Highly Emissive Organic Single-Molecule White Emitters by Engineering o-Carborane-Based Luminophores

Article abstract of DOI:10.1002/anie.201703862

The development of organic single-molecule solid-state white emitters holds a great promise for advanced lighting and display applications. Highly emissive single-molecule white emitters were achieved by the design and synthesis of a series of o-carborane-based luminophores. These luminophores are able to induce multiple emissions to directly emit high-purity white light in solid state. By tuning both molecular and aggregate structures, a significantly improved white-light efficiency has been realized (absolute quantum yield 67 %), which is the highest value among the known organic single-molecule white emitters in the solid state. The fine-tuning of the packing modes from H- to J- and cross-stacking aggregates as well as intermolecular hydrogen bonds are successful in one molecular skeleton. These are crucial for highly emissive white-light emission in the solid state.

Full text of DOI:10.1002/anie.201703862

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Accepted Article
Title: Highly-Emissive Organic Single-Molecule White Emitters by
Engineering o-Carborane-based Luminophores
Authors: Hong Yan, Deshuang Tu, Pakkin Leong, Song Guo,
Changsheng Lu, and Qiang Zhao
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COMMUNICATION
Highly-Emissive Organic Single-Molecule White Emitters by
Engineering o-Carborane-based Luminophores
[a]
[a]
[b]
[a]
[a]
[b]
Deshuang Tu, Pakkin Leong, Song Guo, Hong Yan,* Changsheng Lu* and Qiang Zhao*
Abstract: The development of organic single-molecule solid-state
white emitters holds a great promise for advanced lighting and
display applications. Here we report a novel molecular engineering
for highly-emissive single-molecule white emitters by design and
synthesis of a series of o-carborane-based luminophores. These
luminophores are able to induce multiple emissions to directly emit
high-purity white light in solid state. By tuning both molecular and
aggregate structures, a significantly improved white-light efficiency
has been realized (absolute quantum yield 67%), which is the
highest value among the known organic single-molecule white
emitters in solid state. The fine-tuning of the packing modes from H-
to J- and Cross-stacking aggregate as well as intermolecular
hydrogen bonds are successful in one molecular skeleton. These
are crucial for highly-emissive white-light emission in solid state.
o-carboranyl unit, multiple emissions from both charge transfer
(CT) and locally-excited (LE) state, might be generated for o-
carborane-based luminophores. Moreover, the o-carborane
cage offers functionalizable positions with which both molecular
structures and crystal packing structures might be tuned. All the
characteristics of o-carborane motivates us to initiate a novel
molecular engineering for highly emissive single-molecule white
emitters.
Based on above strategy, in this work, a new class of o-
carborane-based luminophores with a D−π−A structure was
designed and synthesized (Scheme 1). Through the optimization
of the π-conjugated donors, o-carborane-based phenanthrene,
1-ph (Scheme 1), is capable of inducing dual emissions from
both LE and CT state in solid state to give rise to
complementary-color white light with
a CIE (Commission
Internationale de l’Eclairage) coordinate of (0.33, 0.36) and an
absolute quantum efficiency of 46%. Through further fine-
tailoring the molecular structure of 1-ph by suitable substituents
Upon growing need in the advanced lighting and display
applications, organic white-light devices have received
[
1]
increasing attentions. As white light covers the whole visible
region ranging from 400 to 700 nm, white-light devices are
usually fabricated by the incorporation of multicomponent
emitters which exhibit three primary or two complementary
(
Scheme 2), both the crystal packing structures and
intermolecular hydrogen bonds can be tuned to lead to
significantly improved white-light luminous efficiency of 67% (3f
in Scheme 2). To the best of our knowledge, this is the highest
value among the single-molecule white-light emitters in solid
[2]
colors of light. This approach, however, encouters many thorny
problems, such as spectral instability, bad color reproducibility
[3,4]
state.
[
3]
and fabrication complexity. The best strategy to solve these
problems is to develop single-molecule white emitters. To date,
however, few strategies enable single-molecule luminophores to
[
4]
emit white light efficiently in solid state. Two crucial issues
have determined such slow research progress. On one hand, to
achieve white-light emission requires precise manipulation of
excited state of emitters through a rational molecular design,
which is very difficult to realize. On the other hand, restricted by
[
5]
both the broad band gap
and the aggregation-caused
[
6]
quenching (ACQ) effect, the luminous efficiency in solid state
is usually low. Therefore, the design of a highly-emissive solid-
state white emitter still remains a big challenge.
