Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016)
    Nanomaterials Tuesday Sessions
       Session NM-TuP

Paper NM-TuP3
Understanding Ligand-Surface Passivation of Cation-Rich Colloidal Quantum Dots: First-Principles Study

Tuesday, December 13, 2016, 4:00 pm, Room Mauka

Session: Nanomaterials Poster Session
Presenter: Yong-Hyun Kim, Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea
Authors: J.-H. Ko, Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea
D. Yoo, Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea
Y.-H. Kim, Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea
Correspondent: Click to Email
Colloidal quantum dots (CQDs) are attractive nanomaterials for optoelectronic and photovoltaic applications because they are useful for mass production and easy to tune optical and electronic properties by controlling the size of CQDs. Generally, stable CQDs with good ligand-surface passivation are essential for such CQD applications. Yet, microscopic understanding how CQD surfaces are stabilized with passivating ligands is not clear in the colloidal environment. In this study, we performed first-principles density-functional theory (DFT) calculations for understanding ligand-surface passivation of cation-rich surfaces of IV-VI, II-VI, and III-V CQDs. Calculation results indicate that while non-polar surfaces of CQDs are self-passivated, polar surfaces of cation-rich CQDs, i.e., (100) and (111) for zinc blende semiconductors, have reactive surface dangling electrons that should be properly coordinated with passivating anionic ligands. We will discuss how such polar surfaces of CQDs could be stabilized by organic and inorganic ligands based on electron counting rule and coordination chemistry.