Halide-Amine Co-Passivated Indium Phosphide Colloidal Quantum Dots in Tetrahedral Shape

• Published in: Angewandte Chemie International Edition Vol. 55; no. 11; pp. 3714 - 3718
• Main Authors: Kim, Kyungnam, Yoo, Dongsuk, Choi, Hyekyoung, Tamang, Sudarsan, Ko, Jae-Hyeon, Kim, Sungwoo, Kim, Yong-Hyun, Jeong, Sohee
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 07-03-2016; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Cations; Chemical synthesis; Chlorides; co-passivation; Cobalt; Colloid chemistry; colloidal quantum dots; Colloids; Control surfaces; Covalence; Crystal structure; Density; Density functional theory; Functional anatomy; halides; Indium; indium phosphide; Indium phosphides; Ligands; Mathematical analysis; Passivity; Phosphine; Phosphorus; Quantum dots; Stabilization; tetrahedral shape; indium phosphide; co-passivation; colloidal quantum dots; tetrahedral shape; halides
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201600289

Wet chemical synthesis of covalent III‐V colloidal quantum dots (CQDs) has been challenging because of uncontrolled surfaces and a poor understanding of surface–ligand interactions. We report a simple acid‐free approach to synthesize highly crystalline indium phosphide CQDs in the unique tetrahedral shape by using tris(dimethylamino) phosphine and indium trichloride as the phosphorus and indium precursors, dissolved in oleylamine. Our chemical analyses indicate that both the oleylamine and chloride ligands participate in the stabilization of tetrahedral‐shaped InP CQDs covered with cation‐rich (111) facets. Based on density functional theory calculations, we propose that fractional dangling electrons of the In‐rich (111) surface could be completely passivated by three halide and one primary amine ligands per the (2×2) surface unit, satisfying the 8‐electron rule. This halide–amine co‐passivation strategy will benefit the synthesis of stable III‐V CQDs with controlled surfaces.
InP colloidal tetrahedral nanocrystals were synthesized through a simple acid‐free approach using tris(dimethylamino) phosphine and indium trichloride dissolved in oleylamine. Their formation was attributed to the unique stabilization of the In‐rich (111) facets by co‐passivation with halide and primary amine.