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In this study, as a novel approach to thin-film solar cells based on tin sulfide, an environmentally friendly material, we attempted to fabricate (Ge, Sn)S thin films for application in multi-junction solar cells. A (Ge0.42 Sn0.58)S thin film was prepared via co-evaporation. The (Ge0.42 Sn0.58)S thin film formed a (Ge, Sn)S solid solution, as confirmed by X-ray diffraction (XRD) and Raman spectroscopy analyses. The open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and power conversion efficiency (PCE) of (Ge0.42 Sn0.58)S thin-film solar cells were 0.29 V, 6.92 mA/cm2, 0.34, and 0.67%, respectively; moreover, the device showed a band gap of 1.42–1.52 eV. We showed that solar cells can be realized even in a composition range with a relatively higher Ge concentration than the (Ge, Sn)S solar cells reported to date. This result enhances the feasibility of multi-junction SnS-system thin-film solar cells. [ABSTRACT FROM AUTHOR]

Cu2SnS3 (CTS) is a promising compound for use as an absorber layer in thin-film solar cells because it is made up of low-cost and abundant elements. However, the band gap energy of 0.94 eV for monoclinic Cu2SnS3 is less than the optimal value for absorber layers in single-junction solar cells. On the other hand, the band gap energy of Cu2GeS3 (CGS) is approximately 1.5-1.6 eV. Therefore, in this study, we carried out the synthesis of Cu2Sn1− xGe xS3, which is a solid solution of Cu2SnS3 and Cu2GeS3. The structure of the prepared samples was investigated using X-ray diffraction and Raman analyses. Diffuse reflectance spectra were obtained using a UV-Vis-NIR spectrometer and used to estimate the band gap energy. In X-ray diffraction patterns from the synthesized compounds, the diffraction peaks were found to shift to higher 2 θ values with increasing x, indicating a decrease in the lattice constants. In addition, the estimated band gap energy increased from 0.86 to 1.53 eV with increasing x. Cu2Sn1 − xGe xS3 is, therefore, a potential candidate for use as the absorber layer in thin film solar cells because its band gap energy can be adjusted simply by varying its composition. [ABSTRACT FROM AUTHOR]

Cu2SnS3 (CTS) is a promising compound for use as an absorber layer in thin-film solar cells because it is made up of low-cost and abundant elements. However, the band gap energy of 0.94 eV for monoclinic Cu2SnS3 is less than the optimal value for absorber layers in single-junction solar cells. On the other hand, the band gap energy of Cu2GeS3 (CGS) is approximately 1.5-1.6 eV. Therefore, in this study, we carried out the synthesis of Cu2Sn1− xGe xS3, which is a solid solution of Cu2SnS3 and Cu2GeS3. The structure of the prepared samples was investigated using X-ray diffraction and Raman analyses. Diffuse reflectance spectra were obtained using a UV-Vis-NIR spectrometer and used to estimate the band gap energy. In X-ray diffraction patterns from the synthesized compounds, the diffraction peaks were found to shift to higher 2 θ values with increasing x, indicating a decrease in the lattice constants. In addition, the estimated band gap energy increased from 0.86 to 1.53 eV with increasing x. Cu2Sn1 − xGe xS3 is, therefore, a potential candidate for use as the absorber layer in thin film solar cells because its band gap energy can be adjusted simply by varying its composition. [ABSTRACT FROM AUTHOR]

Cu2SnS3 is a promising compound for use as an absorber layer in thin film solar cells because it is made up of low-cost and abundant elements, and has a high optical absorption coefficient. However, the band gap energy of monoclinic Cu2SnS3 is less than the value required for absorber layers in single-junction solar cells. On the other hand, the band gap energy of Cu2SiS3 was reported to be approximately 2.5 eV, which is sufficiently large for this purpose. Therefore, in the present study, an attempt was made to synthesize Cu2Si x Sn1- xS3, which is a solid solution between Cu2SnS3 and Cu2SiS3. In X-ray diffraction patterns from the synthesized compounds, the diffraction peaks were found to shift to higher 2 θ values with increasing x, indicating a decrease in the lattice constants. In addition, the estimated band gap energy increased from 0.85 to 2.56 eV with increasing x. Cu2Si x Sn1- xS3 is therefore a potential candidate for use as the absorber layer in thin film solar cells because its band gap energy can be adjusted simply by varying its composition. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Cu2SnS3 is a promising compound for use as an absorber layer in thin film solar cells because it is made up of low-cost and abundant elements, and has a high optical absorption coefficient. However, the band gap energy of monoclinic Cu2SnS3 is less than the value required for absorber layers in single-junction solar cells. On the other hand, the band gap energy of Cu2SiS3 was reported to be approximately 2.5 eV, which is sufficiently large for this purpose. Therefore, in the present study, an attempt was made to synthesize Cu2Si x Sn1- xS3, which is a solid solution between Cu2SnS3 and Cu2SiS3. In X-ray diffraction patterns from the synthesized compounds, the diffraction peaks were found to shift to higher 2 θ values with increasing x, indicating a decrease in the lattice constants. In addition, the estimated band gap energy increased from 0.85 to 2.56 eV with increasing x. Cu2Si x Sn1- xS3 is therefore a potential candidate for use as the absorber layer in thin film solar cells because its band gap energy can be adjusted simply by varying its composition. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

To enlarge the bandgap of Cu2SnS3 (CTS), Ag‐incorporating CTS thin films are successfully deposited by sulfurizing Ag‐Cu‐Sn precursors featuring various Ag contents and the constant Cu/Sn ratio of 1.75, which is the optimal value for CTS thin‐film solar cells. To control the Ag content of the films, the thickness of the Ag layers of the precursors is varied from 0 to 200 nm, which corresponds to the Ag/(Ag + Cu) ratio of the films varying from 0 to 0.32. The films featuring Ag/(Ag + Cu) ratios smaller than 0.16 are solid solutions of CTS and Ag2SnS3, that is, (Cu,Ag)2SnS3 (CATS), while the film featuring the Ag/(Ag + Cu) ratio of 0.32 appears to be a mixture of CATS and Ag‐Sn‐S related crystals, such as Ag8SnS6. The grain size and bandgap increase as the Ag/(Ag + Cu) ratio increases up to 0.16. The highest power conversion efficiency (PCE) of 3.6% is obtained for the cell featuring the Ag/(Ag + Cu) ratio of 0.08. The highest open cell voltage (VOC) for the CATS thin‐film solar cells is obtained to be 0.284 mV. However, the improvement in PCE is attributed to the increase in the short‐circuit current density and fill factor of the cell rather than the increase in VOC. [ABSTRACT FROM AUTHOR]