因應高溫型太陽能選擇性吸收膜(High temperature SSCs)的需求，吾等利用磁控共濺鍍設備，成功沈積添加金屬鉻或鎳及鎢於碳化鈦中形成碳化固溶體(Cr-W-TiC or Ni-W-TiC)在不鏽鋼基板上。研究發現鉻-鎢-鈦碳化固溶體((Cr, W, Ti)C1-x)在退火後有奇特的現象，薄膜中的鉻及鎢含量，能以靶功率大小進行調控。分析包括XRD繞射、AFM原子力顯微鏡量測厚度與表面形貌、TEM高解析截面、反射率光譜等，在其光學效能優化的同時，亦研究了其特殊氧化鉻鈦層產生之效應對薄膜光學性質的關聯性；探討不同金屬鉻鎢比例，對其結晶性、晶粒尺寸與晶界比例所對應的擴散對氧化鉻鈦層的影響。
在紅外線反射層，鎢層，及抗反射層，氧化矽，都沉積完後，完整結構如下：SS/ W/ Cr-W-TiC/ (Cr0.88Ti0.12)2O3/ SiO2，在最佳化後依靠折射漸變，太陽能吸收率高達95.0%，且熱放射率僅有9.4%，太陽能選擇性高達10.11。除此之外，熱穩定性的研究以空氣下退火來進行，控制不同的退火溫度和時間，來展現薄膜對不同高溫環境的穩定。如48小時600°C和2小時700°C的退火，此SSC仍能維持93.7-94.1%的高吸收率，以及10.0-10.8%的熱放射率，且於XRD和TEM分析中無其他明顯改變，足以說明其極佳的熱穩定性。

As the working temperature of concentrating solar power (CSP) continues to increase for higher efficiency, the requirement for solar selective coatings is becoming more urgent. Here we report strong carbon-affinity Cr-W-Ti carbide solar selective coatings deposited on stainless steel and silicon substrates using a magnetron co-sputtering technique. The target element and the target power were varied to obtain TiC / Ni-W-TiC / Cr-W-TiC carbides having different characteristics. The structure, morphology and optical properties have been characterized by X-ray diffractometry (XRD), Atomic Force Microscope (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis optical spectroscopy (UV-vis). Selected Cr-W-Ti carbide coating can form (Cr, W, Ti)C1-x solid solution carbide and multifunctional oxide (Cr0.88Ti0.12)2O3 will emerge on surface after annealing. Then it was used to make multilayered W/ Cr-W-TiC/ (Cr0.88Ti0.12)2O3/ SiO2 where W and SiO2 served as the IR reflector and anti-reflection layers, respectively. The solar absorptance and thermal emission were determined with a high absorptance of 95% and a low emittance of 9.4%. Thermal stability was checked by annealing the samples in air at 600°C for 48 hours and 700°C for 2 hours.

1.Carrillo, A.J., et al., Solar energy on demand: a review on high temperature thermochemical heat storage systems and materials. Chemical reviews, 2019. 119(7): p. 4777-4816.
2.Romero, M. and J. González‐Aguilar, Solar thermal CSP technology. Wiley Interdisciplinary Reviews: Energy and Environment, 2014. 3(1): p. 42-59.
3.Tabor, H., Selective radiation. i. wavelength discrimination. ii. wavefront discrimination. Bull. Res. Counc. Isr., Sect. C, 1956. 5(2).
4.Selvakumar, N. and H.C. Barshilia, Review of physical vapor deposited (PVD) spectrally selective coatings for mid-and high-temperature solar thermal applications. Solar energy materials and solar cells, 2012. 98: p. 1-23.
5.Toth, L., Transition metal carbides and nitrides. 2014: Elsevier.
6.Babu, D.D., Design and Development of New Indole Based Sensitizers for Dye Sensitized Solar Cells. 2016, National Institute of Technology Karnataka, Surathkal.
7.Fox, M., Optical properties of solids. 1970, Oxford University Press, Oxford Master Series in Physics (Book 3).
8.Moon, J., et al., High performance multi-scaled nanostructured spectrally selective coating for concentrating solar power. Nano Energy, 2014. 8: p. 238-246.
