傳統光電化學太陽能電池採用塗佈含白金溶液或以電化學沉積白金量子點在n型單晶矽，可以產生開路光電壓達0.65 伏特和光電轉換效率亦達14.5 %，影響此光電化學電池的重要機制為白金量子點大小與密度分佈。 本論文經由下述實驗，成功採用物理氣相沉積方法製備出利用白金量子點的光電化學太陽能電池，其光電轉換效率達4%，開路電壓達0.35伏特。首先對光電化學太陽能電池元件中的ITO玻璃，上面的白金薄膜厚度做探討，以得到最大的入射光與光電轉換效率。再分別對蒸鍍與濺鍍系統所製成的薄膜均勻性了解，可以得知電子槍蒸鍍系統所得到的薄膜較為鬆散，利於形成白金量子點。故使用蒸鍍系統鍍製不同薄膜厚度並搭配不同溫度的熱處理調整，可以使得白金量子點大小介於5~100nm，並可以發現不同的白金量子點大小對轉換效率會有不同影響，而且薄膜厚度越薄，內聚形成量子點所需溫度越低，光電轉換效率極值出現溫度越低，但以此製程製備出的光電轉換效率有極限值4%。再配合半導體微影技術來定義圖形以調控白金量子點密度在1011~109(白金量子點大小在10奈米以下的個數)/平方公分。透過上述的微影製程，在白金量子點大小為10奈米以下，平均密度在每平方公分具有1.43 x 1015白金量子點個數，可以得到光電轉換效率2%，開路電壓在0.35伏特。 Platinum solution coating or electrochemical deposition platinum quantum dots in n-type silicon is employed on traditional Photoelectrochemical solar cell, which make open-voltage of 0.65 volts and photoelectric conversion efficiency of 14.5 percent achieved. The impacts on the important mechanisms of the Photoelectrochemical cell depend on platinum quantum dot size and density distribution. In this thesis, the platinum quantum dot of utilizing physical vapor deposition method on Photoelectrochemical solar cells is adopted and makes photoelectric conversion efficiency of 4%, open circuit voltage of 0.35 volts. First, the thickness of platinum film on the ITO glass of solar cells is considered to reach the maximum of incident intensity and photoelectric conversion efficiency. The uniformity of platinum thin film made of evaporation and sputtering system is analyzed, respectively. With electron gun evaporation system, it would be beneficial to form quantum dots from platinum owing to its loose composition. Therefore, with the modulation of platinum film thickness in evaporation system and annealing temperature, the platinum quantum dot size can be controlled between 5 ~ 100 nm. It can be found that size of platinum quantum dot plays an important role on the conversion efficiency. And the thinner thickness of film is, the lower temperature would be required at forming quantum dot where the maximum of conversion efficiency occurs. There exists the maximum photoelectric conversion efficiency with 4% under this fabrication process. With the pattern definition by semiconductor lithography technology, the platinum quantum dot density can be controlled in 109 ~1011 (the amount of Platinum quantum dot with the size below 10 nm) / cm2. By the lithography process as mentioned above, the photoelectric conversion efficiency of 2% and the open circuit voltage of 0.35 volts can be achieved with the platinum quantum dot size below 10 nm and the platinum quantum dot density of 1.43 x 1015 /cm2 at average.
