Circularly Polarized Luminescence from Chiral Conjugated Poly

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Circularly Polarized Luminescence from Chiral Conjugated Poly(carbazoleran-acridine)s with Aggregation-Induced Emission and Delayed Fluorescence YUBING HU, Fengyan Song, Zeng Xu, YUJIE TU, Haoke Zhang, QIAN CHENG, Jacky W. Y. Lam, Dongge Ma, and Ben Zhong Tang ACS Appl. Polym. Mater., Just Accepted Manuscript • DOI: 10.1021/acsapm.8b00118 • Publication Date (Web): 07 Jan 2019 Downloaded from http://pubs.acs.org on January 12, 2019

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ACS Applied Polymer Materials

Circularly Polarized Luminescence from Chiral Conjugated

Poly(carbazole-ran-acridine)s

Aggregation-Induced

Emission

and

with

Delayed

Fluorescence Yubing HU,†, ‡ Fengyan Song,†, ‡ Zeng Xu,§Yujie Tu,†, ‡ Haoke Zhang,†, ‡ Qian Cheng,‡ Jacky W. Y. Lam,*,†, ‡ Dongge Ma,*,§and Ben Zhong Tang*,†,‡, § †

HKUST–Shenzhen Research Institute, No. 9 Yuexing 1st RD, South Area, Hi-tech Park,

Nanshan, Shenzhen 518057, China ‡

Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research

Centre for Tissue Restoration and Reconstruction and Institute for Advanced Study, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China §

Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and

Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China KEYWORDS: conjugated polymers, circularly polarized luminescence, aggregation-induced emission, delayed fluorescence, aggregation-induced delayed fluorescence, OLEDs.

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ABSTRACT: Pure organic materials with circularly polarized luminescence (CPL) and delayed fluorescence have gained increasing interest from academic and technological areas. To enhance the solid-state emission and exciton utilization in chiral optoelectronic devices, a synthetic strategy to impart conjugated polymers with CPL and aggregation-induced delayed fluorescence was proposed. Herein, two conjugated macromolecules with electron-donating poly(carbazole-ranacridine) backbones, electron-withdrawing dibenzothiophen-2-yl(phenyl)methanone and chiral alanine moieties were designed and synthesized. Their neat films exhibited strong green emission with quantum yields of 6.7% and 10.3% and delayed fluorescence with lifetime of 1.358 μs and 1.366 μs, respectively. Both Cotton effect and CPL with dissymmetry factor of –2.01 ×10–3 and – 1.39 × 10–3 were determined in the solid state. Such unique conjugated polymers were employed as solution-processed emitting layers in organic light emitting diodes, which displayed maximum brightness of 1477 cd/m2 and maximum current efficiency of 2.52 cd/A.

INTRODUCTION Materials with circularly polarized luminescence (CPL) has emerged as a powerful technique for extensive high-tech applications, such as chiroptical recognition sensors,1-4 noninvasive biomedical diagnosis5,6 and optoelectronic devices.7-13 Compared to non-polarized emission, CPL could be employed to prevent the reflection of ambient light in an energy-saving way and applied in high contrast 3D displays.14,15 Moreover, CPL could preserve its polarization longer after multitudinous environmental scattering than linearly polarized light.16 The traditional generation of CPL has been achieved by separating the non-polarized light by complex and energy-consuming filters, including beam splitters,17 quarter waveplates18 and polarizers.19 Unlike these filters, circularly polarized organic light emitting diodes (OLEDs) offer direct CPL in a portable,

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affordable and flexible manner.16 As a result, developing CPL materials and exploring their application in OLEDs is crucial for scientific and technological breakthroughs in chiral optical and photonic devices.20-22 The phenomenon of aggregation-induced emission (AIE) was discovered by Tang et al in 2001 and has evoked considerable interest due to their potential applications in optoelectrical devices.23,24 Compared to traditional luminophores with aggregation-caused quenching (ACQ), AIE-active luminogens showed enhanced emission in the aggregate and solid state than in dilute solution.25,26 Generally, AIE-active luminogens have highly twisted conformations to suppress strong intermolecular interactions and thus increase the utilization of electro-generated excitons.2729

