with a simple structure as a first electron donor (D) unit and three-condensed-ring symmetric dithienocyclopentadiene as a second electron donor (D') unit. The dipole moment action of the thienoisobenzopyran units and the pi-pi action among molecules are utilized to adjust the D-A action in the molecules and the interaction among the molecules, improve the appearance of an optical active layer and the transmission capability of current carriers, and improve the photovoltaic performance of the organic solar cell.

The asymmetric structure gives the material a certain dipole moment, the combination of the strong electron donating unit and the strong electron withdrawing unit also enables the molecule to have stronger D-A effect, and the material has wide and strong visible or even near infrared absorption. The asymmetric micromolecule acceptor material and the polymer donor material are blended through a solution processing method to manufacture non-fullerene Organic Solar Cells (OSCs), and the high-efficiency energy conversion of the micromolecule material in the OSCs can be realized.

The molecular structure of the asymmetric A-D-D' -A type micromolecule receptor material provided by the invention can be one of the following molecules.

The application of the invention is that: the designed and developed asymmetric A-D-D' -A type organic micromolecule acceptor material is used as an optical active layer acceptor material and is mixed with a commercially purchased polymer donor material in different proportions to manufacture a bulk heterojunction organic solar cell device, so that the high-efficiency photoelectric conversion of the device is realized.

The organic solar cell device comprises an Indium Tin Oxide (ITO) conductive glass anode, a cathode modification layer, an optical activity layer, an anode modification layer and a cathode. The active layer material is the small molecule acceptor material and the polymer donor material which is purchased commercially. Wherein the weight ratio of the donor to the acceptor is 1:1.2-1: 1.

The asymmetric A-D-D' -A type micromolecule receptor material provided by the invention has the following characteristics:

(1) the combination of asymmetric thienoisobenzopyran units and symmetric dithienocyclopentadiene units in molecules can regulate and control the crystallization property and absorption property of the material and improve the appearance of an optical active layer;

(2) compared with the traditional symmetrical micromolecule receptor material, the asymmetrical A-D-D' -A type micromolecule receptor material has the double functions of non-framework dipole moment and framework dipole moment, can regulate and control the interaction of molecules and the carrier transmission performance of the material, and the characteristics promote the receptor material to show excellent photovoltaic performance in an organic solar cell.

(3) Compared with the traditional symmetrical structure, the asymmetrical A-D-D' -A structure has a certain dipole moment to eliminate the polarity of the system, avoid the space effect caused by parallel stacking of side chains, enlarge the stacking area and strength and enhance the acting force among molecules.

Description of the drawings:

FIG. 1 is a UV-VIS spectrum of CPDT-TiC-2DFCN and CPDT-TiC-2DClCN of the present invention;

FIG. 2 is a cyclic voltammogram of CPDT-TiC-2DFCN and CPDT-TiC-2DClCN of the present invention;

FIG. 3 is a PM6 of the present invention: CPDT-TiC-2DFCN and PM6: J-V curve of CPDT-TiC-2DClCN organic solar cell device;

FIG. 4 is a PM6 of the present invention: CPDT-TiC-2DFCN and PM6: EQE curve of CPDT-TiC-2DClCN organic solar cell device.

Detailed Description

The invention is further illustrated by the following specific examples, which are not intended to limit the scope of the invention in any way.

Example 1

And (3) synthesizing an asymmetric A-D-D' -A type micromolecule receptor material CPDT-TiC-2DFCN based on the thienoisobenzopyran unit.

The synthetic route of CPDT-TiC-2DFCN is as follows:

1.12 Synthesis of (tributyltin) -3-methoxythiophene (2)

Compound 1(43.86mmol,5.00g) was placed in a 250mL dry three-necked flask, 70mL dry n-hexane was added, dissolved by magnetic stirring, and n-butyllithium n-hexane solution (2.5M,19.30mL) was added dropwise at-25 ℃ under nitrogen protection, reacted for 0.5h, allowed to naturally warm to room temperature and reacted for 1 h. Then, the temperature was reduced to-25 ℃ and tributyltin chloride (50.44mmol,16.39g) was added to the mixture, and the mixture was warmed to room temperature again to react for 12 hours. The reaction mixture was poured into 90mL of water, extracted with petroleum ether (3X 30mL), and the light yellow organic phase was collected, followed by washing the organic phase with saturated potassium carbonate solution (3X 45 mL). Collecting organic phase, drying with anhydrous magnesium sulfate, distilling under reduced pressure to remove organic solvent, and vacuum drying to obtain red liquid compound 2(14.90g, produced byThe rate was 85%).¹H NMR(400MHz,CDCl₃)δ7.50(d,J＝4.9Hz,1H),7.00(d,J＝4.9Hz,1H),3.80(s,3H),1.16-1.07(m,6H),0.91(t,J＝7.3Hz,21H)。

