材料科学
锗
带隙
硒化物
氧化锗
半导体
氧化物
范德瓦尔斯力
剥脱关节
异质结
光伏
纳米技术
光电子学
石墨烯
化学
有机化学
分子
冶金
硅
生物
硒
光伏系统
生态学
作者
Danil W. Boukhvalov,Silvia Nappini,Mykhailo Vorokhta,Tevfik Onur Menteş,Lesia Piliai,Mohammad Panahi,Francesca Genuzio,Jessica De Santis,Chia‐Nung Kuo,C. S. Lue,Valentina Paolucci,Andrea Locatelli,Federica Bondino,Antonio Politano
标识
DOI:10.1002/adfm.202106228
摘要
Abstract Recently, germanium selenide (GeSe) has emerged as a promising van der Waals semiconductor for photovoltaics, solar light harvesting, and water photoelectrolysis cells. Contrary to previous reports claiming perfect ambient stability based on experiments with techniques without surface sensitivity, here, by means of surface‐science investigations and density functional theory, it is demonstrated that actually both: i) the surface of bulk crystals; and ii) atomically thin flakes of GeSe are prone to oxidation, with the formation of self‐assembled germanium‐oxide skin with sub‐nanometric thickness. Surface oxidation leads to the decrease of the bandgap of stoichiometric GeSe and GeSe 1− x , while bandgap energy increases upon surface oxidation of Ge 1− x Se. Remarkably, the formation of a surface oxide skin on GeSe crystals plays a key role in the physicochemical mechanisms ruling photoelectrocatalysis: the underlying van der Waals semiconductor provides electron–hole pairs, while the germanium‐oxide skin formed upon oxidation affords the active sites for catalytic reactions. The self‐assembled germanium‐oxide/germanium‐selenide heterostructure with different bandgaps enables the activation of photocatalytic processes by absorption of light of different wavelengths, with inherently superior activity. Finally, it is discovered that, depending on the specific solvent‐GeSe interaction, the liquid phase exfoliation of bulk crystals can induce the formation of Se nanowires.
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