On the other hand, Adachi and co-workers emerged the field of thermally activated delayed

fluorescence (TADF) to construct high-performance OLEDs from pure organic emitters.30-33 TADF emitters exploit both electro-generated singlet (25%) and triplet (75%) excitons through reverse intersystem crossing (RISC) from the lowest triplet state (T1) to the singlet state (S1) under thermal activation.34 By integrating the advantages and design principles of AIE and delayed fluorescence, materials exhibiting aggregation-induced delayed fluorescence (AIDF) are found promising for fabricating high-performance OLEDs with small efficiency roll-off.35,36 Based on the AIDF concept, some small molecules with efficient solid-state emission has been prepared, while their high molecular counterparts, i.e. polymers are rarely synthesized. π-Conjugated polymers have received remarkable attention due to their cost-effective solutionprocessing synthetic methods to fabricate large-area, light-weight and flexible optoelectronic devices.37-42 Meanwhile, conjugated polymers could be systematically modified by incorporating donor (D) and acceptor (A) moieties into polymer backbones in an alternating fashion.43,44 Among them, the side-chain-type conjugated polymers with delayed fluorescence units as pendants are


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beneficial to facilitate RISC process due to their smaller D−A electronic coupling and efficient separation of the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO).45-48 Furthermore, it is convenient to graft chiral side chains onto the conjugated polymers to introduce CPL features. Meanwhile, AIE-active luminophores are favored to avoid the large efficiency roll-off in optoelectronic devices brought by traditional ACQ-active luminophores such as carbazole.27 The construction of AIE-active luminophores in combination with CPL could incorporate the handedness, another molecular design dimension, to furnish the fluorescence area.49 In this way, it is promising to develop side-chain-type CPL and AIDF-active conjugated polymers with potential application in solution-processed OLEDs with low efficiency roll-off. In our previous work, we reported a series of acridine-based luminogens with AIE and TADF properties, which displayed high performance with negligible current efficiency roll-off in nondoped OLEDs.50 In this work, we succeeded in designing and synthesizing conjugated poly(carbazole-ran-acridine)s with AIDF-active dibenzothiophen-2-yl(phenyl)methanone (DBTPM) and chiral alanine pendants by modified Suzuki coupling. Two polymers with different amounts of monomer units were obtained and their AIE behavior, delayed fluorescence and chiroptical properties were studied. Their neat films showed obvious enhanced emission at 539 nm and 542 nm with quantum yield of 6.7% and 10.3% and delayed fluorescence with lifetime of 1.358 μs and 1.366 μs, respectively. Their AIDF properties with prominent delayed fluorescence and rapid RISC processes were clearly proved. Both polymers showed strong Cotton effect at 310 nm and high dissymmetry factor (glum) value of up to –2.01 × 10–3, which confirmed the efficient chiral induction from the alanine pendants to the carbazole and AIDF units. By using the AIDF-


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active polymers as emitting layers, we fabricated non-doped and doped OLEDs, which exhibited maximum brightness (Lmax) of 1477 cd/m2 and maximum current efficiency (CEmax) of 2.52 cd/A. RESULTS AND DISCUSSION Synthesis and structure characterization. As depicted in Scheme 1, the target polymers were synthesized by microwave-assisted Suzuki coupling polymerizations of diborate-substituted carbazole (M1), dibromo-substituted dimethylacridine and carbazole (M2 and M3) in feed molar ratios of 50:5:45 and 50:10:40 to regulate the AIDF effect on the resulting polymers. According to the feed ratio of M2, the obtained polymers were named as P5 and P10. Monomers M1, M2 and M3 were prepared according to the previous reported synthetic procedures (Scheme S1, Figure S1−S3). Chiral groups were attached to M1 through the esterification reaction to endow the resulting polymers with side-chain chirality. M2 and M3 were designed to inherit AIDF properties and improve the solubility and processability of the resulting polymers. Scheme 1. Synthetic route to chiral poly(carbazole-ran-acridine)s

The weight-average molecular weight (Mw) and polydispersity (PDI) of the polymers determined by gel permeation chromatography were 10100 and 1.70 for P5 and 10200 and 1.72 for P10. P5 and P10 were soluble in common organic solvents, such as dichloromethane (DCM), chloroform, tetrahydrofuran (THF) and chlorobenzene. The thermal stability of P5 and P10 was evaluated by thermogravimetric analysis at a heating rate of 10 °C/min. As shown in Figure S4,


5


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P5 and P10 displayed 5% weight loss (Td) at 285 °C and 293 °C, thanks to their rigid conjugated polymer chains. The glass transition of P5 and P10 was measured to be ~130 °C through differential scanning calorimetry analysis under nitrogen atmosphere. The good solubility and high thermal stability of the polymers were beneficial for the fabrication of solution-processed OLED devices.

