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Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores
Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores Jialei Liu a,n, Wu Gao b, Xinhou Liu a, Zhen Zhen a a Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China b Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China
art ic l e i nf o
a b s t r a c t
Article history: Received 11 December 2014 Received in revised form 22 December 2014 Accepted 22 December 2014
Organic electro-optic (EO) materials have been widely studied and used in microwave photonic devices, due to their advantages in half-wave voltage, bandwidth, low cost and ease of integration. Nonlinear optical (NLO) chromophores, as the core of organic EO materials, can directly decide the characters of organic EO materials, including large EO activity, long term stability, solubility and optical loss. Auxiliary donors have attracted great attentions in NLO chromophores for their strong electron donating ability and significant isolation effect. This feature article describes the application of auxiliary donor in NLO chromophores, including the EO activities, optical characters, stability, crystal structures and machinability. & 2015 Elsevier B.V. All rights reserved.
Keywords: Functional Electronic materials Organic NLO Chromophore EO coefficient
1. Introduction Organic second-order nonlinear optical materials have been developed greatly in the recent years, due to their potential usage in telecommunications, such as electronic/photonic integrated circuits, phased array radar, terahertz spectroscopy, etc. [1–3]. Electro-optic modulator is an important commercial device for translating ultrafast electrical signals into optical signals for fiber-optic telecommunications. Organic NLO materials have shown us great advantages in the preparation of EO modulators according to its inorganic counterpart of lithium niobate, such as larger EO coefficients, faster intrinsic response times and lower dielectric constants [4–7]. These advantages could greatly improve the devices' characters in half-wave voltage, bandwidth and sensitivity. However, for practical application, some key problems of these materials, such as large first order hyperpolarizability of the chromophores and the adverse strong inter-molecular electrostatic interaction among the chromophores molecules, are also needed to be resolved [8,9]. These problems decide the EO coefficients, machinability, long term stability and optical loss directly. Recently, auxiliary donors which could both improve the first order hyperpolarizability and reduce the inter-molecular electrostatic interaction of the NLO chromophores have been reported. According to the
n
Corresponding author. Tel./fax:861082543529. E-mail address: [email protected] (J. Liu).
strong contribution in improving the EO coefficients and solubility, the design and preparation of NLO chromophores with auxiliary donor would become an important research direction in organic NLO materials. Else, such kind of materials may serve as effective space homogeneity of the chromophores as optical triggers [10,11]. 2. Auxiliary donors and their advantages in improving the first order hyperpolarizability of NLO chromophore In the first days, auxiliary electron donor was introduced to the NLO chromophore just for improving the first order hyperpolarizability. Most of the auxiliary donors had well coplanar with the donor, acceptor and electron bridges, which could effectively improve the density and flow capacity of the conjugate electron cloud. Marks, firstly studied the auxiliary donor effects on molecular hyperpolarizabilities by quantitative calculation in 1997. Their results indicated that NLO response properties of such chromophores were more sensitive to the electron excessive of the bridges than to bridge aromaticity; electron-excessive heterocyclic bridges had less tendency to deplete the electron density from the donor groups and thus increase their donor ability; interposing charged five-membered auxiliary donor fragments between strong donor or acceptor groups resulted in large computed second-order NLO response [12]. Chromophore PTCF (in chart 1) containing pyrrole as an auxiliary electron donor was reported by Ma et al.; large molecular hypolarizabilities (β0 ¼1370 10 30 esu) was achieved after the
http://dx.doi.org/10.1016/j.matlet.2014.12.112 0167-577X/& 2015 Elsevier B.V. All rights reserved.
Please cite this article as: Liu J, et al. Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2014.12.112i
2
J. Liu et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
Chart 1. Structure of the NLO chromophore PTCF and DTCF.
pyrrole being introduced to the chromophore [13]. Dihydrobenzothiazolylide was another kind of electron donors widely used in NLO chromophores. In this donor, two rich electron atoms oxygen and nitrogen make it have stronger electron donating ability; the benzocycle structure confirmed its stability and coplanar. Recently, chromophore DTCF was reported with dihydrobenzothiazolylide electron donor and its NLO activity was studied by Hyper-Raleigh scattering. The result showed that chromophore DTCF with a dynamic first hyperpolarizability of 1900 10 30 esu at 800 nm [14].
