The effect of tartaric acid in the deposition of Sb2S3 films by chemical spray pyrolysis

A green and facile hydrothermal approach for the synthesis of high-quality semi-conducting Sb2S3 thin films

“…The Eg of the Sb2S3 film obtained in this work were further compared with that of the Sb2S3 films prepared by other reported methods and the results were summarized in Table 2. The data revealed that the obtained Sb2S3 film annealed at 450 ºC demonstrated a narrow Eg of 1.63 eV, which was remarkably lower than that of the Sb2S3 films prepared by other conventional methods, including chemical spray pyrolysis (Eg of 1.80 ~ 2.10 eV) [7,31,32], chemical bath deposition (Eg of 1.70 ~ 2.24 eV) [9,11,17,33], vacuum thermal evaporation (Eg of 1.78 ~ 1.98 eV) [8,34], and electrodeposition (Eg of 1.86 eV) [10]. These results suggested that the hydrothermal approach in this work was efficient to synthesize high-quality Sb2S3 films as the absorber layer material for high-performance solar cells.…”

Sb2S3 grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

“…An absorber bandgap of 1.65 eV is found in solar cells with Sb 2 S 3 prepared by ALD [5,19] or in solar cells with Sb 2 S 3 prepared by CBD, as estimated from the photocurrent edge at around 750 nm in the published EQE plots [2,4,6–9 11–12 15–17 40–41 50–53]. Any E g larger than 1.7 eV up to 2.6 eV have been attributed to nanocrystalline Sb 2 S 3 [1,44,54], or to amorphous Sb 2 S 3 [6,44–45 53], while it is also known that contamination, most notably with oxygen, can significantly increase the bandgap value of metal sulfide films [23,55–56]. Values of 1.52–1.55 eV are reported for layers of nanotubes, -rods, or -flakes that consist of single phase Sb 2 S 3 [57–59].…”

“…To generalize, not only chlorides but also the SbI 3 complex with tu, Sb(tu) 3 I 3 , decompose at around 200 °C [72]. Also, our preparatory study on the use of SbCl 3 and tu for growing Sb 2 S 3 films by spray pyrolysis [23] indicated the use of 250 °C as a suitable growth temperature according to thermal analysis of the Sb(tu) 2 Cl 3 with tartaric acid as the complexing agent. Besides the requirement stemming from the use of the precursor, temperatures of above 225 °C are required for the crystallization of Sb 2 S 3 [44].…”

“…The precursors for Sb and S have been SbCl 3 and thiourea (tu) [21] or thioacetamide [22], respectively, dissolved in water together with a complexing agent such as tartaric acid to reduce the hydrolysis of the SbCl 3 in the spray solution [21–22]. We have observed that the use of tartaric acid as the complexing agent results in unwanted residues in the films grown by pneumatic spray [23]. Alternatively, non-aqueous solvents such as acetic acid or alcohols have been utilized to eliminate problems associated with the hydrolysis of SbCl 3 [22,24].…”

“…In general, the aqueous solvent tends to result in amorphous Sb 2 S 3 films whereas films prepared from non-aqueous solvents have been reported as polycrystalline [22,24]. So far, we have shown that for growing Sb 2 S 3 by pneumatic CSP the use of SbCl 3 and thiourea (tu) precursors with an SbCl 3 /tu molar ratio of 1:3 dissolved in methanol and sprayed on substrate at a temperature of 255 °C leads to films that consist of orthorhombic stibnite and a secondary phase that was identified as Sb 2 O 3 [23]. To suppress the formation of oxides, an excess of sulfur source in the precursor solution may be required as indicated by similar studies for indium sulfide [25–26], zinc sulfide [27] and tin sulfide [28–29] grown by pneumatic CSP.…”