氯鋁酞青素-乙醇溶液中溶質傳輸之研究

Study of Solute Migration of Chloroaluminum Phthalocyanine Dissolved in Ethanol

廖建洲(Liao, Jainzhou)

指導教授 ： 魏台輝

國立中正大學/理學院/物理學系/碩士(2011年)

摘要

本論文旨在調查氯鋁酞青素-乙醇溶液(chloroaluminum phthalocyanine-ethanol，簡稱為ClAlPc-ethanol)在秒(s)時域的熱擴散(thermal diffusion，溫度梯度引起的溶質分子質量傳輸現象)、質量擴散(mass diffusion，不均勻的溶質分子濃度所引起的溶質分子質量傳輸效應)以及對流等效應。我們將不同功率的CW He-Ne雷射(632.8nm)以及DPSS雷射(532nm)光截成2 s或5 s的脈衝，以之垂直入射至1 mm 7  104 M的ClAlPc-ethanol溶液，然後量測穿透率(穿透光功率除以入射光功率)隨時間變化的情形。在632.8 nm的實驗中，我們將入射光傳播方向分成垂直與水平於桌面等兩種方向，而在532 nm的實驗中，則只採用入射光垂直於光學桌面的裝置。逐一考量穿透光功率隨入射光傳播方向、光波長、光功率以及時間變化的情形，我們確認以上所提各種效應。
結合實驗觀察與理論分析，我們推論溶質分子藉吸收TEM00模態的雷射光能而提升溶液溫度，並沿雷射光側向(lateral direction)產生溫度梯度，驅動溶質分子由光斑中心往光斑邊緣傳輸，造成熱擴散效應，使光穿透率隨時間上升；當熱擴散效應將溶質分子由光斑中心推往往光斑邊緣之後，質量擴散將溶質分子由高溶質濃度(光斑邊緣)區推回低溶質濃度(光斑中心)區，減緩光穿透率上升速率。當入射光傳播方向水平於桌面的時候，我們在熱擴散與質量擴散之外進一步發現對流效應的產生，造成光斑中心的偏移以及光穿透率隨時間的變化由上升轉為下降。

關鍵字

質量擴散 ； 熱擴散 ； 五能級 ； 氯鋁酞青素 ； 對流

並列摘要

In this thesis, we investigate thermal and mass diffusions (mass transport induced by temperature and concentration gradients respectively) and convection in an 1 mm thick 7  104 M ethanolic solution of chloroaluminum phthalocyanine, dubbed as ClAlPc-ethanol, with a CW HeNe laser (632.8 nm) and a CW DPSS laser (532 nm), both operated at the TEM00 mode. In the study with HeNe laser, we measure, in both the vertical and horizontal irradiation geometries, the transmittance (transmitted power divided by incident power) of the 632.8 nm laser light disrupted into 2 and 5 s pulses by a shutter. However, in the study with DPSS laser, we measure in the horizontal irradiation geometry alone, the transmittance of the 532 nm laser light disrupted into 2 and 5 s pulses. Here, by vertical or horizontal irradiation geometry, we mean the sample is placed with its incident surface parallel or vertical to the optical table surface and the laser beams propagate vertically downward or parallel to the optical table surface. As a result, we observe the influence of transmittance by the light propagation directions, wavelengths, power and time. Accordingly, we verify the abovementioned thermal and mass diffusions as well as convection.
Based on the experimental results and theoretical analysis, we infer that photo absorption of the TEM00 mode laser light by ClAlPc molecules results in a temperature gradient along the lateral direction which drives the outward solute migration from the laser beam center. This weakens the absorption and hence increases the transmittance of the sample. Afterwards, mass migration is ignited and pushes the solute molecules from the high concentration region (beam periphery) toward the low concentration region (beam center). This slows down the transmittance increase with time. In particular, when the light propagation direction is parallel to the optical table surface, convection occurs and causes the downward beam deflection and a turn over of the transmittance from increase to decrease with time.

並列關鍵字

Thermal diffusion ； ClAlPc ； Chloroaluminum Phthalocyanine ； Mass diffusion ； convection

參考文獻

[6] Tai-Huei Wei; Tzer-Hsiang Huang; Mu-Shih Lin, “Signs of nonlinear refraction in chloroaluminum phthalocyanine solution”, Appl. phys. lett. 72, pp.2505-2507, 1998.

[7] Tai-Huei Wei; Tzer-Hsiang Huang; Jung-Kuang Hu, “Electronic energy dissipation in chloro-aluminum phthalocyanine/methanol system following nonlinear interaction with a train of picosecond pulses”, J. Chem. Phys., 116, pp.2536-2541, 2002.

[11] J.H. Brannon, and D. Madge, J. Am. Chem. Soc. 102:1, 62(1980).

[12] T.H. Wei, T.H. Huang, H.D. Lin, and S.H. Lin, Appl. Phys. Lett. 67(16), 2266-8 (1995); Opt. and Quan. Elec. 28, 1495-1508(1996).

[13] Tai-Huei Wei; T.-H Huang; S. Yang, D. Liu; J.-K. Hu; C.-W. Chen “Z-scan study of optical nonlinearity in C60-toluene solution”, Mol. Phys. 103 (14), 1847-1857 (2005).