(CuCl, 99.999%), trioctylphosphine oxide (TOPO, 99%), trioctylphosphine
(TOP, 97%), and selenium powder (Se, 99.99%) were purchased from Strem
Chemicals. Cadmium chloride (CdCl2, 99.99%), iodine (I2, 99.99%), iron(III) chloride (FeCl3, 98%), oleylamine
(70%), tetrakis(acetonitrile)copper(I) hexafluorophosphate, and sulfur
powder (S, 99.9%) were purchased from Sigma-Aldrich. Copper(II) chloride
(CuCl2, 99%) was purchased from Alfa Aesar. Octadecylphosphonic
acid (ODPA) and hexylphosphonic acid (HPA) were purchased from Polycarbon
Industries. Cerium(IV) ammonium nitrate (>98.5%), nitric acid (HNO3, 67−69%), anhydrous toluene and methanol were purchased
from Carlo Erba reagents.