Tri octylphosphine

Bismuth nanocrystals were synthesized according to Son, et al^{12 (link)}. Briefly, 3.6 grams (5 mmol) of bismuth neodecanoate (Sigma-Aldrich St. Louis, MO, USA) was combined with 25 mL of 1-octadecene (Sigma-Aldrich St. Louis, MO, USA). The mixture was then heated to 120 °C under a N₂ atmosphere for 2 hours to remove water and dissolved oxygen. The mixture was then cooled to 80 °C with continuous stirring. 1.2 mL of 1-dodecanethiol (DDT) (Sigma-Aldrich St. Louis, MO, USA) was then added and the mixture was kept at 80 °C for 5 minutes. The addition of DDT caused the solution to change from colorless to yellow, indicating the formation of the bismuth dodecanethiolate complex. Next, 5 mL of tri-octylphosphine (Alfa Aesar, Heysham, England) was injected, causing the yellow solution to turn black. The reaction was then cooled and maintained at its growing temperature of 60 °C for 30 minutes with continuous stirring. The nanocrystals formed were then precipitated with a 10:1 (v/v) mixture of acetone/tetrahydrofuran (THF), and retrieved by centrifugation (17,000 g × 10 minutes) and washed several times with 10:1 (v/v) acetone/THF.