title: Size-confined fixed-composition and composition-dependent engineered band gap alloying induces different internal structures in L-cysteine-capped alloyed quaternary CdZnTeS quantum dots.
abstract: The development of alloyed quantum dot (QD) nanocrystals with attractive optical properties for a wide array of chemical and biological applications is a growing research field. In this work, size-tunable engineered band gap composition-dependent alloying and fixed-composition alloying were employed to fabricate new L-cysteine-capped alloyed quaternary CdZnTeS QDs exhibiting different internal structures. Lattice parameters simulated based on powder X-ray diffraction (PXRD) revealed the internal structure of the composition-dependent alloyed CdxZnyTeS QDs to have a gradient nature, whereas the fixed-composition alloyed QDs exhibited a homogenous internal structure. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis confirmed the size-confined nature and monodispersity of the alloyed nanocrystals. The zeta potential values were within the accepted range of colloidal stability. Circular dichroism (CD) analysis showed that the surface-capped L-cysteine ligand induced electronic and conformational chiroptical changes in the alloyed nanocrystals. The photoluminescence (PL) quantum yield (QY) values of the gradient alloyed QDs were 27-61%, whereas for the homogenous alloyed QDs, the PL QY values were spectacularly high (72-93%). Our work demonstrates that engineered fixed alloying produces homogenous QD nanocrystals with higher PL QY than composition-dependent alloying.
authors.affiliation: Laboratory of Biotechnology, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.
authors.forename: Oluwasesan
authors.initials: O
authors.lastname: Adegoke
authors.affiliation: Laboratory of Biotechnology, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.|Laboratory of Biotechnology, Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.
authors.forename: Enoch Y
authors.initials: EY
authors.lastname: Park
mesh_terms: D000497:Alloys / Q000737:chemistry; D002104:Cadmium / Q000737:chemistry*; D002942:Circular Dichroism; D003545:Cysteine / Q000737:chemistry*; D000067493:Dynamic Light Scattering; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D045663:Quantum Dots / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D000497:Alloys; C474490:CdZnTe; D002104:Cadmium; D015032:Zinc; D003545:Cysteine; D013691:Tellurium