To realize a single-molecule white emitter, herein, a new-type
molecular design strategy of multiple emissions from tailorable
o-carborane-based luminophores was proposed (Scheme 1).
The unique o-carborane bears multiple properties including
three-dimentional pseudo cage structure and dual electronic
[
7]
effects, and has proven to be a promising building block for
[8 9]
photofunctional materials. , However, highly efficient white-light
emission in solid state by one single carborane-based organic
molecule has not been reported. As an electronic acceptor of the
Scheme 1. The design strategy for single-molecule white emitters.
[
a]
b]
D. Tu, P. Leong, Prof. Dr. H. Yan
State Key Laboratory of Coordination Chemistry
Nanjing University, Nanjing 210023 (China)
E-mail: hyan1965@nju.edu.cn; luchsh@nju.edu.cn;
The o-carborane-based luminophores were synthesized
through a Suzuki coupling reaction in yields of 41−61% (Scheme
[
S. Guo, Prof. Dr. Q. Zhao
Key Laboratory for Organic Electronics and Information Displays and
Institute of Advanced Materials
Nanjing University of Posts and Telecommunications
Nanjing 210023 (China)
E-mail: iamqzhao@njupt.edu.cn
1
13
11
S1). Their structures were firmly identified by H, C, B NMR
and MS (see Supporting Information). Moreover, the crystal
structures of all the o-carborane-based compounds were solved
(
Figure S1). Owing to the bulkiness of the o-carboranyl unit, in
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COMMUNICATION
general, no intermolecular
packing diagrams (Figure S2). As a result, ACQ effect could be
suppressed.
To examine whether the o-carboranyl unit can induce multiple
emissions for the designed molecules shown in Scheme 1, the
photophysical properties of all compounds were investigated.
The absorption spectra display bathochromic shifts in contrast to
the corresponding o-carborane-free model compounds (Figure
S4), demonstrating the participation of the o-carboranyl unit in
π
···
π
interaction was observed in the
S6 and S7) in spite of the presence of good electronic
communication between o-carboranyl and the donor unit (Figure
1b). It might be the easy intramolecular rotation of the donor
[
12]
units that disrupts the radiative transition from CT state. The
DFT calculations (Figure S15) show the rotation barrier (Erb) of
6.29 eV for 1-an, 2.26 eV for 1-ph and 1.75 eV for 1-na. The
lower Erb for the later two indicates more active intramolecular
[6]
rotation, thus inhibiting CT emission. To further confirm, the
low temperature (77 K) PL spectra of 1-na, 1-ph and their
corresponding o-carborane-free control compounds in THF were
measured (Figures 1c and S8). As a result, a weak broad
emission band around 500-700 nm could be observed only for 1-
na and 1-ph. This demonstrates that the intramolecular CT state
can be generated by the introduction of o-carborane, but
inhibited in solution for 1-na and 1-ph owing to the ready
rotation of the donor unit.
[
10]
an extended π-conjugation. In addition, both the o-carborane-
based luminophores and the corresponding model compounds
feature similar photoluminescence (PL) spectra in CH
2 2
Cl
(
Figure S5), but the former are nearly non-emissive (φ < 0.06,
f
Table S3). This is ascribed to the variable C–C bond in the o-
carboranyl unit which is involved in the excited state to dissipate
[
11]
energy. In order to gain in-depth insight into this phenomenon,
the time-dependent density functional theory (TD-DFT)
calculations were performed. The highest occupied molecular
orbitals (HOMO) of these compounds locate in the donor units
Furthermore, the PL spectra in the crystalline state were
studied (Figures 1d and S9). To our delight, 1-ph was the sole
compound to display white-light emission with a CIE coordinate
(0.33, 0.36) because of the balanced blue and red emissions
(Figure 1d). To explore the origin of the white-light emission,
other aggregation-state photophysical properties were measured.
For example, 1-ph exhibits evident aggregation-induced
emission (AIE) behavior (Figure S10) in contrast to 9-
phenylphenanthrene (2-ph) owing to restricted intramolecular
(
e.g. triphenylamine in 1-tpa), whereas the lowest unoccupied
molecular orbitals (LUMO) are distributed on the o-carboranyl
unit (Figure S14). Particularly, both the charge change (such as
41.6% for 1-tpa, Table S6) and the bond length variation (e.g.
