Tolerance of Intrinsic Defects in PbS Quantum Dots

Colloidal quantum dots exhibit various defects and deviations from ideal structures due to kinetic processes, although their band gap frequently remains open and clean. In this Letter, we computationally investigate intrinsic defects in a real-size PbS quantum dot passivated with realistic Cl-ligands. We show that the colloidal intrinsic defects are ionic in nature. Unlike previous computational results, we find that even nonideal, atomically nonstoichiometric quantum dots have a clean band gap without in-gap-states provided that quantum dots satisfy electronic stoichiometry

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer

From Single Atoms to Nanocrystals: Photoreduction of [PtCl₆]^2– in Aqueous and Tetrahydrofuran Solutions of PVP

Structured platinum nanoclusters Pt_<i>n</i> (<i>n</i> = 5–30) capped by poly­(<i>N</i>-vinylpyrrolidone) (PVP) have unique and highly attractive properties as potential selective catalysts. We show that the assembly of Pt mononuclear compounds in aqueous and tetrahydrofuran (THF) solutions under UV irradiation proceed via several steps: formation of linear Pt_<i>n</i> clusters (<i>n</i> = 2–8), coalescence into mesocrystals, and transformation into Pt nanocrystals. The “quantum” size range of Pt_<i>n</i> (<i>n</i> = 5–100) clusters is intermediate between those clusters with molecular properties and those with metallic properties. The PVP “cage” acts as a nano reactor and can hinder diffusion of photoexcited Pt atoms. The diffusion of the Pt from the polymer cage is strongly affected by the hydrophobic or hydrophilic property of the solution. An aqueous solution of [PtCl₆]^2– + PVP transforms into noncrystalline aggregates of molecules of less than 1.5–2 nm in diameter, whereas in THF solution Pt nanocrystals increase proportional to the UV irradiation time up to 10 nm in diameter. Dynamic imaging by high-resolution transmission electron microscopy and low-frequency UV Raman spectra show the initial stages of Pt atoms assembled into Pt_<i>n</i> clusters. The assignment of the Raman bands is supported by density functional theory calculations. The proposed scheme of photoinduced reactions suggests the coupling of coordinatively unsaturated Pt ions inside the amidate-rich polymeric stabilizer