Figure 1. (A–D) 1H NMR spectra of (A) M1, (B) M2, (C) M3 and (D) P5 in CDCl3. (E–H) 13C NMR spectra of (E) M1, (F) M2, (G) M3 and (H) P5 in CDCl3. All the obtained monomers and polymers were fully characterized by NMR spectroscopies and their NMR spectra in Figure 1 gave satisfactory data corresponding to their chemical structures. The 1H NMR spectrum of M1 exhibited a typical peak related to the methyl proton (b) resonance of the pinacolatoboron unit at δ 1.39, this peak disappeared in the spectra of P5 and P10, confirming the high efficiency of the polymerization reaction. Meanwhile, the spectra of P5 and P10 displayed carbomethoxyl proton (a) resonance of M1 at δ 3.71−3.67 and the acridine proton (c) resonance of M2 at δ 6.54−6.53. The integrals of these characteristic peaks were utilized to


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calculate the content of AIDF unit in the polymers, which was 4.5% for P5 and 10.5% for P10. Similarly, the

13

C NMR spectra of P5 and P10 showed no peak at δ 82.89 associated with

pinacolatoboron carbon (e) resonance of M1. After polymerization, the peaks related to the dimethyl absorptions of the carbon (f) of M1 at δ 18.31 and δ 17.16 and the peak associated with the methyl carbon (h) resonance of M3 at δ 14.05 all preserved in Figure 1H. However, the carbonyl carbon (g) resonance of M2 at δ 195.33 appeared in the polymer spectra. All these results profoundly proved the success in preparing desirable polymeric structures as shown in Scheme 1. Photophysical properties. The UV–vis absorption, photoluminescence (PL) and quantum yield (QY) of P5 and P10 in THF solutions and spin-coating films were first investigated. In the film state, the UV spectra of P5 and P10 exhibited maximum at around 253 nm and 300 nm due to the absorptions of the carbazole and AIDF units (Figure 2A). The broad and weak absorption between 400 nm and 500 nm could be assigned to the charge-transfer transition of these D–A conjugated polymers. As shown in Figure S5, P5 and P10 displayed weak emission bands at 571 nm with low QY of 2.8% and 3.9% in THF solutions, respectively. In the solid state, P5 and P10 exhibited enhanced emission at 542 nm and 539 nm with higher QY of 6.7% and 10.3%, respectively. The increased QY in the film state indicated the AIE characteristics of P5 and P10. To further investigate the inheritance of AIE feature from the AIDF-active precursors (M2), the emission behaviors of P5 and P10 in THF/water mixtures with different water fractions (fw) were recorded. As shown in Figure 2B and 2C, the weak emission of P5 and P10 in dilute THF solutions was almost quenched after the addition of 10% of water. The emission of P5 and P10 was reactivated at a water fraction (fw) of 60% and enhanced gradually afterwards. The emission intensity at 545 nm of P5 attained its maximum at fw = 80%, which was 3.2–fold higher than that in the THF solution. Similarly, the highest emission intensity at 552 nm of P10 was achieved at fw


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= 90%, which was 2.6–fold higher than that in the THF solution. Compared to the dilute solution state, the emission of P5 and P10 was blue-shifted and enhanced in the aggregate and film state due to the collective effect of twisted intramolecular charge transfer (TICT) and AIE. In other words, the restriction of molecular motions in a less polar and more crowded environment reduced the non-radiative decay of the excited state energy and promoted emission. To clearly demonstrate the TICT property, the solvatochromic effect on the emission spectra of P5 was investigated in toluene, DCM, THF, chloroform, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solutions (Figure S6). The emission maximum of P5 redshifted continuously from 532 nm to 582 nm with the solvent polarity increasing, indicating the charge transfer character of poly(carbazoleran-acridine)s in the excited state.

Figure 2. (A) UV–vis absorption and PL spectra of thin films of P5 and P10. (B and C) PL spectra of (B) P5 and (C) P10 in THF/water mixtures with different water fraction (fw). Excitation wavelength: 350 nm. (D) Temperature-dependent transient decay spectra of thin films of P5 and


