一般的太陽能選擇性吸收膜(Solar Selective Absorber, SSA)是在基板表面直接塗上吸熱塗料或氣相沉積的方式製作，因此多為平面的構造，大部分的設計會隨著入射光角度增加轉換效率下降幅度甚多，而許多研究指出微奈米的表面結構對於大角度入射光有很好的抗反射效果，因此本研究嘗試製作次微米結構的太陽能選擇性吸收膜，增加大角度入射光的轉換效率。
實驗先以旋轉塗佈的方式再玻璃基板上製作出聚苯乙烯微奈米球自組裝單層鋪排，再搭配二氧化鈦溶膠凝膠的塗佈，製作出平均直徑387 nm、高度117.8 nm的二氧化鈦碗形孔洞陣列微結構。
太陽能選擇性吸收膜的部分則利用銀作為熱輻射高反射層降低紅外光熱輻射放射率，鈦和二氧化鈦作為拓寬吸收波段的金屬-介電質互層堆疊(D-M-D)，而最表面鍍上一層二氧化矽利用其相對的低折射率、高表面硬度達到抗反射及抗刮蝕的效果，以真空蒸鍍的方式將此Ag/ TiO2/ Ti/ TiO2/ SiO2多層型選擇性吸收膜覆蓋在二氧化鈦碗形孔洞陣列微結構上。
相較於相同堆疊的平面太陽能選擇性吸收膜，增加了此微結構的太陽能選擇性吸收膜在8~75度角、波長400~1000奈米的入射光照射下，吸收率皆有程度不等的提升，提升幅度呈現隨角度加大的趨勢，在75度入射光下吸收率提升了6.5%，而在8~75度入射角下整體平均效能(α/ε)微幅提升了0.37%。

Solar selective absorber (SSA) is a solar energy conversion device normally fabricated using painting or vapor-deposition methods on a flat substrate. The energy conversion efficiency of the flat surface can be reduced as the incident angle increased. To solve this problem, microstructures are claimed including wide-angle antireflection. Thus, the energy conversion efficiency of the SSA with micro-structures was studied for wide-angle incident lights.
Based on the self-assembly of Polystyrene(PS) spheres and the sol-gel coating of TiO2, the TiO2 microstructure array of hexagonal close packing(HCP) and bowl-like holes were achieved. The hole size was 387 nm in diameter and 117.8 nm in height on the surface of BK-7 substrate.
Then a multi-layered SSA was deposited on the microstructure by E-gun evaporator. The SSA consist of metals and dielectrics as follows: a thin Ag layer was applied as IR reflector to reduce the thermal emission of substrate; Ti and TiO2 composed a Dielectric-Metal-Dielectric (D-M-D) stack to broaden the anti-reflection band of visible spectrum; and SiO2 was coated at last as an anti-reflection and anti-scratch layer. The SSA came to be a stack of Ag/ TiO2/ Ti/ TiO2/ SiO2 on the surface of microstructure.
The average absorptance(α) between 400nm ~ 1000nm of the micro-structured SSA is successfully improved for the incident angle between 8°~75° comparing to that of flat ones. The average absorptance increases 6.5% for the 75° incident angle and the average conversion efficiency (α/ε) increases 0.37% for the incident angle between 8°~75°.

[1] http://www.fondriest.com/environmental-measurements/
parameters/ weather/photosynthetically-active-radiation/
[2] Q.-C. Zhang, "Recent progress in high-temperature solar selective coatings," Solar Energy Materials and Solar Cells, vol. 62, pp. 63-74, 2000.
[3] N. P. Sergeant, O. Pincon, M. Agrawal, and P. Peumans, "Design of wide-angle solar-selective absorbers using aperiodic metal-dielectric stacks," Optics express, vol. 17, pp. 22800-22812, 2009.
[4] X. Xiao, G. Xu, B. Xiong, D. Chen, and L. Miao, "The film thickness dependent thermal stability of Al2O3: Ag thin films as high-temperature solar selective absorbers," Journal of Nanoparticle Research, vol. 14, pp. 1-11, 2012.
[5] W.-X. Zhou, Y. Shen, E.-T. Hu, Y. Zhao, M.-Y. Sheng, Y.-X. Zheng, et al., "Nano-Cr-film-based solar selective absorber with high photo-thermal conversion efficiency and good thermal stability,” Optics express, vol. 20, pp. 28953-28962, 2012.
