Feng Jianyong, Cao Dapeng, Wang Zhiqiang, Luo Wenjun, Wang Jiajia, Li Zhaosheng, Zou Zhigang
National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Ecomaterials and Renewable Energy Research Center, Nanjing University, 22 Hankou Road, Nanjing 210093 (P.R. China).
Chemistry. 2014 Dec 1;20(49):16384-90. doi: 10.1002/chem.201402760. Epub 2014 Oct 14.
Ta3 N5 is a promising photoanode candidate for photoelectrochemical water splitting, with a band gap of about 2.1 eV and a theoretical solar-to-hydrogen efficiency as high as 15.9 % under AM 1.5 G 100 mW cm(-2) irradiation. However, the presently achieved highest photocurrent (ca. 7.5 mA cm(-2) ) on Ta3 N5 photoelectrodes under AM 1.5 G 100 mW cm(-2) is far from the theoretical maximum (ca. 12.9 mA cm(-2) ), which is possibly due to serious bulk recombination (poor bulk charge transport and charge separation) in Ta3 N5 photoelectrodes. In this study, we show that volatilization of intentionally added Ge (5 %) during the synthesis of Ta3 N5 promotes the electron transport and thereby improves the charge-separation efficiency in bulk Ta3 N5 photoanode, which affords a 320 % increase of the highest photocurrent comparing with that of pure Ta3 N5 photoanode under AM 1.5 G 100 mW cm(-2) simulated sunlight.
Ta3 N5是一种很有前景的用于光电化学水分解的光阳极候选材料，其带隙约为2.1电子伏特，在AM 1.5 G 100毫瓦·平方厘米(-2)光照下理论太阳能到氢能的效率高达15.9%。然而，目前在Ta3 N5光电极上，在AM 1.5 G 100毫瓦·平方厘米(-2)条件下实现的最高光电流（约7.5毫安·平方厘米(-2)）远低于理论最大值（约12.9毫安·平方厘米(-2)），这可能是由于Ta3 N5光电极中严重的体相复合（体相电荷传输和电荷分离较差）。在本研究中，我们表明在Ta3 N5合成过程中故意添加的Ge（5%）的挥发促进了电子传输，从而提高了体相Ta3 N5光阳极中的电荷分离效率，与纯Ta3 N5光阳极相比，在AM 1.5 G 100毫瓦·平方厘米(-2)模拟阳光下，其最高光电流提高了320%。
