石墨烯應用於染料敏化太陽能電池之研製
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2016
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本研究主要分為兩個目的，第一個主要是利用常壓化學氣相沉積法(Atmospheric pressure chemical vapor deposition, APCVD)在大面積銅箔(20 cm * 30 cm)成長出品質均勻之石墨烯。透過拉曼光譜分析已證實可成長出I2D/IG比值為2~4左右之單層石墨烯(Single-layer graphene, SLG)。若將製程優化，期望能應用在染料敏化太陽能電池(Dye-sensitized solar cell, DSSC)的電極。第二個目的是透過化鍍技術，在機械剝離法所製備高品質石墨烯表面複合鉑(Pt)及鉑釕合金(PtRu)奈米顆粒，並用來作為DSSC之對電極材料。藉由Pt及PtRu奈米顆粒之高比表面積(High specific surface area)，以及石墨烯與Pt之電極催化特性，以提升整體DSSC之轉換效率。化鍍製程是先將Pt之前驅物六氯鉑酸氫、釕前驅物氯化釕與石墨烯，加入還原劑乙二醇、緩衝溶液乙酸-氫氧化鈉，分別製作出石墨烯/Pt及石墨烯/PtRu複合材料，並將複合材料滴佈於導電玻璃基板上形成對電極。本研究所製備出之複合材料透過SEM、EDS及TEM量測，證實已成功將Pt及PtRu均勻複合於石墨烯表面，從結果得知石墨烯/Pt粒徑分布為1.5 nm~5.0 nm，平均在3.5 nm~4.0 nm占最多，其平均電阻值為2.73 Ω；而石墨烯/PtRu粒徑則是分布在2~4 nm，平均在2.5 nm占最多，其平均電阻值為6.44 Ω。經封裝組合成DSSC元件後，比較濺鍍法製備Pt膜、單純石墨烯膜、石墨烯/Pt及石墨烯/PtRu四種電極的轉換效率，分別為1.52 %、0.64 %、2.08 %、1.35 %。實驗結果顯示，石墨烯結合Pt後因為電性及催化特性較好，因此具有較高轉換效率，而在石墨烯/PtRu的部分也接近使用濺鍍法製備Pt膜所得到之轉換效率，透過簡易化鍍方法來製備複合材料，可減少製程所需成本，以及提升整體DSSC之轉換效率。
This study has two major research objectives: (1) Large-area and uniform synthesis of graphene on copper foil (20 cm * 30 cm) by atmospheric pressure chemical vapor deposition. In Raman spectroscopy, the I2D/IG ratio are 2~4 for the single-layer graphene (SLG). If the process to be improved, it can be applied in electrode of dye-sensitized solar cells (DSSC). (2) In the second objective, the chemical plating techniques is used to composite Pt nanoparticles (NPs) and PtRu NPs on high-quality graphene as the electrode of DSSC. Due to the Pt and PtRu NPs with high specific surface and graphene/Pt with high electrocatalytic activity, the conversion efficiency of the DSSC can be increased. Firstly, the H2PtCl6•6H2O and RuCl3 are dissolved in ethylene glycol and acetic acid-sodium hydroxide buffer solution, followed by dip-coating on FTO to form electrode. The SEM, EDS, and TEM measurements were carried out to characterize the hybrid materials. The results indicate that the Pt NPs size is in range of 1.5~5 nm, with an average size of 3.5~4.0 nm and PtRu NPs size is in range of 2~4 nm, with an average size of 2.5 nm. The average resistance of graphene/Pt and graphene/PtRu are 2.73 Ω and 6.44 Ω. The DSSC based on the sputtered Pt, graphene, graphene/pt and graphene/PtRu counter electrode achieved a power conversion efficiency of 1.52 %, 0.64 %, 2.08 %, 1.35 % under AM1.5 illumination of 100 mW cm−2, as a result, the graphene/Pt has highest conversion efficiency, which is due to that the graphene/Pt counter electrode has higher conductivity and better electrocatalytic activity for I3 −/I− redox reaction, and then the graphene/PtRu counter electrode has the conversion efficiency of 1.35 %, which is close to the conversion efficiency of sputtered Pt. The results demonstrate that the method with low cost and simple can improve the performance of DSSC.
This study has two major research objectives: (1) Large-area and uniform synthesis of graphene on copper foil (20 cm * 30 cm) by atmospheric pressure chemical vapor deposition. In Raman spectroscopy, the I2D/IG ratio are 2~4 for the single-layer graphene (SLG). If the process to be improved, it can be applied in electrode of dye-sensitized solar cells (DSSC). (2) In the second objective, the chemical plating techniques is used to composite Pt nanoparticles (NPs) and PtRu NPs on high-quality graphene as the electrode of DSSC. Due to the Pt and PtRu NPs with high specific surface and graphene/Pt with high electrocatalytic activity, the conversion efficiency of the DSSC can be increased. Firstly, the H2PtCl6•6H2O and RuCl3 are dissolved in ethylene glycol and acetic acid-sodium hydroxide buffer solution, followed by dip-coating on FTO to form electrode. The SEM, EDS, and TEM measurements were carried out to characterize the hybrid materials. The results indicate that the Pt NPs size is in range of 1.5~5 nm, with an average size of 3.5~4.0 nm and PtRu NPs size is in range of 2~4 nm, with an average size of 2.5 nm. The average resistance of graphene/Pt and graphene/PtRu are 2.73 Ω and 6.44 Ω. The DSSC based on the sputtered Pt, graphene, graphene/pt and graphene/PtRu counter electrode achieved a power conversion efficiency of 1.52 %, 0.64 %, 2.08 %, 1.35 % under AM1.5 illumination of 100 mW cm−2, as a result, the graphene/Pt has highest conversion efficiency, which is due to that the graphene/Pt counter electrode has higher conductivity and better electrocatalytic activity for I3 −/I− redox reaction, and then the graphene/PtRu counter electrode has the conversion efficiency of 1.35 %, which is close to the conversion efficiency of sputtered Pt. The results demonstrate that the method with low cost and simple can improve the performance of DSSC.
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石墨烯, 染料敏化太陽能電池, 化鍍技術, 鉑釕合金, graphene, dye-sensitized solar cells, chemical plating, PtRu