9.Chaanaoui, M., S. Vaudreuil, and T. Bounahmidi, Benchmark of concentrating solar power plants: Historical, current and future technical and economic development. Procedia Computer Science, 2016. 83: p. 782-789.
10.Ibrahim, K., et al., Solar selective performance of metal nitride/oxynitride based magnetron sputtered thin film coatings: a comprehensive review. Journal of Optics, 2018. 20(3): p. 033001.
11.Kennedy, C.E., Review of mid-to high-temperature solar selective absorber materials. 2002, National Renewable Energy Lab., Golden, CO.(US).
12.Cao, F., et al., A review of cermet-based spectrally selective solar absorbers. Energy & Environmental Science, 2014. 7(5): p. 1615-1627.
13.Pettit, R., R. Sowell, and I. Hall, Black chrome solar selective coatings optimized for high temperature applications. Solar Energy Materials, 1982. 7(2): p. 153-170.
14.Fan, J.C. and S.A. Spura, Selective black absorbers using rf‐sputtered Cr2O3/Cr cermet films. Applied Physics Letters, 1977. 30(10): p. 511-513.
15.Teixeira, V., et al., Spectrally selective composite coatings of Cr–Cr2O3 and Mo–Al2O3 for solar energy applications. Thin solid films, 2001. 392(2): p. 320-326.
16.Nunes, C., et al., Graded selective coatings based on chromium and titanium oxynitride. Thin Solid Films, 2003. 442(1-2): p. 173-178.
17.Yin, Y., et al., Direct current reactive sputtering Cr–Cr2O3 cermet solar selective surfaces for solar hot water applications. Thin Solid Films, 2009. 517(5): p. 1601-1606.
18.Sathiaraj, T.S., et al., Optical properties of selectively absorbing rf sputtered Ni Al2O3 composite films. Thin Solid Films, 1991. 195(1-2): p. 33-42.
19.Xinkang, D., et al., Microstructure and spectral selectivity of Mo–Al2O3 solar selective absorbing coatings after annealing. Thin Solid Films, 2008. 516(12): p. 3971-3977.
20.Antonaia, A., et al., Stability of W-Al2O3 cermet based solar coating for receiver tube operating at high temperature. Solar Energy Materials and Solar Cells, 2010. 94(10): p. 1604-1611.
21.Wuchina, E., et al., UHTCs: ultra-high temperature ceramic materials for extreme environment applications. The Electrochemical Society Interface, 2007. 16(4): p. 30.
22.Coulibaly, M., et al., From colloidal precursors to metal carbides nanocomposites MC (M= Ti, Zr, Hf and Si): synthesis, characterization and optical spectral selectivity studies. Solar Energy Materials and Solar Cells, 2015. 143: p. 473-479.
23.Gao, X.-H., et al., Structure, optical properties and thermal stability of TiC-based tandem spectrally selective solar absorber coating. Solar Energy Materials and Solar Cells, 2016. 157: p. 543-549.
24.Gao, X.-H., et al., Enhanced thermal stability and spectral selectivity of SS/TiC-Y/Al2O3 spectrally selective solar absorber by thermal annealing. Solar Energy, 2016. 140: p. 199-205.
25.Wei, Q., et al., High temperature spectral selective TiC-Ni/Mo cermet-based coatings for solar thermal systems by laser cladding. Solar Energy, 2018. 171: p. 247-257.
26.Gao, X.-H., et al., Microstructure, chromaticity and thermal stability of SS/TiC-WC/Al2O3 spectrally selective solar absorbers. Solar Energy Materials and Solar Cells, 2017. 164: p. 63-69.
27.Gao, X.-H., et al., Structure, optical properties and thermal stability of SS/TiC–ZrC/Al 2 O 3 spectrally selective solar absorber. RSC advances, 2016. 6(68): p. 63867-63873.
28.Ordal, M.A., et al., Optical properties of Al, Fe, Ti, Ta, W, and Mo at submillimeter wavelengths. Applied optics, 1988. 27(6): p. 1203-1209.
29.Sárosi, Z., et al., Evaluation of reflectivity of metal parts by a thermo-camera. InfraMation 2010 proceedings, 2010: p. 475-486.
