نانومقیاس

نانومقیاس

بهبود خواص دی‌الکتریکی و کلیدزنی الکترواپتیکی بلورهای مایع نماتیک با استفاده از نقاط کوانتومی ZnCdTeS با خاصیت نورتابی در طول موج‌های مختلف

نوع مقاله : مقاله پژوهشی

نویسندگان
زهرا صیدالی لیر 1، 2
سپیده شیشه بر 3
احسان سهیلی 4
محمد صباییان 5، 2
1 گروه فیزیک، دانشکده علوم، دانشگاه شهید چمران اهواز، اهواز، ایران.
2 مرکز تحقیقات لیزر و پلاسما، دانشگاه شهید چمران اهواز، اهواز، ایران
3 گروه فیزیک، دانشکده علوم، دانشگاه شهید چمران اهواز، اهواز، ایران
4 گروه فیزیک، دانشکده علوم، دانشگاه ایلام، ایلام، ایران
5 گروه فیزیک، دانشکده علوم، دانشگاه شهید چمران اهواز، اهواز،ایران
چکیده
در این پژوهش، از نقاط کوانتومی ZnCdTeS با گسیل نور در طول موج‌های مختلف جهت بهبود خواص دی‌الکتریکی و الکترو‌اپتیکی سلول‌های بلور مایع نماتیک E7 استفاده شده است. مؤلفه‌های گذردهی دی‌الکتریکی (ɛ‖ وɛꓕ) و ناهمسانگردی دی‌الکتریکی (Δɛ) نمونه‌های بلور مایع نماتیک حاوی نقاط کوانتومی ZnCdTeS به‌صورت تابعی از دما اندازه‌گیری شد. در فاز نماتیک، با افزودن نقاط کوانتومی، ɛ‖ در مقایسه با ɛꓕ افزایش بیشتری می‌یابد. در حضور نقاط کوانتومی با نشر نور قرمز، افزایش قابل توجه ɛ‖ منجر‌به افزایش حدود 19 درصدی ناهمسانگردی دی‌الکتریکی سامانه شده است. نتایج دی‌الکتریکی نشان می‌دهد که محیط بلور مایع موجب القاء آرایه‌هایی یک‌بعدی از نقاط کوانتومی درون سامانه می‌شود و این امر موجب بهبود خواص دی‌الکتریکی سلول می‌شود. مطابق نتایج الکترواپتیکی، حضور نقاط کوانتومی موجب کاهش قابل توجهی در ولتاژ آستانۀ سلول‌های بلور مایع نماتیک می‌شود. مقدار ولتاژ آستانه از V 57/2 برای بلورمایع خالص به V 21/2 برای بلور مایع حاوی نقاط کوانتومی کاهش یافته است. نقاط کوانتومی با جذب ناخالصی‌های یونی درون سامانه، موجب کاهش اثرات پوششی و افزایش میدان مؤثر سامانه می‌شوند. افزایش میدان موثر درون سلول، افزایش ناهمسانگردی و بهبود برهم‌کنش میان بلور مایع و نقاط کوانتومی موجب بهبود خواص کلیدزنی سلول شده است.
کلیدواژه‌ها
بلور مایع نماتیک
خواص دی‌الکتریکی
خواص الکترواپتیکی
ولتاژ آستانه

موضوعات

عنوان مقاله English

Enhanced dielectric and electro-optical switching properties of nematic liquid crystals using ZnCdTeS quantum dots with luminescent property at different emission wavelengths

نویسندگان English

zahra seidalilir 1 2
Sepideh Shishehbor 3
Ehsan Soheyli 4
Mohammad Sabaeian 5 2
1 Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
3 Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
4 Department of Physics, Faculty of Science, Ilam University, 65315-516, Ilam, Iran.
5 Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
چکیده English

