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High-haze and wide-spectrum hydrogenated Mg and Ga co-doped ZnO (HMGZO) transparent conductive oxide films on ‘U-shaped’ micro-textured glass are developed using magnetron sputtering. The wet-chemically etched glass substrates with large crater-like features obtained via a frosting method exhibit strong light-scattering capability in a wide wavelength range (~350–1100 nm). The morphological, structural, optical and electrical properties of HMGZO films on textured and flat glass are investigated in detail. The HMGZO thin films deposited on textured glasses show conformal growth and have a polycrystalline hexagonal wurtzite phase with a c -axis preferred orientation, which is similar to that of films deposited on flat glass. The electrical resistivity of HMGZO films decreases from 9.74×10 −4 to 7.67×10 −4 Ω cm and the optical band gap E g is in the range from 3.76 to 3.72 eV as the deposition time is increased from 25 to 40 min. The HMGZO films with textured glass substrate exhibit stronger light-scattering capability compared with films with flat glass substrate. Finally, an a-Si solar cell deposited on textured glass shows a higher conversion efficiency and short-circuit current density than that deposited on flat glass, as a result of effectively improved light scattering. ZnO-TCO films on low-cost chemically etched glass substrates are promising candidates as front electrodes for thin-film solar cells. [ABSTRACT FROM AUTHOR]

Textured surface zinc oxide (ZnO) transparent conductive oxide (TCO) films with modulated structure have been fabricated using metal organic chemical vapor deposition (MOCVD) on superwhite glass substrates. It was found that gradient boron-doping growth for ZnO films can improve the pyramid-like grain sizes with strong light-scattering capability and optical transparences in near infrared (NIR) region resulting from decreased carrier concentration absorption. Furthermore, ZnO-TCO film with sandwich structure (boron-doped ZnO (ZnO:B)/un-doped ZnO/boron-doped ZnO (ZnO:B)) exhibited relatively higher electron mobility and higher optical transmittances as well as haze values in the wavelength range of 750–1800 nm than the conventional ZnO:B sample. [ABSTRACT FROM AUTHOR]

Transparent conductive hydrogenated Mg and Ga co-doped ZnO (HMGZO) thin films for solar cells were deposited via pulsed direct current (DC) magnetron sputtering on glass substrates at a substrate temperature of 553K. The structural, morphological, electrical, and optical properties of HMGZO thin films were investigated with various H2 flow rates. The experiment results showed that the HMGZO thin films are polycrystalline with a hexagonal wurtzite structure exhibiting a preferred (002) crystal plane orientation and typical HMGZO thin films present cone-like texture surface. The carrier concentration rapidly increases from 7.57×1019 cm−3 to 5.25×1020 cm−3 with increasing the H2 flow rate from 0sccm to 4.0sccm. Optical measurements indicated that the optical band-gap (E g ) of HMGZO thin films varies from 3.43eV to 3.66eV with adjusting H2 flow rate from 0sccm to 4.0sccm. The glass/HMGZO thin film deposited at the H2 flow rate of 4.0sccm exhibits the lowest resistivity of 6.24×10−4 Ωcm (sheet resistance Rs~8.68Ω) and an average transmittance (Ta) of 78.8% in the wavelength range from 340nm to 1100nm. Burstein–Moss band-filling, band gap renormalization effects determined by carrier concentrations and the incorporation of Mg atoms together contribute to an E g widening phenomenon. The electron mobility of HMGZO thin films can be effectively improved through thermal annealing process. Finally, the HMGZO thin film was preliminarily applied in pin a-Si:H thin film solar cell with an efficiency of 8.20% (V oc =0.904V, J sc =12.906mA/cm2 and FF=0.702). [ABSTRACT FROM AUTHOR]

Abstract: Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. These natively textured HGZO thin films exhibit rough pyramid-like textured surface, high optical transmittances in the visible and near infrared region and excellent electrical properties. The experiment results indicate that tungsten-doped indium oxide (In2O3:W, IWO) buffer layers can effectively improve the surface roughness and enhance the light scattering ability of HGZO thin films. The root-mean-square roughness of HGZO, IWO (10nm)/HGZO and IWO (30nm)/HGZO thin films are 28, 44 and 47nm, respectively. The haze values at the wavelength of 550nm increase from 7.0% of HGZO thin film without buffer layer to 18.37% of IWO (10nm)/HGZO thin film. The optimized IWO (10nm)/HGZO exhibits a high optical transmittance of 82.18% in the visible and near infrared region (λ ~400–1100nm) and excellent electrical properties with a relatively low sheet resistance of 3.6Ω/□ and the resistivity of 6.21×10−4 Ωcm. [Copyright &y& Elsevier]

