臺灣博碩士論文加值系統

本篇論文將氧化石墨烯應用於單晶矽PN太陽能電池上，希望可以利用氧化石墨烯帶有負電荷的特性作為鈍化層以降低表面復合率以提升效率。

首先我們仿照前人經驗直接將氧化石墨烯塗佈於P型矽來減少少數載子(電子)的表面復合機率，但在多次實驗後發現短路電流有明顯下降的趨勢而導致效率無法提升。為了找出原因，我們先是確認氧化石墨烯是否會阻礙鋁背電場的形成，利用鋁背電場層與原本P型矽層的被蝕刻速率的差異，我們可以用掃描式電子顯微鏡看到背電場的深度，無論是否有加入氧化石墨烯的樣品我們都可以看到完整的鋁背電場層。

隨後我們將目標轉向了製程溫度對氧化石墨烯的影響，我們利用Sinton WCT-120來進行了不同製程溫度或是不同氣體環境的少數載子生命週期的量測，發現氧化石墨烯的鈍化能力會隨著製程溫度的提高而有著顯著的下降，而氣體環境雖說有著一定的影響但並無溫度所造成的退化來的明顯。

因此，為了避免溫度對氧化石墨烯鈍化能力造成下降，我們採用了雙面太陽能電池的結構，使得氧化石墨烯得以在最外層，而避免經過高溫的熱退火製程，最後藉由塗佈方式的改良，我們只要能避免氧化石墨烯覆蓋導電極，就可以避免電流的下降而得到太陽能電池轉換效率的提升。

In this study, we have used graphene oxide, which has the characteristics of negative charge, to apply on single-crystal silicon PN solar cells. It was expected that the graphene oxide could be use as passivation layer to reduce surface recombination rate and improve the efficiency of solar cells.

We have coated graphene oxide on the p-type silicon to reduce the surface recombination rate of minority carriers (electrons). We found that the short-current current significantly decreases and could not lead to efficiency improvement. In order to find out the reason, we first confirm whether the graphene oxide will impede the formation of aluminum back surface field. Because of different etching rates of aluminum back surface field layer and original P-type silicon layer, we can use scanning electron microscopy to see the back electric field. Both the sample coated or not coated by graphene oxide showed obvious aluminum back electric field layer.

We then focused on the effects of the process temperature on graphene oxide. We used Sinton WCT-120 to measure the minority carrier lifetime with different process temperatures or different ambience. It was found that the passivation ability of graphene oxide will degrade with the temperature rising, while the ambience has the certain impact but not as obvious as the temperature.

In order to avoid decreasing the passivation ability of graphene oxide, we have adopted the structure of bifacial solar cells, so that the graphene oxide can act as the outermost layer to prevent the graphene oxide suffering from high temperature treatment. With the improvement of the coating method, we can avoid the precipitation of graphene oxide on busbar and the current can flow well. Finally, we can improve the conversion efficiency.

致謝 I
摘要 III
Abstract V
目錄 VII
圖目錄 IX
表目錄 XIII
第一章 緒論 1
1.1前言 1
1.2研究動機 3
1.3論文架構 4
第二章 原理及文獻探討 5
2.1 太陽能電池運作原理 5
2.1.1 太陽能電池結構 5
2.1.2 光伏效應 6
2.1.3 太陽能電池效率相關參數 8
2.2 太陽能電池的鈍化機制 10
2.2.1 載子復合機制 10
2.2.2鋁背電場(Back Surface Field)的形成 12
2.2.3 鈍化層(Passivation Layer)作用 13
2.3 氧化石墨烯特性介紹 15
2.3.1氧化石墨烯材料特性 15
2.3.2氧化石墨烯製備原理 16
2.3.3氧化層電荷 17
第三章 氧化石墨烯太陽能電池製作 21
3.1 太陽能電池實作 21
3.1.1 實驗流程 22
3.1.2 實驗結果與討論 24
3.2 確認鋁背電場的形成 26
3.2.1 實驗流程 26
3.2.2 熱退火參數對鋁背電場的影響 27
第四章 氧化石墨烯高溫鈍化特性衰退 33
4.1不同溫度氧化石墨烯少數載子生命週期研究 33
4.1.1 實驗流程 33
4.1.2 少數載子生命週期量測儀量測流程 35
4.1.3 實驗結果與討論 41
4.2有氧與無氧環境下氧化石墨烯少數載子生命週期量測 43
4.2.1 兩段式變換氣體流程 43
4.2.2 實驗結果與討論 45
第五章 非高溫製程氧化石墨烯於單晶矽太陽能電池應用 49
5.1 非高溫製程氧化石墨烯太陽能電池製作 49
5.1.1 非高溫製程氧化石墨烯太陽能電池結構 49
5.1.2 實驗流程 51
5.2 實驗結果與討論 53
5.2.1 不同滴定方式氧化石墨烯雙面太陽能電池效率 53
5.2.2 噴槍法塗佈氧化石墨烯雙面太陽能電池效率 57
第六章 總結和未來方向 61
6.1 總結 61
6.2 未來方向 63
參考文獻 65

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