Abstract: In this study, ZnCdTeS quantum dots (QDs) with luminescent properties at different emission wavelengths were utilized to enhance the dielectric and electro-optical characteristics of nematic liquid crystal (NLC) cells. At various temperatures, the dielectric permittivity components (ɛ‖ and ɛꓕ) and dielectric anisotropy (Δɛ) of NLC samples containing ZnCdTeS QDs were measured. ɛ‖ increases considerably more than ɛꓕ in the nematic phase when QDs are introduced. The dielectric anisotropy of the system has increased by approximately 19% in the presence of QDs with red emission, which is a result of a significant enhancement of ɛ‖. The NLC environment induces one-dimensional arrays of QDs in the system, which enhances the dielectric properties of the system, as demonstrated by the dielectric results. The electro-optical findings indicate that including QDs substantially reduces the threshold voltage of NLC cells. Incorporating quantum dots into liquid crystal led to a reduction in the threshold voltage from 2.57 V for pure NLC to 2.21 V. QDs improve the effective field of a system by reducing the screening effects caused by ionic impurities in the system. Anisotropy enhancement, effective field increase within the cell, and QD-NLC interaction improvement all contribute to the enhancement of the cell's switching characteristics.

کلیدواژه‌ها English

Nematic liquid crystals
dielectric properties
electro-optical properties
threshold voltage
[1] Andrienko D. Introduction to liquid crystals. Journal of Molecular Liquids. 2018;267:520–541. https://doi.org/10.1016/j.molliq.2018.01.175.
[2] Tschierske C. Development of Structural Complexity by Liquid‐Crystal Self‐assembly. Angewandte Chemie International Edition. 2013; 52: 8828–8878. https://doi.org/10.1002/anie.201300872.
[3] Jessy P, Radha S, Patel N. Highly improved dielectric behaviour of ferronematic nanocomposite for display application. liquid crystal. 2019;46:772–786. https://doi.org/10.1080/02678292.2018.1528642.
[4] Kocakülah G, Önsal G, Goksen K, Ercan İ, Köysal O. Concentration effect of Cadmium Selenide Sulphide/Zinc Sulphide quantum dots on electro-optic and dielectric properties in nematic liquid crystals composite. Physica B: Condensed Matter. 2018;550:47–59. https://doi.org/10.1016/j.physb.2018.09.012.
[5] Durbin SD, Arakelian SM, Shen YR. Optical-Field-Induced Birefringence and Freedericksz Transition in a Nematic Liquid Crystal. Physical Review Letters. 1981;47:1411–1414. https://doi.org/10.1103/PhysRevLett.47.1411.
[6] Esteves C, Ramou E, Porteira ARP, Moura Barbosa AJ, Roque ACA. Seeing the Unseen: The Role of Liquid Crystals in Gas‐Sensing Technologies. Advanced Optical Materials. 2020;8. https://doi.org/10.1002/adom.201902117.
[7] Mather J, Jones LP, Gass P, Imai A, Takatani T, Yabuta K. Potential improvements for dual directional view displays. Applied Optics. 2014;53:769. https://doi.org/10.1364/AO.53.000769.
[8] Woltman SJ, Jay GD, Crawford GP. Liquid-crystal materials find a new order in biomedical applications. Nature Materials. 2007;6:929–38. https://doi.org/10.1038/nmat2010.
[9] Seidalilir Z, Shishehbor S, Soheyli E, Sabaeian M. Impact of red emissive ZnCdTeS quantum dots on the electro-optic switching, dielectric and electrochemical features of nematic liquid crystal: Towards tunable optoelectronic systems. Optical Materials. 2023;140:113868. https://doi.org/10.1016/j.optmat.2023.113868.
