Quantum dot, light emitting material and manufacturing method of quantum dot comprising thermal treatment of solution containing formed quantum dot

A manufacturing method of a quantum dot, comprising:

• providing a first solution comprising a group 12 element, a group 13 element, or a group 14 element;
• providing a second solution comprising a group 15 element or a group 16 element;
• mixing the first solution with the second solution to form a third solution;
• adding a material comprising the group 12 element, the group 13 element, or the group 14 element and a fourth solution comprising the group 15 element or the group 16 element to the third solution to form a fifth solution comprising the quantum dot;
• and
• performing a thermal treatment to the fifth solution, wherein a temperature of the thermal treatment is higher than a temperature of forming the fifth solution comprising the quantum dot by 15° C. to 75° C., and a time period of the thermal treatment is 3 minutes to 7 minutes;
• a ratio of an emission intensity to an absorption intensity of the quantum dot at a characteristic wavelength ranges from 1.5×108 CPS/Abs. to 2.0×109 CPS/Abs. after the thermal treatment, and the characteristic wavelength is a shorter wavelength of two wavelengths corresponding to half of a maximum intensity of an emission peak of the quantum dot after the thermal treatment.