The CZTSSe thin film was fabricated by chemical deposition method. Precursor solution was prepared by mixing metal acetate and thioacetamide in THF. Precursor solution deposited on Mo layer conducted $1^{st}$ and $2^{nd}$ heat treatment.
After the process, the physical properties of thin film were examined XRD, UV-vis, SEM, EDS and AES analysis. To analyze photovoltaic property CdS/i-ZnO/ZnO:Al/Al grid layer fabricated on the CZTSSe layer. The fabricated CZTSSe solar cell was performed 0.27% of conversion efficiency with 0.162 V of open circuit voltage, $4.78 mA/cm^2$ short circuit current density and 43% of fill factor.
For electrochemical $CO_2$ reduction, Cu pillar electrodes (Cu-2.5 h, Cu-5 h) were fabricated by using an electrodeposition method, which then catalytic activities and reaction mechanisms were investigated. The Cu-5 h electrode performed well with a 28 % Faradaic efficiency to formic acid at -0.5 V (vs. RHE). X-ray diffraction (XRD) analysis indicated that the enhanced catalytic activities were primarily attributable to the increased (111) facet, which is energetically favorable to produce HCOOH. Also, ultra violet photoelectron spectroscopy (UPS) and in situ electrochemical impedance spectroscopy (EIS) results suggested that the series of Cu pillar structure electrodes improved the electron transfer to adsorbed $CO_2$ due to the decreased work function of Cu pillar structure.
For the simultaneous electrochemical $CO_2$ reduction and water oxidation system, electrodeposited Ag dendrite and Co-Pi electrode were employed, respectively. Also, several reaction condition was tested to optimize $CO_2$ reduction rate and supplement of proton derived from water oxidation. Total $CO_2$ conversion which was started from -2.5 V in two electrode system produced carbon monoxide and oxygen at cathode and anode, respectively. The each reactions were maintain for 4 hours without pH change. The maximum faradaic efficiency of total $CO_2$ conversion showed 70 % at -2.8 V
전기화학적 이산화탄소 환원과 물산화 반응은 태양전지와 같은 재생에너지와 함께 연구되고 있다. 이러한 태양전지기반 전기화학적 이산화탄소 전환 시스템을 구축하기 위해서 다음과 같은 목표가 달성되어야 한다. i) 전기화학반응에 필요한 충분한 전압과 전류를 공급해야 한다. ii) 낮은 과전압 하에서 이산화탄소 환원 반응의 생성물 선택성이 있어야 한다. iii) 낮은 과전압하에서 물산화 반응이 일어나야 하며, 반응 생성물인 수소이온이 효율적으로 양극으로 전해져야 한다. 이 연구에서는 $Cu_2ZnSn(S,Se)_4$ (CZTSSe) 태양전지를 제작하고 태양전지 특성에 대한 연구를 진행하였다. 또한 이산화탄소 환원 반응을 위해 막대형태의 구리전극과 돌기형태의 은전극을 전기화학적으로 증착하고 그것의 촉매 특성에 대해서 분석하였다. 마지막으로 태양전지와의 융합 시스템을 만들기 위해, 물산화 촉매인 Co-Pi 전극을 전기화학적으로 증착한 후 물산화에 대한 촉매 특성을 평가하고 이산화탄소 환원반응과 연결하였을 때 촉매 특성의 변화에 대해서 고찰하였다
