本論文利用化學浴沉積法於ITO導電玻璃上沉積Ag-In-S-Se四元化合物光電極薄膜，並將之應用於光電化學產氫系統；就製程而言，化學浴沉積法具備便宜、簡單以及可大面積製備的優點，就材料而言，Ag-In-S-Se四元化合物可吸收紫外光與可見光波段的能量，因此極具有發展潛力。本研究將改變前驅物比例、水浴溫度、ph值、鍍層層數、磁石轉速、熱處理溫度以及硒的摻雜比例，用以探討薄膜的晶體結構、表面型態、光學以及光電化學性質。由XRD與EDS分析得知[Ag+]/[In3+] =1/5時可製備出AgIn5S8的結構，接著透過硒元素的摻雜後，使其轉變成AgIn5S8-xSex四元化合物，其直接能隙值由1.79 eV降至約1.75~ 1.786 eV之間，經由Mott-schottky量測得知其皆為n型半導體，其平帶電壓由-0.78 V增加至-0.93 V(vs. Ag/AgCl)，而其載子濃度分別為2.58×10^10 cm-3以及2.83×10^12 cm-3，在光電流量測當中，使用0.25M K2SO3和0.35M Na2S當作犧牲試劑，於100 mW/cm2(AM 1.5G)的模擬太陽光照射下，其所量測到之光電流值分別為0.8 mA/cm2以及1.15 mA/cm2。另外於穩定性測試當中，將TiO2光電極薄膜覆蓋於AgIn5S8-xSex光電極薄膜層上，其可有效地減緩光腐蝕的現象，使光電流值減少3.57%的衰退。 Chemical bath deposition (CBD) is applied to deposit Ag-In-S-Se quaternary compound photoelectrode thin film on indium tin oxide coated glass (ITO), which can then be used as the photoelectrode in photoelectrochemical production of hydrogen. The advantages of chemical bath deposition are simple, inexpensive and large area deposition. Besides, Ag-In-S-Se quaternary compound can absorb ultraviolet and visible light so that it has potential to develope. In our experiment, we investigate the crystal structure, morphology, optic property, and PEC performance as precursor ratio, bath temperature, ph value, number of thin film, stirring rate, thermal treatment temperature and atomic percentage of selenium are changed. The results of XRD and EDS show that AgIn5S8 is obtained when [Ag+]/[In3+] =1/5 and transformed to AgIn5S8-xSex quaternary compound by doping selenium with the direct band gap decreasing from 1.79 eV to the range of 1.75~1.786 eV. Both are identified as n-type semiconductor according to Mott-Schottky measurement with decreasing flat band potential from -0.78 V to -0.93 V(vs. Ag/AgCl) and increasing carrier density from 2.58×10^10 cm-3 to 2.83×10^12 cm-3. In PEC measurement, we use 0.25M K2SO3 and 0.35M Na2S as sacrificial reagent and 100 mW/cm2(AM 1.5G) simulation sunlight as light source. The photocurrent density of AgIn5S8 and AgIn5S7.992Se0.008 is 0.8 mA/cm2 and 1.15 mA/cm2 with an external voltage of 0V(vs. Ag/AgCl) respectively. Moreover, the result of stability test shows that photocorrosion phenomenon is inhibited by covering TiO2 on AgIn5S8-xSex photoelectrode thin film, and reduces 3.57% decay of photocurrent density.