∆(C−C)S1-S0 = 0.79 Å in 1-tpa, Table S7) for the C−C bond of the
o-carboranyl unit can be observed during emission process. This
adequately indicates that the C−C bond variation leads to a
nonradiative decay from the excited state.
[6b]
motion in aggregation state.
With water fraction over 80%,
dual emissions were observed. The blue emission, similar to
that of 2-ph, arises from the LE state of phenanthrenyl unit. The
broad emission around 580 nm, corresponding to the low
temperature (77 K) PL spectrum in solution, is attributed to CT
emission. Moreover, if doped into polyvinylpyrrolidone (K90), 1-
ph also exhibits dual emissions (Figure S11). However, the
absolute quantum efficiency (φabs) of 1-ph in crystals (46%,
Table 1) is superior to those of powder (22%) and doped
samples (18-22%, Table S4). Thus 1-ph possesses CIEE
[
13]
(
crystallization-induced emission enhancement) property. The
wide-angle X-ray diffraction measurement for a powder sample
presents considerably decreased peak intensity and increased
peak widths (Figure S12), implying that ordered molecular
packing has been destroyed. In sharp contrast, the crystal
structure of 1-ph shows a H-aggregate via intermolecular
C
cage−H···
π
interaction (2.814 Å) between the o-carboranyl and
the phenanthrenyl units (Figure 1d). This effectively avoids the
··· stacking of phenanthrenyl units, thus giving bright white-
Figure 1. a) The PL spectra of o-carborane-based luminophores in toluene,
inset: luminescence photographs; b) The calculated HOMO and LUMO
distributions of 1-ph and 1-na in the excited state; c) PL spectra of 1-ph in
THF at 293 K and 77 K; d) PL spectrum of 1-ph in crystalline state, inset: CIE
coordinate, luminescence photographs and the packing structures of 1-ph.
π
π
light emission in solid state.
Even having an acceptable white-light emitter 1-ph in hand,
both the H-aggregate and the rotatable spherical shape of the o-
carborane cage (Figure 1d) are not beneficial for φabs
[14]
.
We
assumed that such a packing structure might be changed via
regulating the molecular structure of 1-ph by substitution at the
Next, the PL spectra of all compounds in n-hexane and
toluene were investigated (Figures S6 and S7). Only 1-tpa, 1-an,
o-carboranyl unit or the phenyl linker. Thus
a series of
derivatives of 1-ph were synthesized (Scheme 2, Figure S1).
Indeed, the molecular packing modes can be tuned from H-
aggregate (1-ph, 3-me, 3-ph, 3-cl and 3-f) to J-aggregate (3-pr)
and Cross-stacking aggregate (3-ph-me) (Scheme 2).
Compounds 3-f, 3-ph-me and 3-cl still exhibit white-light
emission in crystalline state (Table 1, Figures 2a and S13).
Unexpectedly, the bluish-green emission was observed for 3-ph,
1-py and 1-cz show the similar multiple emissions (Figure 1a).
The emissions around 380-500 nm arise from the LE states of
the donor units, and the broad emissions around 500-700 nm
are ascribed to the CT emissions from the donor units to the o-
[
9b]
carboranyl
unit.
These
assignments
were
further
substantiated by TD-DFT calculations (Figure S14). In sharp
contrast, 1-ph and 1-na exhibit only LE state emission (Figures
3-me and 3-pr (Figure 2b, Table 1). The TD-DFT calculations
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reveal that 3-f, 3-ph-me and 3-cl display the similar distributions
of HOMO and LUMO as in 1-ph (Figure S16a). The introduction
of different substituents at the phenyl linker does not alter the
orbital distributions. Hence, both the CT state and LE state are
present, showing white-light emission. However, the HOMO of
the single crystal structures were carefully investigated (Figures
1d, S2k, S2l and Scheme 2). In 3-f, both stronger Ccage−H···F
[
16]
(2.126 Å) and Bcage−H···π
(2.683 Å) interactions are present,
whereas in 3-cl the Ccage−H···Cl and Bcage−H···π hydrogen
bonds are no longer formed, and the sole Ccage−H···π interaction
(3.291 Å) is extremely weak. In 1-ph, the only Ccage−H···π (2.814
Å) exsits. We suggest that these intermolecular hydrogen bonds
can restrict the rotation of the o-carboranyl cage which is closely
related to φabs. To confirm, the TD-DFT calculations were used
to optimize the molecular structures at different rotation angles
of the o-carboranyl unit (20°) (Figure S17). The compounds also
show a large C−C bond variation (up to 0.73 Å) in the o-
carboranyl unit during LUMO→HOMO transition, which implies
3-me, 3-pr and 3-ph locates in the phenanthrenyl unit, whereas
the LUMO centers on the o-carboranyl unit, reflecting different
electron-density populations in comparison to 1-ph (Figure
S16b). In this case, hence, only CT state is formed, giving rise to
a broad bluish-green emission.
