Novel Morphology of Needle-Like Nanoparticles of Na2Mo2O7 Synthesized by Using Ultrasonic Spray Pyrolysis

Low-temperature method for the synthesis of novel morphology of needle-like nanoparticles of disodium dimolybdate (Na2Mo2O7) in the process of ultrasonic spray pyrolysis (USP) using aqueous solutions of thermodynamically stable molybdenum (VI) oxide clusters as precursor is described. Needle-like Na2Mo2O7 particles were obtained and collected in toluene, while centrifugation was employed to isolate solid material from solution. The scanning electron microscopy (SEM) confirmed that the morphology of the synthesized Na2Mo2O7 particles is needle-like collected into bundles. The X-ray Powder Diffraction (XRPD) analysis revealed appearance of orthorhombic Na2Mo2O7, synthesized at 300 °C. By comparing the XRPD pattern of the synthesized needle-like Na2Mo2O7 powder obtained in the process of USP with the XRPD pattern simulated for randomly-distributed crystallites by planes, the most prefered growth plane of needle-like nanoparticles were found

High-efficiency Sb2S3-based hybrid solar cell at low light intensity: cell made of synthesized Cu and Se-doped Sb2S3

Cu-doped (as p-doped) and Se-doped (as n-doped) Sb2S3 were synthesized from undoped Sb2S3 using a newly developed technique, simple colloidal synthesis method. X-ray diffraction measurements detected no peaks related to any of the Cu and Se compounds in Cu and Se-doped samples. Energy dispersive X-ray analysis, however, confirmed the presence of Cu and Se ions in the doped samples. Diffuse reflectance spectroscopy revealed the optical band gap energy changes because of doping effect, as reported for both the p-type and the n-type material. The valence-band X-ray photoelectron spectroscopy data showed a significant shift in the valence band to higher (Se-doped; +0.53eV) and a shift to lower (Cu-doped; -0.41eV) binding energy, respectively, when compared with the undoped sample. We report here on an inexpensive solar cell designed and made entirely of a synthesized material (indium tin oxide/p-doped Sb2S3+polyaniline (PANI)/amorphous/undoped Sb2S3+PANI/n-doped Sb2S3+PANI/PANI/electrolyte (0.5M KI+0.05M I-2)/Al). The cell has a high efficiency of 8% to 9% at a very low light intensity of only 5% sun, which makes it particularly suitable for indoor applications. As found, the cell performance at the intensity of 5% sun is governed by high shunt resistance (R-SH) only, which satisfies standard testing conditions. At higher light intensities (25% sun), however, the cell exhibits lower but not insignificant efficiency (around 2%) governed by both the series (R-S) and the R-SH. Minimal permeability in the UV region (up to 375nm) and its almost constant value in the visible and the NIR region at low light intensity of 5% sun could be the reasons for higher cell efficiency. Copyright (c) 2015 John Wiley and Sons, Ltd