3. Multifunctional auxiliary donor and their main role in chromophore isolation Due to its aromatic structure and electron mobility, thiophene is widely used in organic semiconductors [15]. Conjugated structure and sulfur atom makes it also possess electron donating ability. NLO chromophore 1 as shown in chart 2 was synthesized by a facile route [16]. In this chromophore, the thiophene ring was designed as a dualfunction structure playing the role of electron donor and providing steric hindrance. Isolated effect is very important in the design of NLO chromophores with large first order hyperpolarizability. Poor isolated effect can't prevent the formation of reverse dipolar chromophore dimers. If the reverse dipolar chromophore dimers formed, the first order hyperpolarizability of the chromophores couldn't convert into the large electro-optic coefficients of the materials [17,18]. As shown in Fig. 1, the chlorohexyloxy group and thiophene ring were on both sides of the conjugated plane, which effectively protected the π-conjugated bridge from an intermolecular Diels–Alder (DA) cycloaddition reaction [19]. The length of the chlorohexyloxy group was close to the distance from electron to acceptor. This arrangement acted to site-isolate the chromophore within the internal free volume created by the chlorohexyloxy group, which was favorable for dipole orientation in poling process. This molecular conformation (the shadow of Fig. 1) effectively isolated the chromophores and weakened the dipole–dipole interactions. The crystal packing data showed ring centroid to ring-centroid separations of 4.9–5.7 Å, which indicated better site isolation than that of the 4.2 Å reported previously [20,21]. The crystal analysis showed that chromophore 1 displayed excellent site-isolation and effectively reduced the intermolecular electrostatic interactions in the EO response. Chromophore 1 was doped into amorphous polycarbonate (APC) with the loading density of 40% for the preparation of EO films. The poled films showed an exceptionally large EO coefficient (r33 ¼337 pm/V at 1310 nm), which confirmed that the microscopic molecular nonlinearity of chromophores could be effectively translated into macroscopic electro-optic properties. This value is exceptionally large compared to those reported (CLD-1: 70–110 pm/V at 1310 nm) for guest-host EO polymers. N,N-diethylaniline was widely used as electron donors in most of the NLO chromophores, due to its strong electron donating ability and stability. Recently, bis(N,N-diethylaniline)unit was introduced to the NLO chromophores as a new donating moiety [22]. Due to its high electron-density and low cost, Bis(N,N-diethylaniline) unit had
Chart 2. Structure of the chromophores 1, 2, 3 and 4.
Fig. 1. Crystal conformation of chromophore 1.
been widely studied in the dye-sensitized solar cells [23–25], but it was rarely used in NLO chromophore before. According to the reasons below, bis(N,N-diethylaniline)unit was chosen as donors to prepare chromophore 3 and 4 in chart 2: 1) N,Ndiethylaniline could improve the electron-donating ability; 2) One of the N,N-diethylaniline unit acted as both the additional donor and the isolated group. Introduction of some isolated groups to chromophore moieties has been proved to be an effective approach to suppress the dipole interactions among chromophores and improve the poling efficiency, thus achieve much larger macroscopic NLO effects [26–29]. These new chromophores with double benzene rings showed an appropriate angle. Such an appropriate angle made the special Y-type structure which was different from the general NLO chromophores with rod-like structure. Fig.2 showed the r33 values of films containing chromophore 3 (film-A), 4 (film-B) and FTC (film-C) with different chromophore loading densities. Traditional chromophore FTC with the single N, N-diethylaniline donor gained the r33 value from 12 pm/V (10 wt%) to 39 pm/V (25 wt%), while the r33 values of chromophore 3 were
Please cite this article as: Liu J, et al. Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2014.12.112i
J. Liu et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
3
roved for several times. Thiophene auxiliary donor which is introduced in the middle of the electron bridge show us r33 values as large as 337 pm/V at 1310 nm; N,N-diethylaniline auxiliary donor is introduced in the same site as the electron donor show us r33 values as large as 149 pm/V at 1310 nm. These results confirm that auxiliary donor can effectively improve the EO activity of organic EO materials and the position of the auxiliary donor is also an important point to maximize the efficiency of auxiliary donors. Else, other auxiliary donors, such as inorganic clusters, will also be an important direction in the future to dissolve the problems in organic NLO material.
