Process for forming shaped group II-VI semiconductor nanocrystals, and product formed using process

A process for forming shaped Group II-VI semiconductor nanocrystals in a heated binary mixture of surfactants which comprises:

• a) forming one or more solutions, each comprising one or more Group II and/or Group VI semiconductor nanocrystal precursors dissolved in a liquid which is a solvent for said one or more semiconductor precursors;
• b) forming a binary mixture of high boiling organic surfactants comprising:
• i) a first surfactant;
• and
• ii) a second surfactant;
• c) adjusting the ratio of said first and second surfactants in said binary mixture to control the shape of said semiconductor nanocrystals to be formed therein;
• d) heating said binary mixture of surfactants to a temperature at which said Group II and Group VI precursors will react in said heated binary mixture of surfactants to form said Group II-VI semiconductor nanocrystals;
• e) adding said one or more solutions of Group II and Group VI semiconductor nanocrystal precursors to said heated binary mixture of surfactants to form said semiconductor nanocrystals;
• and
• f) subsequently reducing the temperature of said heated binary mixture of surfactants containing said semiconductor nanocrystals to stop said growth of said semiconductor nanocrystals.

A process for forming shaped Group II-VI semiconductor nanocrystals in a heated binary mixture of surfactants which comprises:

• a) forming a solution comprising:
• i) a first semiconductor precursor comprising one or more particular Group II metals, or compounds containing one or more particular Group II metals;
• ii) a second semiconductor precursor comprising one or more particular Group VI elements, or compounds containing one or more particular Group VI elements;
• and
• iii) a liquid which is a solvent for said first and second precursors;
• b) forming a binary mixture of high boiling phosphorus-containing organic surfactants comprising:
• i) a first surfactant capable of promoting growth of spherical semiconductor nanocrystals when a sufficient amount of said surfactant is present in said binary mixture of surfactants;
• and
• ii) a second surfactant capable of promoting growth of rod-like shaped semiconductor nanocrystals when a sufficient amount of said surfactant is present in said binary mixture of surfactants;
• c) adjusting the ratio of said first and second surfactants in said binary mixture to control the shape of said semiconductor nanocrystals to be formed therein;
• d) heating said binary mixture of phosphorus-containing organic surfactants to a temperature sufficient to permit formation of Group II-VI semiconductor nanocrystals therein;
• e) adding said solution of Group II and Group VI semiconductor nanocrystal precursors to said heated binary mixture of surfactants to form said semiconductor nanocrystals;
• and
• f) subsequently reducing the temperature of said heated binary mixture of surfactants containing said semiconductor nanocrystals to stop said growth of said semiconductor nanocrystals.

A process for forming shaped CdSe semiconductor nanocrystals in a heated binary mixture of surfactants which comprises:

• a) forming a solution comprising:
• i) a first semiconductor precursor comprising Cd metal, and/or one or more compounds containing Cd metal;
• ii) a second semiconductor precursor comprising Se, and/or one or more compounds containing Se;
• and
• iii) a liquid which is a solvent for said first and second precursors;
• b) forming a binary mixture of high boiling phosphorus-containing organic surfactants comprising:
• i) a first phosphorus-containing surfactant capable of promoting growth of spherical semiconductor nanocrystals with increased percentage of said first surfactant in the ratio of said surfactants in said binary mixture of surfactants;
• and
• ii) a second surfactant capable of promoting growth of rod-like shaped semiconductor nanocrystals with increased percentage of said second surfactant in the ratio of said surfactants in said binary mixture of surfactants;
• c) adjusting the ratio of said first and second surfactants in said binary mixture to control the shape of said CdSe semiconductor nanocrystals to be formed therein;
• d) heating said binary mixture of phosphorus-containing organic surfactants to a temperature sufficient to permit formation of Group II-VI semiconductor nanocrystals therein;
• e) adding said solution of Cd and Se semiconductor nanocrystal precursors to said heated binary mixture of surfactants to form said CdSe semiconductor nanocrystals;
• and
• f) subsequently reducing the temperature of said heated binary mixture of surfactants containing said semiconductor nanocrystals to stop said growth of said semiconductor nanocrystals.