Solvothermal Preparation, Processing, and Characterization of Nanocrystalline CuIn_1-xAl_xSe₂ Materials

Abstract

We report solvothermal preparations of nanocrystalline CuIn 1-x Al x Se 2 materials prepared from the reaction of Se, CuX 2 (X = Clor stearate), InCl 3 , and Al(oleate) 3 in refluxing oleylamine for 30 minutes to 3 hours. Scanning electron microscopy (SEM) images reveal morphologies consisting of hexagonal plates (100-400 nm diameter) with smaller isomorphic nodules. Micro-Raman spectroscopy, x-ray diffraction, and optical bandgap data are consistent with Al 3+ incorporation into the chalcopyrite structure. For aluminum-containing reactions, product Al/(In+Al) ratios are estimated to be between 0.15 and 0.35 regardless of the indiumaluminum stoichiometry employed in the reaction. When Se is added to the reaction last, the reaction pathway involves an early-formed Cu 2-x Se(s) intermediate that appears to react with Inand Al-containing species simultaneously. This intermediate is avoided when heating InCl 3 , Al(oleate) 3 , and Se together prior to Cu addition, but the final product includes Se contamination that must be removed or reacted by annealing.

Syntheses and Characterizations of CuIn1-xZnxSe2 Chalcopyrite Nanoparticles

“…Therefore, the band gap of these compounds increases [31]. All these results show that the role of zinc is identical to that of aluminum in Cu (In, Al) Se 2 powders [32,33] as well as gallium in Cu (In, Ga) Se 2 powders [11,31,34,35]. In the latter case, Zn is cheaper than Ga concerning the ease of acquisition because it is a natural component of the Earth's crust and is an integral part of our environment, while Ga is a rare chemical element.…”

“…Therefore, the band gap of these compounds increases [31]. All these results show that the role of zinc is identical to that of aluminum in Cu (In, Al) Se2 powders [32,33] as Absorbance measurements on CuIn 1-x Zn x Se 2 powders using UV-vis spectroscopy in the wavelength range from 200 to 1100 nm at room temperature were performed to deter-mine the optical parameters of CuIn 1-x Zn x Se 2 . The sample was dispersed in absolute ethanol (≥99.9%) under intense sonication for 20 min and ethanol was used as a reference.…”

Cyclic Voltammetric Study and Nucleation of Electrodeposited Cu(In,Al)Se2Thin Films with Sodium Dodecyl Sulfate Additive

“…11. The peak at 173 cm −1 is corresponded to the A1 mode for pure CIS film that fabricated at −0.7 V. 30,31 The other peaks between 176 cm −1 and 179 cm −1 are assigned to the A1 mode for CIAS films which are similar to CIGS films, [32][33][34] and the A1 frequency reveals a shift as increasing the Al/(In+Al) ratio. These values are higher than those peaks for pure CIS films (173∼176 cm −1 ) since Al is present.…”