Reference
Fig. 2. EO coefficients of NLO thin films as a function of chromophore loading densities.
gradually improved from 30 pm/V (10 wt%) to 149 pm/V (25 wt%). The similar trend of enhancement was also observed for chromophore 4, whose r33 values increased from 50 pm/V (10 wt%) to 143 pm/V (25 wt%). Through the outcome above, we could obviously see that the chromophores with bis(N,N-diethylaniline)unit as donor had nearly 4 times higher r33 value than the chromophore FTC, illustrating that the double donors of the chromophores significantly increased their macroscopic EO activity. X-shaped push–pull chromophore (in chart 2 chromophore 2) was also reported by Dokladalova et al., this kind of chromophore showed us strong charge transfer efficiency. Large NLO character could be estimated from its strong charge transfer efficiency, though it was not reported directly [30]. Janjua introduced polyoxometalates (POMs) as an auxiliary donor; the strong donor ability showed us great tendency in improving the first order hyperpolarizability and the large rigid structure might have great potential in reducing the intermolecular dipole–dipole interaction and improving the long term stability. Unfortunately, it was just a theoretical calculation, and these compounds were also hard to preparation. But the combination of organic group and inorganic group would be a new orientation in the future [31].
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25]
4. Conclusion By the introduction of auxiliary donor, β values of the NLO chromophore are improved and the dipole interaction among the chromophores is also reduced greatly; the EO coefficients are imp-
[26] [27] [28] [29] [30] [31]
Shi Z, Luo J, Huang S, Polishak B, Zhou X. J Mater Chem 2012;22:951. Yao X, Maleki L. J Opt Soc Am B 1996;13:1725–35. Gheorma I, Gopalakrishnan G. IEEE Photon Technol Lett 2007;19:1011. Tkaczyk S., Kityk I., Ebothe J., Viennois R. J. Phys.: Condens. Matter 16 2231. Jungerman R, Johnsen C, McQuate D, Salomaa K, Zurakowski M, Bray R, et al. J Lightwave Technol 1990;8:1363. Elder D, Benight S, Song J, Robinson B, Dalton L. Chem Mater 2014;26:872. Rao S, Coppola G, Gioffre M, Corte F. Opt Express 2012;20:9351. Huang H, Liu J, Zhen Z, Qiu L, Liu X, Lakshminarayana G, et al. Mater Lett 2012;75:233–5. Liu J, Wang L, Zhen Z, Liu X. Colloid Polym Sci 2012;290:1215–20. Adamiv V, Ebothe J, Piasecki M, Burak Y, Teslyuk I, Plucinski K, et al. Opt Mater 2009;31:685–7. Kityk I, Alzayed N, Reshak A, Plucinski K, Berdowski J, Fuks-Janczarek I, et al. Funct Mater Lett 2011;4:357–9. Albert I, Marks T, Ratner M. J Am Chem Soc 1997;119:6575–82. Ma X, Liang R, Yang F, Zhao Z, Zhang A, Song N, et al. J Mater Chem. 2008;18:1756–64. Ashraf M, Teshome A, Kay A, Gainsford G, Bhuiyan M, Asselberghs I, et al. Dyes Pigments 2013;98:82–92. Roncali J. Macromol Rapid Commun 2007;28:1761–75. Wu J, Bo S, Liu J, Zhou T, Xiao H, Qiu L, et al. Chem Commun 2012;48:9637–9. Liu J, Bo S, Liu X, Zhen Z. J Incl Phenom Macrocycl Chem 2010;68:253–60. Hammond S, Clot O, Firestone K, Bale D, Lao D, Haller M, et al. Chem Mater 2008;20:3425–34. Shi Z, Luo J, Huang S, Zhou X, Kim T, Cheng Y, et al. Chem Mater 2008;20:6372–7. Kwon O, Kwon S, Jazbinsek M, Choubey A, Gramlich V, Gunter P. Adv Funct Mater 2007;17:1750–6. Liao Y, Eichinger B, Firestone K, Haller M, Luo J, Kaminsky W, et al. J Am Chem Soc 2005;127:2758–66. Yang Y, Xu H, Liu F, Wang H, Deng G, Si P, et al. J