[
11]
the deactivation pathway from the excited state.
The
calculations reveal the stronger intermolecular noncovalent
interactions around the o-carboranyl unit in 3-f (Figures 3a and
S18) which lead to a more compact packing structure (voids
0.2%) than 1-ph (voids 0.8%) and 3-cl (voids 1.2%) (Figures 3b
and S3). Moreover, by calculating the energy levels of both the
single molecule and its dimer, the most stable aggregate is also
attributed to 3-f, followed by 1-ph and 3-cl (Figure S19). Hence,
the rotation of the o-carboranyl unit can be efficiently restricted
by the multiple and stronger intermolecular hydrogen bonds in 3-
[17]
f to form a more stable and rigid aggregate structure,
thus
emitting strongest white light among the compounds studied.
Scheme 2. The molecular and packing structures of 1-ph derivatives.
Table 1. Summary of photophysical parameters of o-carborane-based
phenylphenanthrenes.
1-ph
3-f
3-ph-
me
3-cl
3-pr
3-me
3-ph
Colour
CIE
white
white
white
white
bluish-
green
bluish-
green
bluish-
green
(0.33,
(0.29,
0.26)
(0.26,
0.26)
(0.28,
0.36)
(0.17,
0.39)
(0.15,
0.28)
(0.15,
0.30)
0
.36)
φ
abs
46%
67%
50%
17%
98%
70%
10%
Surprisingly, the φabs of these compounds in crystalline state
are of significant difference (Table 1), dependent on aggregate
structures. In the case of the bluish-green emitters, 3-pr shows
excellent φabs (98%), much higher than those of 3-me (70%) and
3
-ph (10%). This proves that J-aggregate facilitates
abs
φ ,
Figure 2. a,b) The solid-state PL spectra of 1-ph derivatives shown in Scheme
2, inset: CIE coordinates, φabs and luminescence photographs; c) Splitting of
the optically allowed transitions of H-, J- and Cross-stacking aggregate.
whereas the dipole-forbidden nature of H-aggregate determines
[
14]
a lower φabs (Figure 2c). The uniform H-aggregate alignment
in 3-ph even leads to the lowest luminous efficiency (Figure S2j).
For the white emitters, the φabs of 3-f has reached 67%, higher
than the known organic single-molecule white emitters (i.e., the
reported largest φabs = 47%).
and 17%, respectively. 3-ph-me adopts
aggregate which also promotes φabs owing to a progressive
We also explored the potential applications of these white-light
emitters by taking 1-ph as an example. The thermogravimetric
analysis shows high thermal stability with decomposition at 359
[3,4]
3-ph-me and 3-cl afford 50%
a
Cross-stacking
o
o
C, over 100
C higher than the carborane-free control
[
15]
transition from the lowest excited state (Figure 2c).
compound (2-ph) (Figure S20). Obviously, it is the introduction
of o-carborane that improves the thermal stability of the organic
luminophores. To utilize the efficient white-emissive property of
We note that the similar H-aggregate of 3-cl, 1-ph and 3-f
leads to distinct φabs values (Table 1). To better understand this,
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1-ph, a white-emitting device was fabricated as shown in
Key words: carborane • white light • organic luminophore •
Supporting Information. The device presents a pure and bright
white light with CIE coordinates (0.33, 0.36) (Figure 3c). The
aggregation induced emission • hydrogen bonds
4
-2
white-light brightness can reach 1.4 × 10 cd m under a low
operating voltage (4.0 V) (Figure S21), far beyond practical use
[1]
[2]
[3]
a) Y. Sun, N. C. Giebink, H. Kanno, B. W. Ma, M. E. Thompson, S. R.