Highlights: [•] W-doped ZnO (WZO) films were deposited by reactive magnetron sputtering. [•] Substrate temperatures have key influences on the properties of WZO films. [•] Low sheet resistance and high transmittance were obtained at 300°C. [•] W element exists only in the oxidized state of W6+ in WZO thin films. [•] WZO films are promising TCO layers for solar cells. [ABSTRACT FROM AUTHOR]

Abstract: Natively textured surface aluminum-doped zinc oxide (ZnO:Al) layers for thin film solar cells were directly deposited without any surface treatments via pulsed direct-current reactive magnetron sputtering on glass substrates. Such an in-situ texturing method for sputtered ZnO:Al thin films has the advantages of efficiently reducing production costs and dramatically saving time in photovoltaic industrial processing. High purity metallic Zn–Al (purity: 99.999%, Al 2.0wt.%) target and oxygen (purity: 99.999%) were used as source materials. During the reactive sputtering process, the oxygen gas flow rate was controlled using plasma emission monitoring. The performance of the textured surface ZnO:Al transparent conductive oxides (TCOs) thin films can be modified by changing the number of deposition rounds (i.e. thin-film thicknesses). The initially milky ZnO:Al TCO thin films deposited at a substrate temperature of ~553K exhibit rough crater-like surface morphology with high transparencies (T ~80–85% in visible range) and excellent electrical properties (ρ ~3.4×10−4 Ωcm). Finally, the textured-surface ZnO:Al TCO thin films were preliminarily applied in pin-type silicon thin film solar cells. [Copyright &y& Elsevier]

Abstract: A novel method to prepare inorganic–organic hybrid with villus-like morphology comprising a layer of silica nanoparticles adsorbed on polymethylmethacrylate (PMMA) microsphere was presented in this article. At first, silica nanoparticles were surface treated with vinyltriethoxysilane (VTEOS), and then a wet grinding process with VTEOS as the dispersing agent was utilized to prevent the aggregation of nanoparticles. Zeta-potential measurements confirmed that the surface charge of these milled silica is negative. On the other hand, positively charged PMMA was prepared by adsorption of 2-(methacryloyloxy) ethyl-trimethyl ammonium chloride (METMAC) on as-synthesized PMMA beads. Owing to the electrostatic interaction, the negatively charged silica particles were coated directly on the surface of positively charged PMMA microspheres. The hybrid is fully covered by a layer of silica and the silica content is 18.5%. From our results, it is evident that the villus silica layer adhered on the PMMA bead surfaces and it significantly enhanced the thermal stability of the hybrid microspheres. The characteristics and morphologies of the silica particles, PMMA beads and the resulting PMMA/silica hybrids were investigated by SEM, TEM, FESEM, EDS, FTIR, TGA, and aging analysis. [Copyright &y& Elsevier]

Boron-doped ZnO (BZO) films deposited by metal organic chemical vapor deposition (MOCVD) generally act as transparent conductive oxide films in hydrogenated amorphous silicon (a-Si:H) solar cells and exhibit a high external quantum efficiency (EQE) performance in the short-wavelength region. They, therefore, facilitate efficient use of sunlight in solar cells. However, sharp surface features on the BZO film may result in nano-cracks and voids in the cells. In this study, we devised a process for modifying these sharp features. The BZO films were smoothened by performing a sputtering hydrogen-doped ZnO (HZO) layer using a magnetron sputtering system. The a-Si:H solar cells based on BZO films subjected to this treatment exhibited a higher open-circuit voltage ( V oc ), fill factor ( FF ), and efficiency; however, their short-circuit current density ( J sc ) decreased slightly. In an attempt to increase the J sc while maintaining a high electrical performance for the solar cells, we deposited an additional thin BZO film on the sputter-treated one to realize a micro- and nano-textured structure. This strategy succeeded in increasing J sc and also caused a further improvement in the V oc , FF , and efficiency. As a result, over 10% efficiency of a-Si:H solar cells based on BZO electrodes with a micro- and nano-textured structure was achieved. Moreover, the thickness of the cell is only 300 nm. [ABSTRACT FROM AUTHOR]

Abstract: A simple and efficient activation process was conducted by deposition of palladium (Pd) nanoparticles on PMMA surface using a microwave-assisted polyol method with ethanol used as the reductant. The newly synthesized Pd nanoparticles were utilized as an activator for electroless nickel deposition. TEM images revealed that Pd nanoparticles of size 4–6nm are formed evenly over the PMMA surface. A tight, smooth and continuous Ni plating layer was coated on these Pd nanoparticle activated PMMA microspheres. In contrast, a rough and discontinuous Ni film was obtained for the sample activated with a conventional sensitization/activation procedure. [Copyright &y& Elsevier]