Mater Chem C 2014;2:5124. Tang K, Liang M, Liu Y, Sun Z, Xue S. Chin J Chem 2011;29:89–96. Dumur F, Mayer CR, Dumas E, Miomandre F, Frigoli M, Secheresse F. Org Lett 2008;10:321–4. Kitamura T, Ikeda M, Shigaki K, Inoue T, Anderson N, Ai X, et al. Chem Mater 2004;16:1806–12. Li Z, Li Q, Qin J. Polym Chem 2011;2:2723–40. Wu W, Huang Q, Qiu G, Ye C, Qin J, Li Z. J Mater Chem 2012;22:18486–95. Wu W, Wang C, Tang R, Fu Y, Ye C, Qin J, et al. J Mater Chem C 2013;1:717–28. Wu W, Qin J, Li Z. Polymer 2013;54:4351–82. Dokládalová L, Bureš F, Kuznik W, et al. Org Biomol Chem 2014;12:5517–27. Janjua M. Inorg Chem 2012;51:11306–14.
Please cite this article as: Liu J, et al. Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2014.12.112i
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores Jialei Liu a,n, Wu Gao b, Xinhou Liu a, Zhen Zhen a a Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China b Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China
art ic l e i nf o
a b s t r a c t
Article history: Received 11 December 2014 Received in revised form 22 December 2014 Accepted 22 December 2014
Organic electro-optic (EO) materials have been widely studied and used in microwave photonic devices, due to their advantages in half-wave voltage, bandwidth, low cost and ease of integration. Nonlinear optical (NLO) chromophores, as the core of organic EO materials, can directly decide the characters of organic EO materials, including large EO activity, long term stability, solubility and optical loss. Auxiliary donors have attracted great attentions in NLO chromophores for their strong electron donating ability and significant isolation effect. This feature article describes the application of auxiliary donor in NLO chromophores, including the EO activities, optical characters, stability, crystal structures and machinability. & 2015 Elsevier B.V. All rights reserved.
Keywords: Functional Electronic materials Organic NLO Chromophore EO coefficient
1. Introduction Organic second-order nonlinear optical materials have been developed greatly in the recent years, due to their potential usage in telecommunications, such as electronic/photonic integrated circuits, phased array radar, terahertz spectroscopy, etc. [1–3]. Electro-optic modulator is an important commercial device for translating ultrafast electrical signals into optical signals for fiber-optic telecommunications. Organic NLO materials have shown us great advantages in the preparation of EO modulators according to its inorganic counterpart of lithium niobate, such as larger EO coefficients, faster intrinsic response times and lower dielectric constants [4–7]. These advantages could greatly improve the devices' characters in half-wave voltage, bandwidth and sensitivity. However, for practical application, some key problems of these materials, such as large first order hyperpolarizability of the chromophores and the adverse strong inter-molecular electrostatic interaction among the chromophores molecules, are also needed to be resolved [8,9]. These problems decide the EO coefficients, machinability, long term stability and optical loss directly. Recently, auxiliary donors which could both improve the first order hyperpolarizability and reduce the inter-molecular electrostatic interaction of the NLO chromophores have been reported. According to the
n
Corresponding author. Tel./fax:861082543529. E-mail address: [email protected] (J. Liu).