[10] Sebastián N,  Osterman N,  Lisjak D,  Čopič M,  Mertelj A, Director reorientation dynamics of ferromagnetic nematic liquid crystals. Soft Matter. 2018; 14: 7180-7189.  
https://doi.org/10.1039/C8SM01377B.
[11] Jang S-W, Choi W, Kim S, Lee J, Na S, Ham S, et al. Complex spatial light modulation capability of a dual layer in-plane switching liquid crystal panel. Scientific Reports. 2022;12:8277. https://doi.org/10.1038/s41598-022-12292-4.
[12] Choi J-C, Lee J-W, Lee D-J, Park Y, Kim H-R. Flicker‐Free Fringe‐Field Switching Liquid Crystal Display Operable at Extremely Low Frequencies for Power Saving. Advanced Engineering Materials. 2021;23. https://doi.org/10.1002/adem.202100174.
[13] Shivaraja SJ, Gupta RK, Kumar S, Manjuladevi V. Enhanced electro-optical response of nematic liquid crystal doped with functionalised silver nanoparticles in twisted nematic configuration. liquid crystal. 2020; 47: 1678–1690. https://doi.org/10.1080/02678292.2020.1755901.
[14] Chen W-T, Chen P-S, Chao C-Y. Effect of Doped Insulating Nanoparticles on the Electro-Optical Characteristics of Nematic Liquid Crystals. Japanese Journal of Applied Physics. 2009;48:015006. https://doi.org/10.1143/JJAP.48.015006.
[15] Huang Y, Bos PJ, Bhowmik A. The ion capturing effect of 5° SiOx alignment films in liquid crystal devices. Journal of Applied Physics. 2010;108. https://doi.org/10.1063/1.3481088.
[16] Chou T-R, Hsieh J, Chen W-T, Chao C-Y. Influence of particle size on the ion effect of TiO2 nanoparticle doped nematic liquid crystal cell. Japanese Journal of Applied Physics. 2014;53:071701. https://doi.org/10.7567/JJAP.53.071701.
[17] Hicks SE, Hurley SP, Yang YC, Yang D-K. Electric polarization frozen by a polymer network in nematic liquid crystals. Soft Matter. 2013;9:3834. https://doi.org/10.1039/c3sm27594a.
[18] Maleki A, Seidali Z, Zakerhamidi MS, Ara MHM. Dichroic ratio and order parameters of some sudan dyes doped in nematic liquid crystalline matrix. Optik. 2015;126:5473–5477. https://doi.org/10.1016/j.ijleo.2015.09.100.
[19] Huang CY, Selvaraj P, Senguttuvan G, Hsu CJ. Electro-optical and dielectric properties of TiO2 nanoparticles in nematic liquid crystals with high dielectric anisotropy. Journal of Molecular Liquids. 2019;286:110902. https://doi.org/10.1016/j.molliq.2019.110902.
[20] Singh BP, Sikarwar S, Tripathi S, Agarwal S, Sah M, Manohar R, et al. Thermodynamic and spectroscopic characterization of a weakly polar liquid crystalline compound dispersed with polyvinyl pyrrolidone capped gold nanoparticles. Journal of Molecular Liquids. 2022;354:118889. https://doi.org/10.1016/j.molliq.2022.118889.
[21] Chung H-K, Park H-G, Ha Y-S, Han J-M, Lee J-W, Seo D-S. Superior electro-optic properties of liquid crystal system using cobalt oxide nanoparticle dispersion. liquid crystal. 2013;40:632–8. https://doi.org/10.1080/02678292.2013.773092.
[22] Oh C-W, Park E-G, Park H-G. Enhanced electro-optical properties in titanium silicon oxide nanoparticle doped nematic liquid crystal system. Surface and Coatings Technology. 2019;360:50–5. https://doi.org/10.1016/j.surfcoat.2019.01.014.
[23] Basu R. Enhancement of polar anchoring strength in a graphene-nematic suspension and its effect on nematic electro-optic switching. Physical Review E. 2017;96:012707. https://doi.org/10.1103/PhysRevE.96.012707.
[24] Singh G, Fisch M, Kumar S. Emissivity and electrooptical properties of semiconducting quantum dots/rods and liquid crystal composites: a review. Reports on Progress in Physics 2016;79:056502. https://doi.org/10.1088/0034-4885/79/5/056502.
