本論文主要研究高分子聚乙烯咔唑(簡稱PVK)薄膜用於液晶元件製作所具備的光電與光熱效應。主要將分成兩大部分，第一部分研究顯示出PVK薄膜在UV光照射後，PVK分子側鏈受熱所產生的微布朗運動程度不同，影響液晶排列方向，結果顯示出液晶轉動起始溫度的不同是受到UV光照射PVK薄膜的時間長短所影響，因此，我們利用UV光照射與熱控的條件控制，來製作相位光柵，再針對此相位光柵量測其光電特性，可知其相位光柵由Twisted nematics (TN)與Homogeneous兩種液晶排列態所構成，並由實驗得知，TN grating其優點在於入射光偏振狀態與繞射光強度無關，此結果於光通訊上之應用甚為重要。第二部分為利用PVK之光導體特性，在固定外加直流電場下改變照射UV光的光強度來進行動態灰階控制，因此它有潛力作為智慧玻璃(smart window)之應用。

This thesis studies liquid crystal (LC) devices with the cell coated with poly(N-vinylcarbazole) (PVK) film under the exposure of ultraviolet (UV) light irradiation and temperature effect. The studies are divided into two parts. The first part demonstrates that the alignment effect of PVK film on LC after the cell being irradiated with ultraviolet (UV) light and heated is changed. Before UV irradiation, LCs align perpendicularly to the rubbing direction due to the side strong dipole force. Yet, after UV irradiation and heating, LCs align toward the rubbing direction. The reason is that the micro-Brownian motion of the PVK side chains eliminated the dipole aligning force on LCs. The results show UV exposure time on the PVK film is the key to determine the temperature required starting the switch of LCs alignment. Moreover, we demonstrates the optical properties of the PVK film-coated LC cells under the optically and thermally treatments to fabricate a TN grating. The detailed electro-optical characteristics of the TN grating are measured. The second experiment investigates the photoconductivity of a PVK film. Due to the photoconductivity, the TN LC cell coated with a PVK film could be switched between multiple gray scales optically and electrically. Thus, it possesses potential for being applied for use as a smart window.

[1] P. J. Bos and K. R. Koehler/ Beran, Mol. Crystal. 113, 329 (1984).
[2] M. Schadt, H. Seiberle, A. Schuster, Nature. 381, 212 (1996).
[3] Y. Iwamoto, Y. Toko, H. Hiramoto and Y. Iimura. Dig. Tech. Papers SID’00 31, 902 (2000).
[4] Pierre-Olivier Bussiere, Agnes Rivaton, Sandrine Therias, and Jean-Luc Gardette, “Multiscale Investigation of the Poly(N-vinylcarbazole) Photoageing Mechanism” J. Phys. Chem. B, 116, 802-812 (2012).
[5] A. Rivaton, B. Mailhot, G. Derderian, P. O. Bussiere, and J.-L. Gardette* “Investigation of the Photophysical Processes and Photochemical Reactions Involved in PVK Films Irradiated at λ > 300 nm” Macromolecules 36, 5815–5824 (2003).
[6] Y.-D. Chen, K.-T. Cheng, C.-K. Liu and Andy Y.-G. Fuh* “ Polarization rotators fabricated by thermally-switched liquid crystal alignments based on rubbed poly(N-vinylcarbazole) films ” , Optics Express 19, 7553-7558 (2011)
[7] P. Yeh and C. Gu, “ Optics of Liquid Crystal Display ” , John Wiley & Sons, New York (1999).
[8] E. B. Priestley, P. J. Wojtowicz and P. Sheng, “Introduction to Liquid Crystals” , Princeton, New Jersey (1975).
[9] 松本正一‧角田市良 (劉瑞祥 譯)，「液晶之基礎與應用」，國立編譯館出版，中華民國九十二年。
[10] D. Statman, E. Page, V. Werner and J. C. Lombardi, Phys. Rev. E 75, 021703 (2007).
[11] C.-R. Lee, T.-S. Mo, K.-T. Cheng, T.-L. Fu and Andy Y.-G. Fuh, Appl. Phys. Lett. 83, 4285 (2003).
[12] O. Francescangeli, S. Slussarenko and F. Simoni, Phys. Rev. Lett. 82, 1885 (1999).
[13] F. Reintzer, Monatsh. Chem. 9, 421 (1888).
[14] Letter from F. Reintzer to O. Lehmann, reported by H. Keller, Mol. Cryst. Liq. Cryst. 21,1 (1973).
