A simple solution-phase approach to synthesize high quality ternary AgInSe2 and band gap tunable quaternary AgIn(S1−xSex)2 nanocrystals

Abstract

A facile solution-phase route for the preparation of AgInSe₂ nanocrystals was developed by using silver nitrate, indium stearate, and oleylamine–selenium (OAm–Se) as precursors. The evolution process of the AgInSe₂ nanocrystals is discussed in detail and different reaction conditions all have a great impact on the growth and morphology of the nanocrystals. Alloyed AgIn(S_1−xSe_x)₂ nanocrystals with controlled composition across the entire range (0 ≤ x ≤ 1) was also successfully prepared by modulating the S/Se reactant mole ratio. X-ray diffraction (XRD), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were used to confirm that the alloyed AgIn(S_1−xSe_x)₂ nanocrystals are homogeneous. The UV-vis absorption spectra revealed that the band gap energies of the alloyed AgIn(S_1−xSe_x)₂ nanocrystals could be continuously tuned by increasing the Se content.