Formation Mechanisms of Cu(In_0.7Ga_0.3)Se₂ Nanocrystallites Synthesized Using Hot‐Injection and Heating‐Up Processes

Abstract

Nearly monodispersed CuIn 0.7 Ga 0.3 Se 2 (CIGS) nanocrystals were successfully prepared using the thermal decomposition of copper, indium (In), gallium (Ga), and selenium-oleylamine (OLA) complexes via the heating-up process. The phase formation sequence was CuSe-CuInSe 2 -CIGS. The CIGS nanocrystals synthesized using the heating-up process exhibited a single chalcopyrite phase and its chemical composition was close to stoichiometric. However, phase separation of the In-rich and Ga-rich phases was found using the hot-injection method due to the difference in reactivity between In-OLA and Ga-OLA complexes.

Crystallite formation mechanism of CuIn(Se,S)2 synthesized using solvothermal method

“…[11] So far the thermal decomposition method (rapid hot-injection and heating-up methods) has been the most successful and widely used in CIS and CISS nanocrystal synthesis. [12][13][14] However, this synthesis is difficult to scale up because the reagents used are toxic and expensive and the processing process is complicated. CISS and CIS nanocrystals have also been reported successfully synthesized using hydrothermal [15,16] and solvothermal [17][18][19][20] methods.…”

Two-step sintering of nanocrystalline Cu(In0.7Ga0.3)Se2

“…A detailed description of the heating-up process was reported in our previous study [16]. Twenty-five ml of oleylamine ( 4 70%, Fluka) and selenium powder (99.99%, Sigma-Aldrich) were added to a three neck flask.…”

Síntesis de kesterita Cu₂ZnSn(S,Se)₄ mediante métodos de hot-injection y solvotermal

“…[9,23] En el presente trabajo, se proponen vías de preparación alternativos a los previamente mencionados, como son "hot-injection" [24,25] y la síntesis solvotermal [7,26]. El hot-injection se ha seleccionado basándose en resultados previos logrados con estructuras de calcopirita [27], mientras que solvotermal goza de la ventaja de un pre-tratamiento previo a la calcinación bajo presión superior a la atmosférica, donde la disolución precursora se calienta por encima de su punto de ebullición, consiguiendo así mejor homogenización de los reactivos y a consecuencia una disminución de la temperatura de síntesis. Además, ambos métodos permiten un control morfológico más estricto y unas reacciones químicas más eficientes.…”