Synthesis of Sb2S3 Nanowires and Their Application in Hybrid Solar Cells

High quality Sb2S3 nanowires, which were 60-70 nm in diameter and 4-6 mu m in length, were synthesized via a facile solvothermal approach by using L-cysteine (C3H7 NO2S) as a capping agent, and applied to hybrid solar cells after blending with poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). The as-synthesized nanowires were characterized by XRD, SEM, TEM, UV-Vis absorption and PL spectra; the solar cells were investigated by current-voltage (J-V) measurements and incident photon-to-current conversion efficiency(IPCE) spectroscopy. The highly pure Sb2S3 nanowires have a bandgap of 1.57 eV and grow along [001] direction. In comparison with the solar cells without Sb2S3 nanowires, the MEH-PPV/Sb2S3 devices exhibit a much higher J(sc) depending on the Sb2S3 concentration and a certain wide spectral response characteristics due to complementary absorption of Sb2S3 nanowires. With addition of the Sb2S3 nanowires into the polymer phase, the MEH-PPV/Sb2S3 interfaces are created for dissociation of the excitons generated in the polymer and the direct channels are formed for electron transport; on the other hand, the defects on the nanowire surface cause the serious charge recombination that is unfavorable for the photocurrent generation. At the Sb2S3/MEH-PPV mass ratio of 5 : 1, the device with a power conversion efficiency of 0.393% is achieved under AM 1.5 illumination(100 mW/cm(2))