30.Trindade, B., M. Vieira, and E. Bauer-Grosse, Amorphous phase forming ability in (W–C)-based sputtered films. Acta materialia, 1998. 46(5): p. 1731-1739.
31.Koutzaki, S.H., J.E. Krzanowski, and J.J. Nainaparampil, Phase formation and microstructure in sputter-deposited Ti-Mo-C and Ti-WC thin films. Metallurgical and Materials Transactions A, 2002. 33(6): p. 1579-1588.
32.Sibin, K., S. John, and H.C. Barshilia, Control of thermal emittance of stainless steel using sputtered tungsten thin films for solar thermal power applications. Solar energy materials and solar cells, 2015. 133: p. 1-7.
33.Jansson, U. and E. Lewin, Sputter deposition of transition-metal carbide films—A critical review from a chemical perspective. Thin Solid Films, 2013. 536: p. 1-24.
34.Furlan, A., et al., Control of crystallinity in sputtered Cr–Ti–C films. Acta Materialia, 2013. 61(17): p. 6352-6361.
35.Matsuoka, J., et al., Temperature dependence of refractive index of SiO2 glass. Journal of non-crystalline solids, 1991. 135(1): p. 86-89.
36.Gao, L., F. Lemarchand, and M. Lequime, Refractive index determination of SiO2 layer in the UV/Vis/NIR range: spectrophotometric reverse engineering on single and bi-layer designs. Journal of the European Optical Society-Rapid publications, 2013. 8.
37.Farooq, M., A. Green, and M. Hutchins, High performance sputtered Ni: SiO2 composite solar absorber surfaces. Solar energy materials and solar cells, 1998. 54(1-4): p. 67-73.
38.Yang, J., et al., Air-Stability Improvement of Solar Selective Absorbers Based on TiW–SiO2 Cermet up to 800° C. ACS Applied Materials & Interfaces, 2021. 13(12): p. 14587-14598.
39.Window, B. and N. Savvides, Charged particle fluxes from planar magnetron sputtering sources. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1986. 4(2): p. 196-202.
40.Chapman, B.N., Glow discharge processes: sputtering and plasma etching. 1980: Wiley.
41.Thornton, J.A., The microstructure of sputter‐deposited coatings. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1986. 4(6): p. 3059-3065.
42.Goldstein, J.I., et al., Scanning electron microscopy and X-ray microanalysis. 2017: Springer.
43.Inkson, B., Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for materials characterization, in Materials characterization using nondestructive evaluation (NDE) methods. 2016, Elsevier. p. 17-43.
44.Farooq, M. and Z. Lee, Computations of the optical properties of metal/insulator-composites for solar selective absorbers. Renewable Energy, 2003. 28(9): p. 1421-1431.
45.Schneider, B.W., et al., Pyramidal surface textures for light trapping and antireflection in perovskite-on-silicon tandem solar cells. Optics express, 2014. 22(106): p. A1422-A1430.
46.Hallström, S., et al., High temperature oxidation of chromium: Kinetic modeling and microstructural investigation. Solid State Ionics, 2013. 240: p. 41-50.
47.Linstrom, P.J. and W.G. Mallard, The NIST Chemistry WebBook: A chemical data resource on the internet. Journal of Chemical & Engineering Data, 2001. 46(5): p. 1059-1063.
48.Wen, C.-D. and I. Mudawar, Modeling the effects of surface roughness on the emissivity of aluminum alloys. International journal of heat and mass transfer, 2006. 49(23-24): p. 4279-4289.
49.Jyothi, J., et al., Measurement of high temperature emissivity and photothermal conversion efficiency of TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO spectrally selective coating. Solar Energy Materials and Solar Cells, 2017. 171: p. 123-130.
50.Heiroth, S., et al., Optical and mechanical properties of amorphous and crystalline yttria-stabilized zirconia thin films prepared by pulsed laser deposition. Acta Materialia, 2011. 59(6): p. 2330-2340.
51.Gavrushko, V., et al. On refractive index of optical radiation of polycrystalline silicon films. in Journal of Physics: Conference Series. 2020. IOP Publishing.
52.Aarik, J., et al., Effect of crystal structure on optical properties of TiO2 films grown by atomic layer deposition. Thin Solid Films, 1997. 305(1-2): p. 270-273.