Figure 4 Optical absorption spectra of Sb 2 S 3 -TiO 2 nanostructure samples. Before (green spectrum) and after being annealed at 100°C (red spectrum), 200°C (blue-green spectrum), 300°C (black spectrum), and 400°C (brown spectrum). Photovoltaic performance of the solar cell based on Sb2S3-TiO2 nanostructure The photocurrent-voltage (I-V) performances of the solar

cells assembled using Sb2S3-TiO2 nanostructures annealed under different temperatures are shown in Figure 5. The I-V curves of the samples were measured under one sun illumination (AM1.5, 100 mW/cm2). Compared with the solar cell based on as-grown Sb2S3-TiO2 nanostructure, the solar cell performances correspondingly improved as the annealing temperatures increased from 100°C to 300°C. The open-circuit voltage (V oc) improved from 0.3 up to 0.39 V, and the short-circuit current RAD001 density (J sc) improved from 6.2 up to 12.1 mA/cm2. A power conversion efficiency of 1.47% for the sample with annealing treatment was obtained, indicating an increase of 219% (as compared to the 0.46% for the as-grown sample) as a consequence of the annealing treatment. The photovoltaic performance of annealed Sb2S3-TiO2 nanostructured solar cell under 400°C deteriorated, which coincides with the absorption spectrum. Detailed parameters of the

solar cells extracted from the I-V characteristics are listed in Table 1. Figure 5 I – V curves for the solar cells assembled using Sb 2 S selleckchem 3 -TiO 2 nanostructures annealed under varied temperature. Table 1 Parameters of Sb 2 S 3 -TiO 2 nanostructured solar cells annealed at different temperatures   V oc(V) J sc(mA/cm2) FF (%) η (%) As-synthesized Sb2S3-TiO2

0.30 6.10 0.25 0.46 Sb2S3-TiO2 under 100°C 0.33 8.65 0.28 0.79 Sb2S3-TiO2 under 200°C 0.34 10.32 0.31 1.10 Sb2S3-TiO2 under 300°C 0.39 12.15 0.31 1.47 Sb2S3-TiO2 under 400°C 0.29 3.82 0.32 0.36 V oc, open-circuit voltage; J sc, integral photocurrent density; FF, fill factor; η, power conversion efficiency. This significant improvement of the photovoltaic performance Tenofovir concentration obtained for annealed Sb2S3-TiO2 nanostructured solar cells is explained by the following reasons: (1) An enhanced absorption of sunlight caused by the red shift of the bandgap will result in an enhanced current density. (2) Increase of Sb2S3 grain size by annealing will reduce the particle-to-particle hopping of the photo-induced carrier. This hopping may occur in an as-grown nanostructure with Sb2S3 nanoparticles. (3) Improvement of crystal quality of the Sb2S3 nanoparticles by annealing treatment will decrease the internal defects, which can reduce the recombination of photoexcited carriers and result in higher power conversion efficiency. (4) Good contact between the Sb2S3 nanoparticles and the TiO2 nanorod is formed as a result of high-temperature annealing.