有損中間層引介之光學效應於實現最大光穿透率至薄膜太陽能電池吸收層之研究; Investigation of Lossy-Film-Induced Optical Effects for Maximum Transmittance into Absorption Layers of Thin-Film Solar Cells

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/61465

Title:	有損中間層引介之光學效應於實現最大光穿透率至薄膜太陽能電池吸收層之研究;Investigation of Lossy-Film-Induced Optical Effects for Maximum Transmittance into Absorption Layers of Thin-Film Solar Cells
Authors:	賴啟勝;Lai,Chi-Sheng
Contributors:	光電科學與工程學系
Keywords:	太陽能電池;薄膜;穿透率;solar cell;thin film;transmittance
Date:	2013-08-28
Issue Date:	2013-10-08 15:12:57 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究探討有損中間層引介之光學效應對於實現最大光穿透率至薄膜太陽能電池吸收層之影響。使反射率產生相對低點之薄膜厚度設計其對應之穿透率並非相對極大。在第三章更進一步指出，以單一有損薄膜為例，當薄膜之消光係數逐漸增加時，反射率之最低點與進入吸收層之穿透率之最高點分別往膜層厚度較薄及膜厚較厚之位置移動。隨著入射角度增加，橫向電場與橫向磁場極化下，使得穿透率最大之最小膜厚值(不為零)，分別往高與低膜厚處。以銅銦鎵硒薄膜太陽能電池為例，因其中間層皆為有損材料在符合典型之尺寸設計規範下，可得以反射率最低作為其反射層設計之標準並不恰當，而應改以計算至吸收層之最大穿透率較為恰當。基於二、三章之結果，第四章以模擬熱退火最佳化演算法對銅銦鎵硒薄膜太陽能電池之中間層及抗反射層厚度與折射率，在同時考慮太陽光譜加權、各層材料之色散關係與大角度入射(0~80)下做最佳化設計。最佳化之結果顯示，以最佳化之目標函數為最小平均反射率(fR)時，摻鋁氧化鋅之厚度皆接近最佳化搜尋範圍之上限厚度；改目標函數為最大平均穿透率(fT)至吸收層時，摻鋁氧化鋅之厚度皆接近搜尋下限厚度。以最大穿透率至吸收層為目標函數之最佳化結果，在大於等於兩層抗反射層設計下，平均穿透率皆大於8%，平均反射率皆小於3.81%；相比以最小反射率為目標函數時，雖然平均反射率皆小於2.45%，但平均穿透率最大僅達57.36%。考慮太陽光譜與未考慮太陽光譜加權下之最佳化結果，無論在目標函數為fR或是fT時，一至三層抗反射層之角度平均反射率，在短波段時，具太陽光譜加權之角度平均反射率皆低於無太陽光譜加權之結果，而在長波段則呈現相反行為。若比較一至三層抗反射層下角度平均穿透率，則發現目標函數為fT時，具太陽光譜加權之角度平均穿透率明顯高於無太陽光譜加權之設計；而目標函數同為fR時，有無太陽光譜加權之角度平均穿透率並無明顯差別。 In this research, we investigate lossy-film-induced optical effects for a maximum average transmittance into absorption layers of thin-film solar cells. Using the transfer matrix method incorporated with the Poynting theorem successfully calculates optical transmittance passing through an arbitrary interface in multilayered structure. In a single lossy film case, we show that the film thickness at which the reflectance minimum occurs does not coincide at the same thickness as having a maximum transmittance. In general, when the extinction coefficient of the film is gradually increased, the reflectance minima moves toward smaller values of film thickness while the transmittance maximum shifts in the opposite direction. As the incident angle is increased, the maximum extinction coefficient at which the maximum transmittance still exists at a non-zero film thickness increases for TE waves. In contrast, TM waves behave just oppositlely. Since the interlayers of a typical CIGS solar cell are lossy, using minimum reflectance as the requirement of anti-reflection (AR) coating designs may not be appropriate. Instead, it should be the transmittance penetrating into the absorption layer that may be appropriate as the design criterion. Based on the results described in Chapters two and three, Chapter four reports the optimizations of interlayers and AR coating of a typical CIGS solar cell using simulated annealing (SA) algorithm incorporated with the solar irradiance spectrum for broadband (350 nm ~ 1200 nm) and omnidirectional (0~80) operations. The results show that using a target function of minimum reflectance, the thickness of AZO layer is close to the upper limit of the searching range used in SA. On the contrary, when the target function of maximum transmittance into the absorption layer is used, the AZO layer thickness is close to its lower limit. The optimized interlayers and two-layer AR coating with the maximum transmittance criterion exhibit an average transmittance of >80% and an average reflectance of <3.81%. In contrast, when a minimum reflectance requirement is used, the optimized results show an average reflectance of <2.45%, but the average transmittance is only 57.36%. When taking the solar spectrum weighting (SSW) into consideration, both target functions can result in a smaller reflectance and higher transmittance over the wavelengths with stronger solar irradiance, although the differences in the transmittance between designs with and without the SSW are subtle for the minimum reflectance designs due to a thicker AZO layer thickness.
Appears in Collections:	[Graduate Institute of Optics and Photonics] Electronic Thesis & Dissertation

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