strong contribution in improving the EO coefficients and solubility, the design and preparation of NLO chromophores with auxiliary donor would become an important research direction in organic NLO materials. Else, such kind of materials may serve as effective space homogeneity of the chromophores as optical triggers [10,11]. 2. Auxiliary donors and their advantages in improving the first order hyperpolarizability of NLO chromophore In the first days, auxiliary electron donor was introduced to the NLO chromophore just for improving the first order hyperpolarizability. Most of the auxiliary donors had well coplanar with the donor, acceptor and electron bridges, which could effectively improve the density and flow capacity of the conjugate electron cloud. Marks, firstly studied the auxiliary donor effects on molecular hyperpolarizabilities by quantitative calculation in 1997. Their results indicated that NLO response properties of such chromophores were more sensitive to the electron excessive of the bridges than to bridge aromaticity; electron-excessive heterocyclic bridges had less tendency to deplete the electron density from the donor groups and thus increase their donor ability; interposing charged five-membered auxiliary donor fragments between strong donor or acceptor groups resulted in large computed second-order NLO response [12]. Chromophore PTCF (in chart 1) containing pyrrole as an auxiliary electron donor was reported by Ma et al.; large molecular hypolarizabilities (β0 ¼1370 10 30 esu) was achieved after the
http://dx.doi.org/10.1016/j.matlet.2014.12.112 0167-577X/& 2015 Elsevier B.V. All rights reserved.
Please cite this article as: Liu J, et al. Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2014.12.112i
2
J. Liu et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
Chart 1. Structure of the NLO chromophore PTCF and DTCF.
pyrrole being introduced to the chromophore [13]. Dihydrobenzothiazolylide was another kind of electron donors widely used in NLO chromophores. In this donor, two rich electron atoms oxygen and nitrogen make it have stronger electron donating ability; the benzocycle structure confirmed its stability and coplanar. Recently, chromophore DTCF was reported with dihydrobenzothiazolylide electron donor and its NLO activity was studied by Hyper-Raleigh scattering. The result showed that chromophore DTCF with a dynamic first hyperpolarizability of 1900 10 30 esu at 800 nm [14].
3. Multifunctional auxiliary donor and their main role in chromophore isolation Due to its aromatic structure and electron mobility, thiophene is widely used in organic semiconductors [15]. Conjugated structure and sulfur atom makes it also possess electron donating ability. NLO chromophore 1 as shown in chart 2 was synthesized by a facile route [16]. In this chromophore, the thiophene ring was designed as a dualfunction structure playing the role of electron donor and providing steric hindrance. Isolated effect is very important in the design of NLO chromophores with large first order hyperpolarizability. Poor isolated effect can't prevent the formation of reverse dipolar chromophore dimers. If the reverse dipolar chromophore dimers formed, the first order hyperpolarizability of the chromophores couldn't convert into the large electro-optic coefficients of the materials [17,18]. As shown in Fig. 1, the chlorohexyloxy group and thiophene ring were on both sides of the conjugated plane, which effectively protected the π-conjugated bridge from an intermolecular Diels–Alder (DA) cycloaddition reaction [19]. The length of the chlorohexyloxy group was close to the distance from electron to acceptor. This arrangement acted to site-isolate the chromophore within the internal free volume created by the chlorohexyloxy group, which was favorable for dipole orientation in poling process. This molecular conformation (the shadow of Fig. 1) effectively isolated the chromophores and weakened the dipole–dipole interactions. The crystal packing data showed ring centroid to ring-centroid separations of 4.9–5.7 Å, which indicated better site isolation than that of the 4.2 Å reported previously [20,21]. The crystal analysis showed that chromophore 1 displayed excellent site-isolation and effectively reduced the intermolecular electrostatic interactions in the EO response. Chromophore 1 was doped into amorphous polycarbonate (APC) with the loading density of 40% for the preparation of EO films. The poled films showed an exceptionally large EO coefficient (r33 ¼337 pm/V at 1310 nm), which confirmed that the microscopic molecular nonlinearity of chromophores could be effectively translated into macroscopic electro-optic properties. This value is exceptionally large compared to those reported (CLD-1: 70–110 pm/V at 1310 nm) for guest-host EO polymers. N,N-diethylaniline was widely used as electron donors in most of the NLO chromophores, due to its strong electron donating ability and stability. Recently, bis(N,N-diethylaniline)unit was introduced to the NLO chromophores as a new donating moiety [22]. Due to its high electron-density and low cost, Bis(N,N-diethylaniline) unit had
Chart 2. Structure of the chromophores 1, 2, 3 and 4.