[6] N. P. Sergeant, M. Agrawal, and P. Peumans, "High performance solar-selective absorbers using coated sub-wavelength gratings," Optics express, vol. 18, pp. 5525-5540, 2010.
[7] S. K. Kumar, S. Suresh, S. Murugesan, and S. P. Raj, "CuO thin films made of nanofibers for solar selective absorber applications," Solar Energy, vol. 94, pp. 299-304, 2013.
[8] G. A. Nyberg, H. Craighead, and R. Buhrman, "Surface roughness and thermal stability of graded cermet photothermal absorber coatings with very high absorptivities," Thin Solid Films, vol. 96, pp. 185-190, 1982.
[9] H. C. Barshilia, S. John, V. Mahajan, “Nanometric multi-scale rough, transparent and anti-reflective ZnO superhydrophobic coatings on high temperature solar absorber surfaces," Solar Energy Materials and Solar Cells, vol. 107 pp. 219-224, 2012.
[10] S. Khamlich, M. Maaza, “Cr/α-Cr2O3 monodispersed meso-spherical particles for mid-temperature solar absorber application," Energy Procedia, vol. 68 pp. 31-36, 2015.
[11] D. Ding, W. Cai, “Self-assembled nanostructured composites for solar absorber," Materials Letters, vol. 93 pp. 269-271, 2013.
[12] A. Karoro, Z.Y. Nuru, L. Kotsedi, Kh. Bouziane, B.M. Mothudi, M. Maaza, “Laser nanostructured Co nanocylinders-Al2O3 cermets for enhanced & flexible solar selective absorbers applications," Applied Surface Science, vol. 347 pp. 679-684, 2015.
[13] 李正中, ''薄膜光學與鍍膜技術 第七版'' 藝軒圖書出版社, 38~42頁, 95~98頁, 2012。
[14] 陳煜升, ''應用光學導納軌跡法提升太陽能選擇性吸收膜之光熱轉換效率研究'' 國立中央大學, 碩士論文, 民國103年。
[15] 李正中, ''薄膜光學與鍍膜技術 第七版'' 藝軒圖書出版社, 56~57頁, 104~115頁, 2012。
[16] https://allhomosapienswelcome.wordpress.com/2012/07/26/
peering-into-a-micro-world/
[17] 李正中, ''薄膜光學與鍍膜技術 第七版'' 藝軒圖書出版社, 278~327頁, 2012。
[18] P. A. Kralchechsy, N. D. Denkovd, "Capillary Forces and Structuring in Layers of Colloid Particles," Curr. Interf.Sci., vol. 6, pp. 383-401, 2001.
[19] P. A. Kralchechsy, K. Nagayama, "Capillary Forces between Colloid Particles," Langmuir., vol. 10, pp. 23-26, 1994.
[20] E. Adachi, A. S. Dimitrov, K. Nagayama, "Strip Patterns Formed on a Glass Surface During Droplet Evaporation," Langmuir., vol. 11, pp. 1057-1060, 1995.
[21] 王升平, ''四氯化碳製作納米二氧化鈦透明結晶膜及其應用'' 國立中央大學, 碩士論文, 民國89年。
[22] 楊淑梅, ''以溶膠-凝膠程序製備無機複合膜之抗高溫氧化及防蝕性質研究'' 私立中原大學, 碩士論文, 民國90年。
[23] YONGFA ZHU, LI ZHANG, CHONG GAO, LILI CAO, " The synthesis of nanosized TiO2 powder with TiCl4," JOURNAL OF MATERIALS SCIENCE, vol. 35, pp. 4049-4054, 2000.
[24] 陳映羽, ''以自我複製技術設計及製作低損耗型波導'' 國立中央大學, 碩士論文, 民國101年。
[25] 盧宥任, 謝余松, 張益三, ''橢圓偏光術於ITO透明導電膜量測應用（下）'' 光連雙月刊, 99期, 58~64, May 2012。
[26] https://en.wikipedia.org/wiki/Atomic_force_microscopy#/media/
File:Atomic_force_microscope_block_diagram.svg
[27] 蕭添政, ''光子晶體於空間濾波器之應用'' 國立中央大學, 碩士論文, 民國97年。
[28] 簡智偉, ''具指向性微結構之設計'' 國立中央大學, 碩士論文, 民國97年。
[29] Lumerical Inc., " PML Boundary Condition," Lumerical FDTD on-line help.
[30] 陳沂蓉, ''奈米球微影術應用於建構奈米等級之二維金球陣列'' 清華大學奈米工程與微系統研究所, 碩士論文, 民國97年。