Forrest, Nature 2006, 440, 908; b) S. Reineke, F. Lindner, G. Schwartz,
N. Seidler, K. Walzer, B. Lüssem, K. Leo, Nature 2009, 459, 234.
a) L. Ying, C. Ho, H. B. Wu, Y. Cao, W. Y. Wong, Adv. Mater. 2014, 26,
3
-2
(
i.e. 1.0 × 10 cd m ). This may provide promising applications
for future lighting.
2459; b) G. J. Zhou, Q. Wang, X. Z. Wang, C. Ho, W. Y. Wong, D. G.
Ma, L. X. Wang, Z. Y. Lin, J. Mater. Chem. 2010, 20, 7472.
a) R. J. Wang, D. Liu, H. Ren, T. Zhang , H. M. Yin, G. Y. Liu, J. Y. Li,
Adv. Mater. 2011, 23, 2823; b) H. Wei, Z. F. Zhao, C. Wei, G. Yu, Z. W.
Liu, B. Zhang, J. Bian, Z. Q. Bian, C. H. Huang, Adv. Funct. Mater.
2
016, 26, 2085; c) Q. Zhang, D. F. Li, X. Li, P. B. White, J. Mecinović, X.
Ma, H. Ågren, R. J. Nolte, H. Tian, J. Am. Chem. Soc. 2016, 138,
3541.
1
[4]
a) Z. L. Xie, C. Chen, S. D. Xu, J. Li, Y. Zhang, S. W. Liu, J. R. Xu, Z. G.
Chi, Angew. Chem. Int. Ed. 2015, 54, 7181; b) Q. Y. Yang, J. M. Lehn,
Angew. Chem. Int. Ed. 2014, 53, 4572; c) G. M. Farinola, R. Ragni,
Chem. Soc. Rev. 2011, 40, 3467.
[
5]
6]
a) J. V. Caspar, T. J. Meyer, J. Phys. Chem. 1983, 87, 952; b) J. V.
Caspar, E. M. Kober, B. P. Sullivan, T. J. Meyer, J. Am. Chem. Soc.
1982, 104 , 630.
[
a) J. Liang, B. Z. Tang, B. Liu, Chem. Soc. Rev. 2015, 44, 2798; b) J.
Mei, Y. N. Hong, J. W. Y. Lam, A. J. Qin, Y. H. Tang, B. Z. Tang, Adv.
Mater. 2014, 26, 5429.
Figure 3. a) The calculated intermolecular interactions for 3-cl and 3-f, green
indicates noncovalent interactions; b) The voids of the unit cells for 3-f and 3-
cl; c) CIE chromaticity coordinates and PL spectrum of the white LED device
from 1-ph, inset: luminescence photographs.
[7]
a) R. N. Grimes, Carboranes, Academic Press, New York, 3nd, 2016;
b) R. E. Williams, Chem. Rev. 1992, 92, 177; c) A. M. Spokoyny, C. W.
Machan, D. J. Clingerman, M. S. Rosen, M. J. Wiester, R. D. Kennedy,
C. L. Stern, A. A. Sarjeant, C. A. Mirkin, Nat. Chem. 2011, 3, 590.
a) N. S. Hosmane, Boron Science: New Technologies and Applications,
CRC Press, Boca Raton, FL, 2011; b) R. Núñez, I. Romero, F. Teixidor,
C. Viñas, Chem. Soc. Rev. 2016, 45, 5147; c) Grimes, R. N. Dalton
Trans. 2015, 44, 5939; d) R. Visbal, I. Ospino, J. M. López-de-
Luzuriaga, A. Laguna, M. C. Gimeno, J. Am. Chem. Soc. 2013, 135,
[8]
In summary, an efficient strategy for highly emissive organic
single-molecule white emitters has been developed in the o-
carborane-based luminophores. Our results demonstrate that
incorporation of o-carborane to phenanthrene can induce CT
emission and lead to high-purity complementary-color white light
in solid state. For the first time, the new-type intermolecular
hydrogen bonds (Bcage−H···π, Ccage−H···π and Ccage−H···F) from
the o-carborane cage were designed to suppress nonradiative
decay to have realized high-efficiency solid-state white-light
emission (φabs up to 67%) for a simple carborane-phenanthrene
conjugate. Such a φabs is the highest among so far reported
organic single-molecule white-emitters in sold state. In view of
the advantages such as easy preparation, pure white light, high
4
712; e) A. M. Prokhorov, T. Hofbeck, R. Czerwieniec, A. F.
