Annealing Induced Shape Transformation of CZTS Nanorods Based Thin Films.

Here we studied the annealing induced shape transformation of 1D Cu2ZnSnS4 (CZTS) nanorods from nanospheres and nanocubes by simple sol-gel method without using any toxic chemicals or complicated vacuum based technology. X-ray diffraction pattern and Raman spectra reveal the formation of kesterite structure CZTS thin films. The energy dispersive X-ray analysis results indicate the presence of Cu, Zn, Sn, and S. The elemental distribution of all the CZTS samples was studied using elemental mapping. The Hall effect studies of the CZTS thin film composed of nanorods exhibits the lowest resistivity values which indicates efficient charge transfer for unidirectional structure. The obtained optical band gap energy of CZTS thin film is in the range of 1.46-1.54 eV, which is quite close to the optimum theoretical value required for solar cell applications.

Ball/dumbbell-like structured micrometer-sized Sb2S3 particles as a scattering layer in dye-sensitized solar cells.

To improve the light harvesting efficiency in dye-sensitized solar cells (DSSC) the light scattering layer is important. In this Letter, we present ball/dumbbell-like structured micrometer-sized Sb2S3 particles for photon propagation in DSSCs and demonstrate their effective usage in photoelectrodes. The analysis of the photoelectrode by a UV-vis spectrophotometer indicates that the absorption wavelength of an electrode with scattering layer can be obviously promoted from ultraviolet to visible light. The synthesized Sb2S3 particle structures were also characterized by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The photovoltaic performance of the ball/dumbbell-like structured Sb2S3 based cell exhibits excellent power conversion efficiency.

TiO2/AgO composites by one step photo reduction technique as electron transport layers (ETL) for dye-sensitized solar cells.

Dye-sensitized solar cell's electron transport layer is responsible for transporting photo-generated electrons to the outer circuit. Utilizing localized surface plasmon resonance (SPR), light absorption could be enhanced to a greater degree, which can drive dye molecules to excited state more effectively than far-field light. In this work, TiO2 nanoparticles were prepared by solvothermal method, and Ag nanoparticles were decorated over TiO2 surface through photodeposition method. XRD data of the TiO2 sample exhibits anatase phase and in the Ag nanoparticle decorated TiO2 sample, peaks corresponding to (111) planes of Ag was observed. UV-Vis absorption analysis of the TiO2 and Ag decorated TiO2 samples showed absorption in the UV region for the TiO2, and the SPR effect was detected for the Ag deposited TiO2 samples. Ag nanoparticles decorated over TiO2 was observed to be spherical in shape through the images from transmission electron microscope. Presence of both Ag and AgO in the prepared sample was revealed through the data from X-ray photoelectron spectroscopy. The prepared material was used as photoanodes in the construction of the DSSCs, and their performance was evaluated.

Natural dye sensitized TiO2 nanorods assembly of broccoli shape based solar cells.

TiO2 nanorods based thin films with rutile phase have been synthesized using template free low temperature hydrothermal method. The scanning electron microscope images showed that the prepared TiO2 samples were made of TiO2 nanorods and the nanorods had arranged by itself to form a broccoli like shape. The X-ray diffraction studies revealed that the prepared TiO2 samples exhibit rutile phase. The grown TiO2 nanorods had been sensitized using the flowers of Sesbania (S) grandiflora, leaves of Camellia (C) sinensis and roots of Rubia (R) tinctorum. Dye sensitized solar cells had been fabricated using the natural dye sensitized TiO2 nanorods based thin film photoelectrode and the open circuit voltage and short circuit current density were found to lie in the range of 0.45-0.6 V and 5.6-6.4 mA/cm(2) respectively. The photovoltaic performance of all the fabricated natural dye sensitized TiO2 solar cells indicate that natural dyes have the potential to be used as effective sensitizer in dye sensitized solar cells.

High-efficiency inverted organic solar cells with polyethylene oxide-modified Zn-doped TiO2 as an interfacial electron transport layer.

High efficiency inverted organic solar cells are fabricated using the PTB7:PC71BM polymer by incorporating Zn-doped TiO2 (ZTO) and 0.05 wt% PEO:ZTO as interfacial electron transport layers. The 0.05 wt% PEO-modified ZTO device shows a significantly increased power conversion efficiency (PCE) of 8.10%, compared to that of the ZTO (7.67%) device.