研究目的
To develop transparent Ta3N5 photoanodes for efficient oxygen evolution in photoelectrochemical water splitting, enabling the construction of tandem cells for overall water splitting without external power supply.
研究成果
Transparent Ta3N5 photoanodes on GaN/Al2O3 substrates achieved a high photocurrent density of 6.3 mA cm-2 at 1.23 V vs. RHE and a maximum HC-STH of 1.15%, with excellent transparency above 600 nm. The tandem cell exhibited an initial STH greater than 7%, but stability issues need addressing for practical use. The GaN layer enhances carrier collection, and further investigations could lead to improved nitride-based photoanodes.
研究不足
The durability of the tandem cell is insufficient for practical applications, as the STH efficiency decreases significantly over time, possibly due to self-oxidation of Ta3N5 forming an insulating layer. The photocurrent also decreases gradually during operation.
1：Experimental Design and Method Selection:
The study aimed to fabricate transparent Ta3N5 photoanodes on GaN/Al2O3 substrates using high-temperature nitridation in NH3 atmosphere, based on previous methods. Theoretical analysis of electronic band structure was conducted using a semiconductor device simulator.
2：Sample Selection and Data Sources:
Ta3N5 thin films were prepared on n-type GaN-coated double-side-polished sapphire substrates (GaN/Al2O3), as well as on quartz (SiO2) and bare sapphire (Al2O3) for comparison. CuInSe2 (CIS)-based thin-film solar cells were provided by Solar Frontier K.K.
3：List of Experimental Equipment and Materials:
Equipment includes facilities for high-temperature processing, UV-vis spectrophotometer for transmittance measurements, X-ray diffractometer (XRD) for crystallographic analysis, scanning electron microscope (SEM) for imaging, and photoelectrochemical (PEC) measurement setup with simulated sunlight (AM 1.5G, 1 sun). Materials include Ta precursor compounds, NH3 gas, NiFeOx catalyst, potassium phosphate aqueous solution (pH 13), and Pt/Ni electrodes.
4：5G, 1 sun). Materials include Ta precursor compounds, NH3 gas, NiFeOx catalyst, potassium phosphate aqueous solution (pH 13), and Pt/Ni electrodes.
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: Ta3N5 films were fabricated by heating Ta precursors in NH3 at high temperatures (~1000°C). NiFeOx catalyst was deposited on the surface. PEC measurements were performed in 0.2 M potassium phosphate solution (pH 13) under simulated sunlight, with i-E curves, IPCE, gas evolution, and STH efficiency recorded. A tandem cell was constructed with the photoanode and a series-connected dual-CIS cathode.
5：2 M potassium phosphate solution (pH 13) under simulated sunlight, with i-E curves, IPCE, gas evolution, and STH efficiency recorded. A tandem cell was constructed with the photoanode and a series-connected dual-CIS cathode.
Data Analysis Methods:
5. Data Analysis Methods: Data analysis involved calculating photocurrent densities, HC-STH, IPCE, faradaic efficiency, and STH. Theoretical simulations of band structure and i-E curves were performed using semiconductor equations.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