Suleymanova, D. N. Kozhevnikov, H. Yersin, J. Am. Chem. Soc. 2014,
36, 9637; f) J. C. Axtell, K. O. Kirlikovali, P. I. Djurovich, D. Jung, V. T.
1
Nguyen, B. Munekiyo, A. T. Royappa, A. L. Rheingold, A. M. Spokoyny,
J. Am. Chem. Soc. 2016, 138, 15758; g) L. Cerdán, J. Braborec, I.
Garcia-Moreno, A. Costela, M. G. S. Londesborough, Nat. Commun.
2015, 6; h) C. Shi, H. Sun, X. Tang, W. Lv, H. Yan, Q. Zhao, J. Wang,
W. Huang, Angew. Chem. Int. Ed. 2013, 52, 13434.
[9]
a) H. Naito, K. Nishino, Y. Morisaki, K. Tanaka, Y. Chujo, Angew.
Chem .Int. Ed. 2017, 56, 254; b) K. R. Wee, Y. J. Cho, J. K. Song, S. O.
Kang, Angew. Chem. Int. Ed. 2013, 52, 9682.
[10] B. P. Dash, R. Satapathy, E. R. Gaillard, K. M. Norton, J. A. Maguire, N.
φabs and thermal stability, the functionalization of organic
Chug, N. S. Hosmane, Inorg. Chem. 2011, 50, 5485.
luminophores with o-carborane may open a new gateway for
high-performance solid-state light-emitting materials and devices.
[11] Y. H. Lee, J. Park, J. Lee, S. U. Lee, M. H. Lee, J. Am. Chem. Soc.
2015, 137, 8018.
[
[
[
12] Y. Okazawa, K. Kondo, M. Akita, M. Yoshizawa, J. Am. Chem. Soc.
2015, 137, 98.
13] J. Q. Tong, Y. J. Wang, Z. Y. Wang, J. Z. Sun, B. Z. Tang, J. Phys.
Chem. C 2015, 119, 21875.
Experimental Section
14] a) J. Gierschner, S. Y. Park, J. Mater. Chem. C 2013, 1, 5818; b) M.
Kasha, H. R. Rawls, M. El-Bayoumi, Pure and Applied Chemistry 1965,
The synthesis of all compounds was shown in Scheme S1. All
experimental details can be found in the Supporting Information.
11, 371.
[
[
[
15] Z. Xie, B. Yang, F. Li, G. Cheng, L. Liu, G. Yang, H. Xu, L. Ye, M. Hanif,
S. Y. Liu, D. G. Ma, Y. G. Ma, J. Am. Chem. Soc. 2005, 127, 14152.
16] X. Zhang, H. Dai, H. Yan, W. Zou, D. Cremer, J. Am. Chem. Soc. 2016,
Acknowledgements
138, 4334.
17] Y. P. Li, F. Li, H. Y. Zhang, Z. Q. Xie, W. J. Xie, H. Xu, B. Li, F. Z. Shen,
The authors are grateful for the financial support from NSFC
L. Ye, M. Hanif, D. G. Ma, Y. G. Ma, Chem. Commun. 2007, 231.
(
21472086 and 21531004) and MOST (2013CB922101).
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Entry for the Table of Contents (Please choose one layout)
Layout 1:
COMMUNICATION
A novel molecular engineering for
highly-emissive organic single-
molecule white emitters was
Deshuang Tu, Pakkin Leong, Song Guo,
Hong Yan,* Changsheng Lu* and Qiang
Zhao*
developed. Through tailoring the
molecular structures of o-carborane-
based luminophores, crystal packing
modes can be tuned, leading to a
satisfactory white-light luminous
efficiency up to 67%. To the best of
our knowledge, this is the largest
value among the organic single-
molecule white emitters in solid state.
Page No. – Page No.
Highly-Emissive Organic Single-
Molecule White Emitters by
Engineering o-Carborane-based
Luminophores
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