1.2 Synthesis of Compound 4

Compound 2(37.10mmol,14.94g), compound 3(44.50 mmol, 15.17g), bis (triphenylphosphine) palladium dichloride was added to a 500mL one-neck flask in sequence, dissolved in 200mL toluene, stirred magnetically, heated to 110 ℃ under nitrogen, reacted for 12h, cooled to room temperature. The organic solvent was removed by distillation under the reduced pressure, and the residue was subjected to column chromatography using a mixed solvent of petroleum ether and dichloromethane (v: v,3:1) as an eluent to give compound 4(11.00g, yield 91%) as a yellow viscous liquid.¹H NMR(400MHz,CDCl₃)δ7.95(d,J＝2.2Hz,1H),7.62(dd,J＝8.3,2.2Hz,1H)，7.32(d,J＝8.3Hz,1H)，7.30–7.25(m,1H),6.89(d,J＝5.5Hz,1H)，3.80(s,6H),1.62(s,1H),0.03(s,1H)。

1.3 Synthesis of Compound 5

Adding compound 4(33.60mmol,11.00g) into a 500mL single-neck flask, adding 200mL dichloromethane for dissolution, magnetically stirring, and dropwise adding 19.10mL BBr under ice-water bath under nitrogen protection₃The reaction was continued for 10min, then warmed to room temperature again for 6 h. The organic solvent was removed by distillation under the reduced pressure, and the residue was subjected to column chromatography using a mixed solvent of petroleum ether/dichloromethane (v: v,1:1) as an eluent to give compound 5(8.30g, yield 71%) as a white crystalline solid powder.¹H NMR(400MHz,CDCl₃)δ8.49(d,J＝2.1Hz,1H),7.85(dd,J＝8.4,2.1Hz,1H)，7.49(d,J＝8.4Hz,1H)，7.44(d,J＝5.5Hz,1H)，7.07(d,J＝5.4Hz,1H)。

1.4 Synthesis of Compound 6

Compound 5(1.79mmol,0.50g) was added to a 100mL dry three-necked flask, dissolved in 30mL anhydrous tetrahydrofuran, stirred magnetically, added dropwise to a freshly prepared n-octyl magnesium bromide reagent (9.50mL,7.14 mmol) under nitrogen in an ice-water bath at 0 ℃ and stirred at room temperature for 12 h. Adding water to quench reaction, washing organic phase with diluted hydrochloric acid for 3 times, drying with anhydrous magnesium sulfate, distilling under reduced pressure to remove organic solvent, eluting residue with petroleum ether/dichloromethane mixed solvent (v: v,4:1), and separating by column chromatographyCompound 6(0.53g, 58% yield) was obtained as a yellow viscous liquid.¹H NMR(400MHz,CDCl₃)δ7.32(dd,J＝8.2,1.9Hz,1H),7.12(d,J＝1.9Hz,1H),7.09(d,J＝5.3Hz,1H),7.04(d,J＝8.2Hz,1H),6.66(d,J＝5.3Hz,1H),1.93–1.80(m,4H),1.36(s,1H),1.24(d,J＝13.5Hz,24H),0.86(t,J＝6.9Hz,7H).

1.5 Synthesis of Compound 7

Compound 6(1.04mmol,0.53g), p-toluenesulfonic acid (0.11mml,19.77mg) were added sequentially to a 100mL single-necked flask, dissolved in 40mL of toluene, magnetically stirred, heated to 135 ℃ under nitrogen, reacted for 4h, and cooled to room temperature. The organic solvent was removed by distillation under the reduced pressure, and the residue was subjected to column chromatography using petroleum ether as an eluent to give compound 7(0.40g, yield 78%) as a pale yellow viscous liquid.¹H NMR(400MHz,CDCl₃)δ7.32(dd,J＝8.2,1.9Hz,1H),7.12(d,J＝1.9Hz,1H),7.08(d,J＝5.3Hz,1H),7.04(d,J＝8.2Hz,1H),6.66(d,J＝5.3Hz,1H),1.92–1.81(m,4H),1.22(s,24H),0.86(t,J＝6.9Hz,6H).