Fig. 1. Crystal conformation of chromophore 1.
been widely studied in the dye-sensitized solar cells [23–25], but it was rarely used in NLO chromophore before. According to the reasons below, bis(N,N-diethylaniline)unit was chosen as donors to prepare chromophore 3 and 4 in chart 2: 1) N,Ndiethylaniline could improve the electron-donating ability; 2) One of the N,N-diethylaniline unit acted as both the additional donor and the isolated group. Introduction of some isolated groups to chromophore moieties has been proved to be an effective approach to suppress the dipole interactions among chromophores and improve the poling efficiency, thus achieve much larger macroscopic NLO effects [26–29]. These new chromophores with double benzene rings showed an appropriate angle. Such an appropriate angle made the special Y-type structure which was different from the general NLO chromophores with rod-like structure. Fig.2 showed the r33 values of films containing chromophore 3 (film-A), 4 (film-B) and FTC (film-C) with different chromophore loading densities. Traditional chromophore FTC with the single N, N-diethylaniline donor gained the r33 value from 12 pm/V (10 wt%) to 39 pm/V (25 wt%), while the r33 values of chromophore 3 were
Please cite this article as: Liu J, et al. Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2014.12.112i
J. Liu et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
3
roved for several times. Thiophene auxiliary donor which is introduced in the middle of the electron bridge show us r33 values as large as 337 pm/V at 1310 nm; N,N-diethylaniline auxiliary donor is introduced in the same site as the electron donor show us r33 values as large as 149 pm/V at 1310 nm. These results confirm that auxiliary donor can effectively improve the EO activity of organic EO materials and the position of the auxiliary donor is also an important point to maximize the efficiency of auxiliary donors. Else, other auxiliary donors, such as inorganic clusters, will also be an important direction in the future to dissolve the problems in organic NLO material.
Reference
Fig. 2. EO coefficients of NLO thin films as a function of chromophore loading densities.
gradually improved from 30 pm/V (10 wt%) to 149 pm/V (25 wt%). The similar trend of enhancement was also observed for chromophore 4, whose r33 values increased from 50 pm/V (10 wt%) to 143 pm/V (25 wt%). Through the outcome above, we could obviously see that the chromophores with bis(N,N-diethylaniline)unit as donor had nearly 4 times higher r33 value than the chromophore FTC, illustrating that the double donors of the chromophores significantly increased their macroscopic EO activity. X-shaped push–pull chromophore (in chart 2 chromophore 2) was also reported by Dokladalova et al., this kind of chromophore showed us strong charge transfer efficiency. Large NLO character could be estimated from its strong charge transfer efficiency, though it was not reported directly [30]. Janjua introduced polyoxometalates (POMs) as an auxiliary donor; the strong donor ability showed us great tendency in improving the first order hyperpolarizability and the large rigid structure might have great potential in reducing the intermolecular dipole–dipole interaction and improving the long term stability. Unfortunately, it was just a theoretical calculation, and these compounds were also hard to preparation. But the combination of organic group and inorganic group would be a new orientation in the future [31].
