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<h2>QDs subgroup:</h2> | <h2>QDs subgroup:</h2> | ||
<h3>Synthesis of CdSe QDs </h3> | <h3>Synthesis of CdSe QDs </h3> | ||
+ | We synthesized CdSe QDs using a protocol described in.<p></p> | ||
<h4><b>1. Equipment and Materials</b></h4> | <h4><b>1. Equipment and Materials</b></h4> | ||
(1) Equipment<p></p> | (1) Equipment<p></p> | ||
− | Dual vacuum-line, 10ml flasks, 50ml flask, 500ml flasks, 25ml three-necked flask, constant temperature magnetic stirrer, heating block, aluminum foil, house vacuum, vacuum oven | + | Dual vacuum-line, 10ml flasks, 50ml flask, 500ml flasks, 25ml three-necked flask, constant temperature magnetic stirrer, heating block, aluminum foil, house vacuum, vacuum oven, droppers, stirring rod, Buchner funnel, Buchner flask, rubber tubes, syringes, pipettes, electronic balance, rubber stoppers, centrifuge, ultrasonic cleaning machine.<p></p> |
(2) Materials<p></p> | (2) Materials<p></p> | ||
− | Tetramethylammonium hydroxide(TMAH | + | Tetramethylammonium hydroxide anhydrate(TMAH), selenium powder(99.999%), Cadmium acetate dehydrate(98.5%), stearic acid(90+%), methanol, ethanol, dichloromethane, acetone, 1-octadecene(ODE, 90%), n-butylamine(98%), n-hexane, nitrogen. <p></p> |
<h4><b>2. Procedures</b></h4> | <h4><b>2. Procedures</b></h4> | ||
− | (1) Synthesis of CdSt2<p></p> | + | (1) Synthesis of CdSt2 <p></p> |
− | Tetramethylammonium hydroxide (TMAH) | + | Tetramethylammonium hydroxide(TMAH,20mmol,1.8230g), stearic acid(HSt, 20mmol, 5.6896g) and methanol(100ml) were mixed in a 500ml flask, stir for 20min to dissolve. Cadmium acetate dehydrate(CdAc2·2H2O, 10mmol, 2.6653g) was dissloved in methanol(20mL) in a 50ml flask. CdAc2 solution was then added into the HSt solution drop by drop and stirred rapidly during the addition to get the white precipitate of CdSt2. The white precipitate was filtered using a suction apparatus, washed with methanol for 3 times, and dried overnight in the vacuum oven.<p></p> |
(2) Synthesis of CdSe<p></p> | (2) Synthesis of CdSe<p></p> | ||
− | + | CdSt2(10mmol,0.0678g) and 1-octadecene(ODE, 90%, 4mL) were mixed in a 25ml three-necked flask, degassed and stirred in N2 atmosphere. Then this reaction system was heated to 250℃. Se powder(15mmol,0.0118g) was added into ODE(3mL) and was dispersed in ODE using sonication. To the system, 1ml of the Se solution was injected quickly. The reaction system was cooled to 220℃ and stabilized at this temperature for 3min to allow the growth of CdSe nanocrystals. <p></p> | |
− | (3) | + | (3)Purification and isolation of CdSe<p></p> |
− | + | The mixture of 0.05ml of n-butylamine(98%) and 2ml ethanol was added into 1ml of product solution in a 10ml flask, heated for 5 minutes at 50℃. Discarded the upper alcohol phase after the centrifugation. Excessive ethanol was added to the lower phase and then centrifugalized to get the precipitate of CdSe quantum dots. CdSe QDs are then dissolved in CH2Cl2 to preserve. <p></p> | |
<h3>Synthesis of CdS NRs </h3> | <h3>Synthesis of CdS NRs </h3> | ||
<h4><b>1. Equipment and Materials</b></h4> | <h4><b>1. Equipment and Materials</b></h4> | ||
(1) Equipment<p></p> | (1) Equipment<p></p> | ||
− | Dual vacuum-line, 50ml flasks 100ml flasks, 500ml flasks, 25ml three-necked flask, constant temperature magnetic stirrer, heating block, aluminum foil, stirrer, rubber tubes, syringes, pipettes, electronic balance, rubber stoppers, centrifuge.<p></p> | + | Dual vacuum-line, 50ml flasks,100ml flasks, 500ml flasks, 25ml three-necked flask, constant temperature magnetic stirrer, heating block, aluminum foil, stirrer, rubber tubes, syringes, pipettes, electronic balance, rubber stoppers, centrifuge. <p></p> |