1.6 Synthesis of Compound 8

Compound 7(0.81mmol,0.40g) was charged into a 100mL single-neck flask, dissolved in 30mL1, 2-dichloroethane, magnetically stirred, and added with N, N-dimethylformamide (6.51mmol,0.78mL), phosphorus oxychloride (6.51mmol,0.60mL) under ice-water bath conditions for reaction for 5min, and stirred at room temperature for 12 h. The reaction was quenched with water, the reaction mixture was poured into 90mL of water, extracted with petroleum ether (3X 30mL), and the light yellow organic phase was collected and washed with saturated potassium carbonate solution (3X 45 mL). Collecting organic phase, drying with anhydrous magnesium sulfate, distilling under reduced pressure to remove organic solvent, vacuum drying, and separating the residue with petroleum ether/dichloromethane mixed solvent (v: v,8:1) as eluent by column chromatography to obtain compound 8(360.00mg, 86% yield) as orange viscous liquid.¹H NMR(400MHz,CDCl₃)δ9.81(s,1H),7.41(d,J＝8.1Hz,1H),7.30(s,1H),7.20(d,J＝8.2Hz,1H),7.18(s,1H),1.87(dd,J＝12.4,7.9Hz,4H),1.24(d,J＝19.3Hz,24H),0.86(t,J＝6.7Hz,6H).

1.7 Synthesis of Compound 10

Placing compound 9(0.75mmol,0.30g) in a 100mL dry three-necked flask, adding 20mL dry n-hexane, and magneticallyStirring to dissolve, dropwise adding n-butyllithium n-hexane solution (2.5M,0.34mL) at-78 ℃ under the protection of nitrogen, reacting for 0.5h, adding trimethyltin chloride (1M,0.86mL), continuing to react for 0.5h at-78 ℃, and heating to room temperature again to react for 12 h. The reaction mixture was poured into 90mL of water, extracted with petroleum ether (3X 30mL), and the light yellow organic phase was collected, followed by washing the organic phase with saturated potassium carbonate solution (3X 45 mL). The organic phase was collected, dried over anhydrous magnesium sulfate, and then the organic solvent was distilled off under reduced pressure and dried under vacuum to obtain compound 10(0.41g, yield 97%) as a gray liquid.¹H NMR(400MHz,CDCl₃)δ7.07(d,J＝4.8Hz,1H),6.95–6.89(m,2H),1.86(d,J＝4.0Hz,4H),1.00–0.86(m,15H),0.76–0.72(m,6H),0.59(dd,J＝6.8,2.8Hz,8H),0.39(d,J＝27.5Hz,9H).

1.8 Synthesis of Compound 11

Compound 10(0.37mmol,0.21g), compound 8(0.35 mmol,0.18 g), tetrakis (triphenylphosphine) palladium were sequentially added to a 50mL single-neck flask, dissolved in 20mL toluene, magnetically stirred, heated to 110 ℃ under nitrogen, reacted for 12h, and cooled to room temperature. The organic solvent was removed by distillation under the reduced pressure, and the residue was subjected to column chromatography using a mixed solvent of petroleum ether and dichloromethane (v: v,6:1) as an eluent to give compound 11(0.26g, yield 84%) as a yellow viscous liquid.¹H NMR(500MHz,CDCl₃)δ9.80(s,1H),7.51–7.48(m,1H),7.33(d,J＝8.0Hz,1H),7.30(s,1H),7.21(s,1H),7.18(s,1H),7.17(d,J＝4.9Hz,1H),6.96–6.93(m,1H),1.97(dd,J＝22.3,20.4Hz,4H),1.88(s,4H),1.27–1.20(m,24H),0.95(dd,J＝31.9,16.0Hz,16H),0.84(t,J＝6.8Hz,6H),0.75(d,J＝6.0Hz,3H),0.68(d,J＝2.4Hz,3H),0.65–0.58(m,8H).

