Singlet-Oxygen Sensitization by Associates of Methylene Blue with Colloidal Ag2S Quantum Dots Passivated by Thioglycolic Acid

Photostimulated control of luminescence quantum yield for colloidal Ag2S/2-MPA quantum dots

“…The molar ratio [AgNO 3 ] : [2-MPA] was 1 : 2. In the synthesis, 2.4 mmol (408 mg) of AgNO 3 was dissolved in 30 ml of ethylene glycol under constant stirring with a magnetic stirrer at 200 rpm in a thermostatic glass ask at a temperature of 25 C. According to works, [24][25][26][27][31][32][33] the synthesis of Ag 2 S QDs passivated with mercaptopropionic acid can be carried out at temperatures of 20-145 C. The use of a low temperature (20-25 C) leads to a decrease in the growth rate of colloidal QDs, which, as a rule, makes it possible to obtain Ag 2 S QDs with small size ($1.5-2.0 nm). 27 Aer that, 4.8 mmol (513.6 mg) of 2-MPA was dissolved in ethylene glycol and added to the ask with the solution.…”

“…10,11,23,26,31 In the case of using molecules of thioglycolic acid (TGA) as the passivating agent, a strong dependence of the QD optical properties on the sulfur concentration and the silver-sulfur ratio is observed. 10,11,[31][32][33] In the works, 10,11,31 it was assumed that the centers of radiative recombination of Ag 2 S QDs are of an interfacial nature. The low quantum yield of the QDs is explained, as a rule, by numerous surface defects formed during rapid intense release of sulfur atoms involved in the QD growth.…”

Room Temperature Silicon Detector for IR Range Coated with Ag2S Quantum Dots

“…Interest in using QDs is also due to the ease of the adjustment of the optical properties of the QD by changing its size . Ag 2 S has a relatively narrow bandgap of 1.0 eV in bulk and a high concentration of trap states, and the presence of which is associated with QD nonstoichiometry . The aqueous solutions of AgNO 3 and Na 2 S were used as the initial reagents.…”

“…The aqueous solutions of AgNO 3 and Na 2 S were used as the initial reagents. Aqueous synthesis of colloidal Ag 2 S QDs was carried out under conditions similar to those described in previous studies . To remove the reaction by‐products, acetone was used in aqueous colloidal Ag 2 S QDs solution, followed by centrifuging the solution.…”