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P10. (E and F) Transient decay spectra of (E) P5 and (F) P10 in THF/water mixtures with different water fractions (fw). Excitation wavelength: 375 nm. Inset in (E) and (F): fluorescent photos of (E) P5 in THF solution and THF/water mixture with fw of 80% and (F) P10 in THF solution and THF/water mixture with fw of 90% taken under 365 nm excitation. Polymer concentration: 10–5 M. To explore the delayed fluorescence properties of the polymers, their transient PL decay spectra were investigated in the THF solution, aggregate state and film state. As depicted in Figure 2D, the decay time was evidently prolonged with the temperature increasing from 77 K to 300 K due to the acceleration of the RISC process under thermal activation. At ambient temperature (300 K), P5 and P10 decay in a double-exponential function with a prompt fluorescence lifetime (τprompt) of 16.2 ns and 17.3 ns attributed to the exciton relaxation from S1 to S0, and a delayed fluorescence lifetime (τdelayed) of 1.358 μs and 1.366 μs assigned to the RISC from T1 to S1 followed by the relaxation from S1 to S0, respectively. In addition, the corresponding ratio of delayed fluorescence (Rdelayed) was 64.4% for P5 and 70.6% for P10, respectively. After the calculation shown in Table S1, the RISC rate constant (kRISC) was 2.07 × 106 s–1 for P5 and 2.50 × 106 s–1 for P10. According to the equation as below,51 the neat film of P10 with a higher AIDF content possessed a higher kRISC, which represented its narrower energy gap between the singlet and the triplet excited state (ΔEST). 𝑘𝑅𝐼𝑆𝐶 = A · exp (−

ΔE𝑆𝑇 ) 𝑘𝐵 𝑇

where A is a constant, kB is the Boltzmann constant and T is the temperature. As shown in Figure S7, the polymers demonstrated almost negligible delayed fluorescence in air-equilibrated THF solution with mean fluorescence lifetime of 1.89 ns and 2.25 ns for P5 and P10, respectively. The delayed component was evidently increased after bubbling with N2 for ten


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minutes, indicating the oxygen quenching effect on triplet excitons under air condition. The PL decay spectra of P5 and P10 in THF/water mixtures with fw ≥ 60% were also measured in Figure 2E and 2F. It was evident that both decay lifetime and Rdelayed of P5 and P10 were increased after adding water, which clearly proved their AIDF characteristics. This phenomenon was probably because their twisted molecular conformations were restricted upon aggregation formation, which induced more efficient separation of HOMO and LUMO to facilitate the RISC process.27 Electrochemical properties. The redox behaviors of P5 and P10 were measured by cyclic voltammetry (CV) using ferrocene/ferrocenium (Fc/Fc+) as internal standard to evaluate their experimental HOMO and LUMO (Figure S8). The HOMO energy level of P5 and P10 was determined to be –5.15 eV and –5.19 eV, respectively. From the onset wavelength of the absorption spectra shown in Figure S2, the energy gap (Eg) of P5 and P10 was calculated to be 2.76 eV and 2.74 eV. From the equation: LUMO = Eg + HOMO, the LUMO energy level of P5 and P10 was calculated to be –2.39 eV and –2.45 eV, respectively. It demonstrated that the energy levels of the conjugated polymers could be tuned by altering the contents of donors and acceptors. Molecular orbital calculations. Theoretical calculations were processed to obtain the HOMO and LUMO distributions and the ΔEST of the symmetric D-A-D molecular model by density functional theory calculations [DFT, B3LYP/6-31G] to get insight into the AIDF properties of those polymers. As shown in Figure 3, the HOMO of the model compound localized on the electrondonating carbazoles and dimethylacridines while the LUMO located on the electron-withdrawing DBT-PM units. Such a complete electron separation of HOMO and LUMO was probably resulted from the highly-twisted connection of pendant DBT-PM groups with the polymer backbone. Through time-dependent density functional theory calculations [TD-DFT B3LYP/6-311G*], the ∆EST of the D-A-D model between S1 (2.1393 eV) and T1 (2.1342 eV) was calculated to be 0.005


10

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eV (Figure S9). Such a small energy gap ensured the fast RISC process under thermal activation, which provided the theoretical support for the AIDF characters of poly(carbazole-ran-acridine)s.

Figure 3. Frontier molecular orbital distributions for the symmetric D-A-D model of conjugated poly(carbazole-ran-acridine)s calculated by DFT, B3LYP/6-31G. Chiroptical properties. As shown in Figure 4, circular dichroism (CD) spectra and CPL spectra of the spin-coating polymer films were studied to examine the efficiency of chiral induction from the alanine pendants to P5 and P10. In the film state, the polymers demonstrated similar strong Cotton effects with a positive wave at around 258 nm and 310 nm, which were corresponding to their absorption peaks at around 253 nm and 300 nm. Since alanine pendants were CD-inactive at a wavelength longer than 300 nm,52 the CD bands at 310 nm could be attributed to the carbazole and AIDF units. The CD spectra of P5 and P10 in THF solutions and THF/water mixtures with fw of 80% were also investigated in Figure S10, which demonstrated almost no CD signal in the solution state.53 The broad CD band of P5 and P10 in the aggregate and film state between 350 nm and 450 nm could be assigned to the chirality of conjugated polymer backbones, which indicated the successful chirality transfer from alanine moieties to poly(carbazole-ran-acridine)s.