1.9 Synthesis of Compound 12

Compound 11(0.12mmol,0.40g) was charged into a 50mL single-neck flask, dissolved in 15mL1, 2-dichloroethane, magnetically stirred, and added with N, N-dimethylformamide (1.14mmol,0.83mg), phosphorus oxychloride (1.14mmol,0.18mg) in an ice-water bath to react for 5min, and stirred at room temperature for 12 h. The reaction was quenched with water, the reaction mixture was poured into 90mL of water, extracted with petroleum ether (3X 30mL), and the light yellow organic phase was collected and washed with saturated potassium carbonate solution (3X 45 mL). Collecting the organic phase, anhydrous sulfuric acidAfter drying magnesium, the organic solvent was distilled off under reduced pressure, vacuum dried, and the residue was subjected to column chromatography using a mixed solvent of petroleum ether and dichloromethane (v: v,3:1) as an eluent to give compound 12(0.09g, yield 86%) as an orange-yellow viscous liquid.¹H NMR(400MHz,CDCl₃)δ9.85(s,1H),9.82(s,1H),7.59(d,J＝3.9Hz,1H),7.54(dd,J＝6.1,2.0Hz,1H),7.37(d,J＝8.0Hz,1H),7.32(s,1H),7.24(s,1H),7.23(s,1H),1.99(d,J＝14.0Hz,8H),1.24(d,J＝11.6Hz,24H),0.95(d,J＝26.4Hz,16H),0.84(d,J＝6.9Hz,6H),0.75(s,3H),0.68(d,J＝4.7Hz,3H),0.63(t,J＝7.3Hz,8H).

1.10 Synthesis of CPDT-TiC-2DFCN

Compound 12(0.092mmol,0.08g), compound 13(0.37 mmol, 0.10g), 20mL tetrahydrofuran were added to a 50mL single-neck flask, dissolved by magnetic stirring, 0.20mL pyridine was injected under nitrogen, heated to 60 deg.C, reacted for 4h, and cooled to room temperature. The organic solvent was removed by distillation under the reduced pressure, and the black solid CPDT-TiC-2DFCN (0.07g, 59% yield) was obtained by settling.¹H NMR(500MHz,CDCl₃)δ8.91(s,1H),8.77(s,1H),8.54(dd,J＝16.6,6.8Hz,2H),7.75–7.64(m,3H),7.60(t,J＝8.6Hz,2H),7.50(s,1H),7.33(s,1H),7.31(s,1H),2.00(s,8H),1.24(d,J＝11.6Hz,24H),0.98(dd,J＝20.2,13.6Hz,16H),0.85(t,J＝6.8Hz,6H),0.73(dt,J＝10.3,6.4Hz,8H),0.65(dt,J＝11.7,5.8Hz,6H).

Example 2

And (3) synthesizing an asymmetric A-D-D' -A type micromolecule receptor material CPDT-TiC-2DClCN based on the thieno-isochroman unit.

The synthetic route of CPDT-TiC-2DClCN is as follows:

compound 12(0.058mmol,0.05g), compound 14(0.23mml,0.61g), 10mL tetrahydrofuran were added to a 50mL single-necked flask, stirred magnetically, charged with 0.10mL pyridine under nitrogen, heated to 65 deg.C, reacted for 4h, and cooled to room temperature. The organic solvent was removed by distillation under the reduced pressure, and the black solid CPDT-TiC-2DClCN (0.04g, 51% yield) was obtained by settling.¹H NMR(400MHz,CDCl₃)δ8.94(s,1H),8.78(d,J＝4.0Hz,2H),8.76(s,1H),7.96(s,1H),7.93(s,1H),7.61(t,J＝6.4Hz,3H),7.50(s,1H),7.34(s,1H),7.31(s,1H),2.01(d,J＝4.1Hz,8H),1.23(s,24H),1.06–0.98(m,12H),0.94(s,4H),0.84(d,J＝7.0Hz,6H),0.75(s,4H),0.71(s,4H),0.66(d,J＝7.2Hz,6H).

Example 3

The performance characterization of small molecule acceptor materials CPDT-TiC-2DFCN and CPDT-TiC-2DClCN and the preparation and test of a photovoltaic device.

¹The H NMR spectrum was determined by means of a Bruker Dex-400 NMR instrument, the UV-Vis absorption spectrum by means of a Shimadzu UV-2600 UV-Vis spectrophotometer, and the cyclic voltammogram was measured with a CHI630E electrochemical analyzer.

The organic solar cell device based on the micromolecular acceptor material comprises an Indium Tin Oxide (ITO) conductive glass anode, a cathode modification layer, an optical activity layer, an anode modification layer and a cathode. The active layer material is the asymmetric A-D-D' -A type micromolecule receptor material and a commercially available polymer donor material, and the blending weight ratio of the active layer material to the commercially available polymer donor material is 1.2: 1.