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25]
4. Conclusion By the introduction of auxiliary donor, β values of the NLO chromophore are improved and the dipole interaction among the chromophores is also reduced greatly; the EO coefficients are imp-
[26] [27] [28] [29] [30] [31]
Shi Z, Luo J, Huang S, Polishak B, Zhou X. J Mater Chem 2012;22:951. Yao X, Maleki L. J Opt Soc Am B 1996;13:1725–35. Gheorma I, Gopalakrishnan G. IEEE Photon Technol Lett 2007;19:1011. Tkaczyk S., Kityk I., Ebothe J., Viennois R. J. Phys.: Condens. Matter 16 2231. Jungerman R, Johnsen C, McQuate D, Salomaa K, Zurakowski M, Bray R, et al. J Lightwave Technol 1990;8:1363. Elder D, Benight S, Song J, Robinson B, Dalton L. Chem Mater 2014;26:872. Rao S, Coppola G, Gioffre M, Corte F. Opt Express 2012;20:9351. Huang H, Liu J, Zhen Z, Qiu L, Liu X, Lakshminarayana G, et al. Mater Lett 2012;75:233–5. Liu J, Wang L, Zhen Z, Liu X. Colloid Polym Sci 2012;290:1215–20. Adamiv V, Ebothe J, Piasecki M, Burak Y, Teslyuk I, Plucinski K, et al. Opt Mater 2009;31:685–7. Kityk I, Alzayed N, Reshak A, Plucinski K, Berdowski J, Fuks-Janczarek I, et al. Funct Mater Lett 2011;4:357–9. Albert I, Marks T, Ratner M. J Am Chem Soc 1997;119:6575–82. Ma X, Liang R, Yang F, Zhao Z, Zhang A, Song N, et al. J Mater Chem. 2008;18:1756–64. Ashraf M, Teshome A, Kay A, Gainsford G, Bhuiyan M, Asselberghs I, et al. Dyes Pigments 2013;98:82–92. Roncali J. Macromol Rapid Commun 2007;28:1761–75. Wu J, Bo S, Liu J, Zhou T, Xiao H, Qiu L, et al. Chem Commun 2012;48:9637–9. Liu J, Bo S, Liu X, Zhen Z. J Incl Phenom Macrocycl Chem 2010;68:253–60. Hammond S, Clot O, Firestone K, Bale D, Lao D, Haller M, et al. Chem Mater 2008;20:3425–34. Shi Z, Luo J, Huang S, Zhou X, Kim T, Cheng Y, et al. Chem Mater 2008;20:6372–7. Kwon O, Kwon S, Jazbinsek M, Choubey A, Gramlich V, Gunter P. Adv Funct Mater 2007;17:1750–6. Liao Y, Eichinger B, Firestone K, Haller M, Luo J, Kaminsky W, et al. J Am Chem Soc 2005;127:2758–66. Yang Y, Xu H, Liu F, Wang H, Deng G, Si P, et al. J Mater Chem C 2014;2:5124. Tang K, Liang M, Liu Y, Sun Z, Xue S. Chin J Chem 2011;29:89–96. Dumur F, Mayer CR, Dumas E, Miomandre F, Frigoli M, Secheresse F. Org Lett 2008;10:321–4. Kitamura T, Ikeda M, Shigaki K, Inoue T, Anderson N, Ai X, et al. Chem Mater 2004;16:1806–12. Li Z, Li Q, Qin J. Polym Chem 2011;2:2723–40. Wu W, Huang Q, Qiu G, Ye C, Qin J, Li Z. J Mater Chem 2012;22:18486–95. Wu W, Wang C, Tang R, Fu Y, Ye C, Qin J, et al. J Mater Chem C 2013;1:717–28. Wu W, Qin J, Li Z. Polymer 2013;54:4351–82. Dokládalová L, Bureš F, Kuznik W, et al. Org Biomol Chem 2014;12:5517–27. Janjua M. Inorg Chem 2012;51:11306–14.
Please cite this article as: Liu J, et al. Benefits of the use of auxiliary donors in the design and preparation of NLO chromophores. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2014.12.112i