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Figure 4. (A) CD and (B) CPL spectra of P5 and P10 in the film state. ΔI = IL – IR, where IL and IR represented the emission intensity of LCP and RCP. While the CD spectra demonstrated chirality in the ground state, the CPL spectra reflected the differential emission of the luminescent materials upon excitation. To quantitatively evaluate the CPL magnitude, the emission dissymmetry factor (glum = 2(IL – IR)/ (IL + IR)) was employed, where IL and IR represented the emission intensity of the left-handed and right-handed circularly polarized (LCP and RCP) light, respectively. As depicted in Figure 4B, both P5 and P10 exhibited clear CPL signals at around 550 nm associated with the solid-state fluorescence at 539–542 nm. In addition, the negative CPL signal in Figure 4B represented the dominant RCP over LCP. The glum values of P5 and P10 were determined to be –2.01 × 10–3 and –1.39 × 10–3, respectively. Considering that the glum values of organic luminescent materials fell in the range of 10–2−10–6, the glum values of P5 and P10 demonstrated that the chirality of polymers could be efficiently triggered by chiral side chains in the excited state. The glum difference of P5 and P10 might be attributed to the variation of molecular orientation and chiral arrangement due to different contents of DBT-PM units.54,55 OLEDs. Since the poly(carbazole-ran-acridine)s possessed AIDF and chiroptical properties, the potential applications in OLEDs were studied. Eight OLEDs were fabricated with structures of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene:poly(styrenesulfonic acid) (PEDOT:PSS)


12

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(50 nm)/emitting layer (50 nm)/1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB) (45 nm)/LiF (1 nm)/Al by vacuum deposition, where PEDOT:PSS and TmPyPB served as hole- and electrontransporting layers, respectively (Figure 5). The spin-coating neat films of P5 and P10 and their doped films with doping concentration of 5%, 10% and 30% in 4,4'-bis(9H-carbazol-9-yl)biphenyl (CBP) matrix functioned as emitting layers. As a common host material with high triplet energy, CBP could confine triplet excitons within guest emitters to improve the OLED performance. Then, the performances of device 1−8 were investigated and the results were summarized in Figure 6, Figure S11 and S12 and Table 1.

Figure 5. Energy level diagram and chemical structures of device 1−8: ITO/PEDOT:PSS (50 nm)/emitting layer (50 nm)/TmPyPB (45 nm)/LiF (1 nm)/Al. The electroluminescence (EL) spectra of P5 and P10 were peaked at 528–571 nm and resembled their PL spectra in the solid state (Figure 6A and 6C). This suggested that they all originated from the same radiative decay process of photon-excited P5 and P10. The EL spectra showed negligible change even when the driving voltages varied from 8 to 13 V, indicating the high spectral stability of device 1−8. The current density–voltage–luminance (J–V–L) characteristics of the EL devices were shown in Figure 6B and 6D. Compared to device 1−4 based on P5, device 5−8 based on P10 exhibited a relatively lower turn-on voltage (Von) in the range of 6.0−6.8 V, indicating that devices based on P10 possessed more efficient carrier injection and


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transportation. The Lmax attained by the P5- and P10-based devices was 965 and 1477 cd/m2, respectively, which was high enough for application in lighting displays (typically 100−1000 cd/m2).