3.1 determination of light absorption Properties of organic Small molecule acceptor materials CPDT-TiC-2DFCN and CPDT-TiC-2DClCN

FIG. 1 shows UV-visible absorption spectra of organic small molecule acceptor materials CPDT-TiC-2DFCN and CPDT-TiC-2DClCN in chloroform solution and film states, which show that they have wide and strong absorption in both solution and film, and exhibit two distinct characteristic absorption peaks in the range of 350-900nm, short band absorption is attributed to the transition of pi-pi of the main chain of the molecule, and long band absorption is attributed to the charge transfer (ICT) action from donor unit to acceptor unit in the molecule. The film showed a significant red shift with respect to the absorption of the solution and a vibration shoulder appeared, which is due to the increased molecular packing in the solid state. By calculation, the optical band gaps of CPDT-TiC-2DFCN and CPDT-TiC-2DClCN are respectively 1.48eV and 1.46eV (the formula is that Eg is 1240/lambda, wherein Eg is the optical band gap and lambda is the maximum absorption side band value of the film).

3.2 electrochemical Performance determination of organic Small molecule acceptor materials CPDT-TiC-2DFCN and CPDT-TiC-2DClCN

The cyclic voltammograms of organic micromolecule acceptor materials CPDT-TiC-2DFCN and CPDT-TiC-2DClCN in the solid film are shown in figure 2 according to a calculation formula E_HOMO＝-(E_ox+4.80) eV, giving them HOMO levels of-5.61 eV and-5.68 eV, respectively. According to the calculation formula E_LUMO＝-(E_red+4.80) eV, giving them LUMO levels of-4.10 eV and-4.01 eV, respectively. The electrochemical band gaps of CPDT-TiC-2DFCN and CPDT-TiC-2DClCN are calculated to be 1.51eV and 1.67eV respectively.

3.3 determination of photovoltaic Properties of organic Small molecule acceptor materials CPDT-TiC-2DFCN and CPDT-TiC-2DClCN

The organic solar cell device was prepared by using commercially available PM6 as an active layer donor material for an organic solar cell, CPDT-TiC-2DFCN and CPDT-TiC-2DClCN synthesized in examples 1 and 2 as active layer acceptor materials, respectively, and using bulk heterojunction formal device structures ITO/PEDOT: PSS (23nm)/PM6: CPDT-TiC-2DFCN (1:1.2 w/w; CF, 0.50% CN,2750r.p.,91nm)/PDINO (5nm)/Ag (100nm) or ITO/PEDOT: PSS (23nm)/PM6: CPDT-TiC-2DClCN (1:1 w/w; CF, 0.50% CN, 0r.p.m,93nm)/PDINO (5nm)/Ag (100 nm). In a simulated sunlight light source (the light intensity is 100 mW/cm)²) The J-V curve of the organic solar cell was measured under illumination, as shown in fig. 3, with the test results: short-circuit current J of organic solar cell device based on PM6: CPDT-TiC-2DFCN_scIs 17.90mA/cm²Open circuit voltage V_oc0.86V and a fill factor FF of 64.67%, from which the energy conversion efficiency PCE of the cell was calculated to be 10.01%; organic solar cell device short-circuit current J based on PM6: CPDT-TiC-2DClCN_scIs 18.77mA/cm²Open circuit voltage V_ocAt 0.86V and a fill factor FF of 63.30%, the energy conversion efficiency PCE of the cell was calculated to be 10.20%.

Under the optimal condition, the EQE curves of the PM6, the CPDT-TiC-2DFCN and the PM6, the CPDT-TiC-2DClCN are shown in a figure 4, the figure shows that the EQE test ranges of the active layers corresponding to the two small molecule receptors are both 300-900nm, wherein the external quantum efficiency of the PM6, the CPDT-TiC-2DFCN exceeds 50% in the range of 420-790nm, and the maximum EQE value reaches 71% at the position of 690nm or so; and the external quantum efficiency of PM6: CPDT-TiC-2DClCN exceeds 50% in the range of 450-790nm, and the maximum EQE value appears around 560nm and reaches 74%.

While the present invention has been described in connection with the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. In light of the present inventive concept, those skilled in the art will recognize that certain changes may be made in the embodiments of the invention to which the invention pertains without departing from the spirit and scope of the claims.