Investigation of Cu₂ZnSnS₄ Formation from Metal Salts and Thioacetamide

Abstract

Copper zinc tin sulfide (Cu2ZnSnS4, CZTS) is a very promising alternative to semiconductors based on Ga or In as solar absorber material. CZTS consists of abundant and cheap elements and in addition it displays very beneficial properties like a high optical absorption coefficient and an ideal band gap for photovoltaic applications. In this contribution, we present the preparation of thin films of copper zinc tin sulfide from metal salts (copper(I) iodide, zinc(II) acetate, and tin(II) chloride) and thioacetamide as sulfur source by a solution-based precursor method. The influence of synthesizing temperatures and concentration of thioacetamide in the precursor solution on the obtained CZTS materials was investigated. X-ray diffraction studies show that kesterite CZTS is formed. Depending on the temperature, nanocrystalline films with primary crystallite sizes from 8 nm (180 °C) up to approximately 150 nm (450 °C) were obtained. The early stages of the CZTS formation were monitored by time-resolved simultaneous grazing incident small- and wide-angle X-ray scattering (GISAXS, GIWAXS) analysis directly in thin layers revealing that the thermally induced reaction already starts at approximately 105 °C. The thin films exhibit high optical absorption (>1 × 104 cm−1) and an optical band gap between 1.41 and 1.81 eV depending on the heat treatment. The obtained CZTS materials are of copper-poor and zinc-rich nature, which is ideal for the use in photovoltaic applications.

Cadmium effect on optical properties of Cu2Zn1−xCdxSnS4 quinternary alloys nanostructures

“…3. The nanostructures were copper-poor and zinc-rich at all x contents except for x = 1 (Suehiro et al, 2014;Fischereder et al, 2010;Jiang et al, 2011). This indicates a higher p-type conductivity, which can be useful for PV applications (Chen et al, 2010).…”

Synthesis of wurtzite Cu2ZnSnS4 thin films directly on glass substrates by the solvothermal method

“…So it is believed that the power conversion efficiency of CZTS can be further improved. CZTS thin films have been synthesized by various methods such as vacuum methods (sputtering, thermal evaporation, spraypyrolysis) [4][5][6][7][8][9], non-vacuum methods (electrodeposition, sol-gel, chemical bath deposition, successive ionic layer absorption and reaction, solvothermal synthesis) [10][11][12][13][14][15][16][17]. Compared with the vacuum methods, the non-vacuum methods can attract a great deal of attention owing to their simpleness, low-price and no need of sophisticated instrumention.…”

Spin-coated kesterite CZTS thin films for photovoltaic applications

“…Alternative processing strategies based on electrochemical and chemical solution deposition in the atmosphere have, therefore, been proposed, but these have the disadvantage of requiring high processing temperatures or harsh chemicals [7,8]. Stoichiometric CZTS thin films have also been produced through layer-by-layer techniques [9], sol-gel sulfurizing methods [10], or spin/spray-coating [11][12][13][14][15][16] under nonvacuum conditions.…”