Figure 6. (A and C) EL spectra of (A) device 2 based on P5 and (C) device 5 based on P10 at different voltages. (B and D) Luminance–voltage–current density characteristics of (A) device 1−4 based on P5 and (C) device 5−8 based on P10. The maximum CEmax, power efficiency (PEmax) and external quantum efficiency (EQEmax) and luminance achieved by device 1−8 were summarized in Table 1. Device 5 based on P10 displayed the best device performance and emit green EL with CEmax of 2.52 cd/A, PEmax of 0.94 lm/W and EQEmax of 0.87%. Compared to device 1−4 based on P5, device 5−8 based on P10 possessed better EL performance due to the higher solid-state QY and faster RISC process of P10. As depicted in Figure S12, the smooth efficiency−luminescence curves of device 1−8 demonstrated their small efficiency roll-off. Specifically, the current efficiency of device 7 was 1.09 cd/A at 127 cd/m2 and


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0.98 cd/A at 1077 cd/m2, indicating a current efficiency roll-off of 9.3% in the practical lighting range. Table 1. Device performance of OLEDs based on P5 and P10a Emitting layer

Von (V)

Lmax (cd/m2)

CEmax (cd/A)

PEmax (lm/W)

EQEmax (%)

λmax (nm)

CIE (x, y)

1

5 wt% P5: CBP

7.0

724

1.05

0.35

0.37

529

(0.360, 0.504)

2

10 wt% P5: CBP

8.2

962

1.20

0.35

0.42

532

(0.380, 0.524)

3

30 wt% P5: CBP

7.6

489

0.88

0.28

0.31

536

(0.392, 0.529)

4

Neat P5 film

7.8

223

0.23

0.08

0.09

564

(0.433, 0.518)

5

5 wt% P10: CBP

6.8

1214

2.52

0.94

0.87

528

(0.355, 0.522)

6

10 wt% P10: CBP

6.6

1477

2.04

0.67

0.70

531

(0.369, 0.527)

7

30 wt% P10: CBP

6.6

1311

1.16

0.37

0.40

534

(0.387, 0.533)

8

Neat P10 film

6.0

214

0.23

0.09

0.09

571

(0.453, 0.510)

Device

a

Abbreviations: Von = turn-on voltage at 1 cd/m2; Lmax = maximum luminescence; CEmax =

maximum current efficiency; PEmax = maximum power efficiency; EQEmax = maximum external quantum efficiency; λmax = electroluminescence maximum; CIE = Commission Internationale de I’Eclairage coordinates. CONCLUSION In this study, two conjugated poly(carbazole-ran-acridine)s with chiral alanine pendants were successfully designed and synthesized to obtain strong CPL and delayed fluorescence in the solid state. The AIE feature embedded the conjugated polymers with strong solid-state emission and the AIDF property promoted fast RISC process with kRISC of up to 2.50 × 106 s–1, which enabled efficient exciton-harvesting ability from the non-radiative T1 states to the radiative S1 states. Theoretical calculations presented the HOMO and LUMO distributions and estimated ΔEST of 0.005 eV for the D-A-D model compound of the polymers. The chirality of the polymers was effectively induced by the chiral side chains either in the ground state or excited state, with glum of up to –2.01 ×10–3 in the film state. Such a synergetic effect of AIE, TADF and CPL could generate


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efficient green-emissive OLEDs with Lmax of 1477 cd/m2 and CEmax of 2.52 cd/A. Although the device performance was moderate among the reported polymeric emitters, we believed that these results could offer a simple and convenient design strategy to achieve AIDF polymers with CPL and explore their application in solution-processed OLEDs. ASSOCIATED CONTENT Supporting Information The supporting information is accessible free of charge in the ACS Publication website in DOI: Synthesis and structure characterization of intermediates, monomers and polymers, TGA and DSC curves, UV–vis and PL spectra, photophysical properties, CV curve and OLED performance. AUTHOR INFORMATION Corresponding Author *(J.W.Y.L.) E–mail: [email protected]. *(D.G.M.) E–mail: [email protected]. *(B.Z.T.) E–mail: [email protected]. Author Contributions Y.H and F.S. contributed equally. Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS This work was financially supported by the National Science Foundation of China (21788102, 21490570, 21490574 and 51508242), the Research Grant Council of Hong Kong (16308116, 16303815, C2014–15G, C6009–17G and A–HKUST605/16), the Science and Technology Plan of Shenzhen (JCYJ20160229205601482, JCY20170307173739739 and JCYJ20170818113602462),


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Table of Contents

Circularly Polarized Luminescence from Chiral Conjugated

Poly(carbazole-ran-acridine)s

Aggregation-Induced

Emission

and

with

Delayed

Fluorescence Yubing HU,†, ‡ Fengyan Song,†, ‡ Zeng Xu,§Yujie Tu,†, ‡ Haoke Zhang,†, ‡ Qian Cheng,‡ Jacky W. Y. Lam,*,†, ‡ Dongge Ma,*,§and Ben Zhong Tang*,†,‡, §


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Circularly Polarized Luminescence from Chiral Conjugated Poly

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