[15] I. C. Khoo, “ Liquid Crystals Physical Properties and Nonlinear Optical Phenomena ” , John Wiley & Sons, New York (1995).
[16] M. Marinelli and F. Mercuri, Phys. Rev. E 61, 1616 (2000).
[17] A. Yariv, “ Optical Electronics in Modern Communications ”, Oxford University Press, New York, (1997) .
[18] H.-S. Kitzerrow, C. Bahr, “ Chirality in Liquid Crystals ’’, Springer, New York (2001).
[19] S. Chandrasekhar, Contemp. Phys. 29, 527 (1988).
[20] X. J. Wang, Q. F. Zhou. “ Liquid Crystalline Polymers ’’, World Scientific (2004).
[21] H. Finkelmann, G. Rehage. Adv. Polym. Sci., 60, 99 (1984).
[22] V. P. Shibaev, N. A. Plate. Adv. Polym. Sci., 60, 173 (1984).
[23] A. Yariv, “ Quantum Electronics ’’, Wiley, New York, (1988).
[24] 朱自強, 王仕璠, 蘇顯渝 編著, 現代光學教程, 四川大學出版社, 成都, (1990).
[25] Peter J. Collings and Michael Hird, “ Introduction to Liquid Crystals Chemistry and Physics ’’, Taylor & Francis Ltd, Hampshire, (1997).
[26] 黃子強 編著, 液晶顯示原理, 國防工業出版社出版, 北京, (2006)。
[27] P. G, De. Gennes and J. Prost, “ The Physics of Liquid Crystal ’’, 2nd ed., Oxford University Press, New York (1933).
[28] 陳園迪,博士論文,「聚乙烯基咔唑薄膜式液晶元件之特性：配向效應、熱反應、相位分離及其新穎應用」,國立成功大學光電科學與工程研究所 (2012)
[29] K. Nakajima, H. Wakemmoto, S. Sato, F. Yokotani, S. Ishihara and Y. Matsuo, Mol. Cryst. Liq. Cryst. 180, 223 (1990).
[30] 胡赓祥, 蔡珣 編著, 材料科學基礎, 上海交通大學出版社 (2001).
[31] Bittner, Reinhard “ Basic Investigations on PVK-based Photorefractive Polymers Focussing on their Applicability as Mass Data Storage Media ”, PhD thesis, Universität zu Köln (2003).
[32] M. Kaczmarek and A. Dyadyusha, “Structured, photosensitive PVK and PVCN polymer layers for control of liquid crystal alignment”, J. Nonlinear Opt. Phys. Mater. 12, 547–555 (2003).
[33] Henk Bolink, “Photorefractive Polymers”, University of Groningen, Netherlands. (1997)
[34] P. D’Angelo, M. Barra, A. Cassinese, M. G. Maglione, P.Vacca, C. Minarini, A. Rubino “Electrical transport properties characterization of PVK poly(N-vinylcarbazole) for electroluminescent devices applications”, Solid-State Electronics. 51, 123-129 (2007)
[35] Hui Jin, Yan-bing Hou, Xian-guo Meng, Ai-wei Tang and Feng Teng, “Photoconductive properties of PVK: Alq3 blend films studied by steady-state and time-resolved transient photocurrent spectra”, Chinese Journal of Polymer Science. Vol. 26, No. 3, 249-254 (2008)
[36] H. Mada and K. Osajima, J. Appl. Phys. 60, 3111-3113 (1986)
[37] A. Sugimura, N. Matsui, Y. Takahashi, H. Sonomura, H. Naito, and M. Okuda, Phys. Rev. B. 43, 8272-8276 (1990)
[38] A. Mochizuki, T. Yoshihara, K. Motoyoshi, and S. Kobayashi, J. Jpn. Appl. Phys. 29, 322-325 (1990)
[39] Berreman D W, Phys. Rev. Lett. 28, 1683 (1972).
[40] Pochi Yeh et al. “Optical of Liquid Crystal Display”, John Wiley & Sons Inc. (2006)
[41] The ALCOM Educational Outreach Newsletter. Issues 1-6. A Publication of the National Science Foundation and Technology Center for Advanced Liquid Crystalline Optical Materials (ALCOM) (2011)
[42] 吳威諺,碩士論文,「光配向摻雜染料之液晶薄膜產生扭轉光柵之繞射偏振研究」,國立成功大學物理研究所 (2004)