(2) Materials<p></p> | (2) Materials<p></p> | ||
− | Cadmium oxide(CdO, 99.99%), octadecylphosphonic acid(ODPA,99.99%), trioctylphosphine oxide(TOPO,99%), hexylphosphonic acid(HPA, 99%), hexamethyldisilathiane((TMS)2S, synthesis grade), tributyphophine(TBP, 97%), trioctylphophine(TOP,97%), sulfur(S, 99.998%), methanol, toluene, acetone, ethanol | + | Cadmium oxide(CdO,99.99%), octadecylphosphonic acid(ODPA,99.99%), trioctylphosphine oxide(TOPO,99%), hexylphosphonic acid(HPA, 99%), hexamethyldisilathiane((TMS)2S, synthesis grade), tributyphophine(TBP, 97%), trioctylphophine(TOP,97%), sulfur(S, 99.998%), methanol, toluene, acetone, ethanol. <p></p> |
<h4><b>2. Procedures</b></h4> | <h4><b>2. Procedures</b></h4> | ||
(1) Synthesis of CdS seeds<p></p> | (1) Synthesis of CdS seeds<p></p> | ||
− | + | Cadmium oxide(CdO, 0.100g), octadecylphosphonic acid (ODPA, 0.603g) and trioctylphosphine oxide (TOPO, 3.299g) were mixed in a 25ml three-necked flask. The reaction system was degassed and then heated to 300℃ under N2 atmosphere to allow CdO to dissolve. After CdO dissolved, the solution was cooled to 120℃ and degassed for about 30 minutes. The system was then heated and stabilized at 320℃ under N2 atmosphere. Hexamethyldisilathiane (TMS)2S(0.179g) and TBP(3g) was mixed to make a sulfur stock solution and then quickly injected to the system. The nanocrystals were allowed to grow at 250℃ for 7.5min. Then the toluene was injected and the reaction system was quickly cooled to room temperature. The product was precipitated with excessive methanol and washed twice with a 1:1 mixture of toluene and methanol. The final precipitate was dissolved in 5mL of TOP.<p></p> | |
(2) Synthesis of CdS nanorods(NRs)<p></p> | (2) Synthesis of CdS nanorods(NRs)<p></p> | ||
− | + | 0.124g of sulfur in 1.5ml of TOP was prepared beforehand by heating and stirring and at 80℃ after degassing for 20min. After the sulfur dissolved and the system cooled to room temperature, the product solution in (1) with 8*10^-8mol CdS seeds was added to the solution to make a seed containing solution. CdO(0.086g), TOPO(3g), ODPA(0.290g),HPA(0.080g) was mixed in a 25ml three-necked flask, degassed at 120℃ and heated to 350℃ for 30min under N2 atmosphere. After which TOP(1.5ml) was injected in the mixture. The temperature of the solution was stabilized at 350℃ and then to the system the seed-containing solution was quickly injected. The solution was cooled after 7min to stop the growth of nanorods. The product was precipitated with a 1:1:1 mixture of acetone, toluene and methanol and washed twice with methanol. The final product was redissolved with toluene. <p></p> | |
(3) Separation of CdS NRs<p></p> | (3) Separation of CdS NRs<p></p> | ||
Get the precipitate by adding a mixture of acetone, toluene and methanol(1:1:1) and redissolved it by toluene, and then get precipitation by methanol. The precipitate was dissolved in chloroform and precipitated again by ethanol. Using toluene to dissolve the final product.<p></p> | Get the precipitate by adding a mixture of acetone, toluene and methanol(1:1:1) and redissolved it by toluene, and then get precipitation by methanol. The precipitate was dissolved in chloroform and precipitated again by ethanol. Using toluene to dissolve the final product.<p></p> | ||
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Revision as of 18:01, 18 October 2016