[25] Basu R, Iannacchione GS. Evidence for directed self-assembly of quantum dots in a nematic liquid crystal. Physical Review E. 2009;80:010701. https://doi.org/10.1103/PhysRevE.80.010701.
[26] Atzin N, Guzmán O, Gutiérrez O, Hirst LS, Ghosh S. Free-energy model for nanoparticle self-assembly by liquid crystal sorting. Physical Review E. 2018;97:062704. https://doi.org/10.1103/PhysRevE.97.062704.
[27] Verma YK, Inman RH, Ferri CGL, Mirafzal H, Ghosh SN, Kelley DF, et al. Electrical modulation of static and dynamic spectroscopic properties of coupled nanoscale GaSe quantum dot assemblies. Physical Review B. 2010;82:165428. https://doi.org/10.1103/PhysRevB.82.165428.
[28] Seidalilir Z, Soheyli E, Sabaeian M, Sahraei R. Enhanced electrochemical and electro-optical properties of nematic liquid crystal doped with Ni:ZnCdS/ZnS core/shell quantum dots. Journal of Molecular Liquids.  2020;320:114373. https://doi.org/10.1016/j.molliq.2020.114373.
[29] Zakerhamidi MS, Shoarinejad S, Mohammadpour S. Fe3O4 nanoparticle effect on dielectric and ordering behavior of nematic liquid crystal host. Journal of Molecular Liquids. 2014;191:16–19. https://doi.org/10.1016/j.molliq.2013.11.020.
[30] Khoo I-C, Wu S-T. Optics and Nonlinear Optics of Liquid Crystals. WORLD SCIENTIFIC; 1993. https://doi.org/10.1142/1630.
[31] Soheyli E, Zargoush S, Yazici AF, Sahraei R, Mutlugun E. Highly luminescent ZnCdTeS nanocrystals with wide spectral tunability for efficient color-conversion white-light-emitting-diodes. Journal of Physics D: Applied Physics. 2021;54:505110. https://doi.org/10.1088/1361-6463/ac26f5.
[32] Dalir N, Javadian S, Kakemam J, Yousefi A. Evolution of electro-chemical and electro-optical properties of nematic liquid crystal doped with graphene oxide. Journal of Molecular Liquids. 2018;265:398–407. https://doi.org/10.1016/j.molliq.2018.05.138.
[33] Ranjkesh A, Ebrahimpour N, Zakerhamidi MS, Seyedahmadian SM. Temperature-dependent dielectric property of a nematic liquid crystal doped with two differently–shaped tungsten oxide (W18O49) nanostructures. Journal of Molecular Liquids. 2022;348:118024. https://doi.org/10.1016/j.molliq.2021.118024.
[34] Kaszynski P, Januszko A, Glab KL. Comparative Analysis of Fluorine-Containing Mesogenic Derivatives of Carborane, Bicyclo[2.2.2]octane, Cyclohexane, and Benzene using the Maier–Meier Theory. The Journal of Physical Chemistry B. 2014;118:2238–2248. https://doi.org/10.1021/jp411343a.
[35] Basu R, Kinnamon D, Garvey A. Nano-electromechanical rotation of graphene and giant enhancement in dielectric anisotropy in a liquid crystal. Applied Physics Letters. 2015;106. https://doi.org/10.1063/1.4921752.
[36] Mishra S, Manjuladevi V, Gupta RK. Effect of shape of ZnO nanoparticle on electro-optic and dielectric properties of nematic liquid crystal. Journal of Molecular Liquids. 2023;386:122482. https://doi.org/10.1016/j.molliq.2023.122482.
[37] Ayeb H, Derbali M, Mouhli A, Soltani T, Jomni F, Fresnais J, et al. Viscoelastic and dielectric properties of 5CB nematic liquid crystal doped by magnetic and nonmagnetic nanoparticles. Physical Review E. 2020;102:052703. https://doi.org/10.1103/PhysRevE.102.052703.
[38] Dark ML, Moore MH, Shenoy DK, Shashidhar R. Rotational viscosity and molecular structure of nematic liquid crystals. Liquid crystal. 2006;33:67–73. https://doi.org/10.1080/02678290500450634.
 
نانومقیاس
دوره 11، شماره 1
بهار 1403
صفحه 41-29

  • تاریخ دریافت 29 آبان 1402
  • تاریخ بازنگری 10 بهمن 1402
  • تاریخ پذیرش 17 بهمن 1402