硫系化合物
纳米颗粒
密度泛函理论
钝化
材料科学
氢
化学计量学
兴奋剂
化学物理
纳米技术
杂质
带隙
吸附
无机化学
化学
计算化学
物理化学
光电子学
有机化学
图层(电子)
作者
Márton Vörös,Nicholas P. Brawand,Giulia Galli
标识
DOI:10.1021/acs.chemmater.6b04126
摘要
Lead chalcogenide (PbX) nanoparticles are promising materials for solar energy conversion. However, the presence of trap states in their electronic gap limits their usability, and developing a universal strategy to remove trap states is a persistent challenge. Using calculations based on density functional theory, we show that hydrogen acts as an amphoteric impurity on PbX nanoparticle surfaces; hydrogen atoms may passivate defects arising from ligand imbalance or off-stoichiometric surface terminations irrespective of whether they originate from cation or anion excess. In addition, we show, using constrained density functional theory calculations, that hydrogen treatment of defective nanoparticles is also beneficial for charge transport in films. We also find that hydrogen adsorption on stoichiometric nanoparticles leads to electronic doping, preferentially n-type. Our findings suggest that postsynthesis hydrogen treatment of lead chalcogenide nanoparticle films is a viable approach to reduce electronic trap states or to dope well-passivated films.
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