Synthesis and Nanostructures of Metal Selenide Precursors for Cu(In,Ga)Se₂ Thin‐Film Solar Cells

Abstract

A nanoink solution-based process was developed as a low-costing method for the fabrication of Cu(In,Ga)Se2 (CIGSe) thin-film photovoltaic cells. The sonochemical synthesis of CIGSe nanocrystals of the nanoink through step-by-step mixing of the reactants was investigated. To achieve the ideal stoichiometry of Cu(In0.7 Ga0.3 )Se2 to tune the bandgap and to fabricate high-efficiency photovoltaic cells, the synthetic parameters, the concentration of hydrazine, and the amount used of the gallium precursor were investigated. As the hydrazine concentration increased, gallium loss was observed in the CIGSe product. The gallium content in the reactant mixture strongly affected the metal stoichiometry of the prepared CIGSe nanocrystals. The nanoink solution based fabrication of thin-film photovoltaic cells was also explored, and the resulting device showed a conversion efficiency of 5.17 %.

Carbon Impurity Minimization of Solution-Processed, Thin-Film Photovoltaics via Ligand Engineering of CuInS2 Nanoparticles

“…The resulting film morphologies are thick, homogeneous, and coarse-graineda trait believed to be crucial in reaching the high efficiencies that these devices achieve. In order to reduce the carbon content in solution-processed, thin-film devices, several techniques have been studied, including ligand-exchange strategies, , direct-synthesis procedures utilizing inorganic or smaller-chain ligands, ,, or via the sonochemical approach in which typical surfactants are also omitted. − Many of these alternate strategies, however, utilize methods that significantly increase fabrication complexity and material usage, especially for the ligand-exchange methods or involve procedures that may have increased difficulties in scale-up due to less commonly used materials. While the sonochemical approach is attractive in that it can produce surfactant-free Cu­(In 1– x Ga x )­(S 1– y Se y ) 2 NPs under bulk, low-temperature conditions, some of these methods still require the use of toxic hydrazine or show limited device performance (<1% PCE), with all methods appearing to suffer from a high degree of particle agglomeration, which may lead to difficulties when coating films.…”

CuInTe2 Nanocrystals: Shape and Size Control, Formation Mechanism and Application, and Use as Photovoltaics

“…I–III–VI 2 semiconductors have proved to be one of the highest power conversion efficiency photovoltaic materials in thin film photovoltaic applications [1,2,3,4]. In particular, cells with efficiency exceeding 20% has been produced using the Cu(In,Ga)Se 2 as a solar absorber layer [5].…”

Synthesis of CuInS2 by Sulfide Ion‐Exchange of CuIn(OH)5 Precursors

“…4 The CuInS 2 semiconductor has been synthesized by a colloidal solution-process, but reaction conditions are hypersensitive, yielding a small quantity. [5][6][7] This method has some disadvantages, including high-temperature processing, long-reaction time, and surface modification to remove organics. 7,8 Herein, we report a facile synthetic route to obtain CuInS 2 semiconductor by Na 2 S anion-exchange with bimetallic hydroxide precursor in aqueous solution at room temperature.…”

“…The I–III–VI 2 chalcopyrite semiconductor is a promising candidate in thin film solar cells because of its low cost and high efficiency . The CuInS 2 semiconductor has been synthesized by a colloidal solution‐process, but reaction conditions are hypersensitive, yielding a small quantity . This method has some disadvantages, including high‐temperature processing, long‐reaction time, and surface modification to remove organics …”