Structural and electrical properties of highly conductive μc-Si(P) layers

Thin films of phosphorus doped μc-Si have been prepared in a glow discharge reactor starting from hydrogen diluted silane using less than 5 watt RF power. Conductivities as high as 41 S/cm have been measured on samples deposited at 210°C. The discharge parameters and reactor geometry will be examined in order to correlate the really dissipated RF power to the structural and electrical properties of the material. XRD, SEM, Raman spectroscopy and electrical characterization techniques have been used. All the samples show clusters that increase with the film thickness, while at the same time the crystallite size changes in the range 30–75 Å

Thin film silicon photovoltaics: Architectural perspectives and technological issues

Thin film photovoltaics is a particularly attractive technology for building integration. In this paper, we present our analysis on architectural issues and technological developments of thin film silicon photovoltaics. In particular, we focus on our activities related to transparent and conductive oxide (TCO) and thin film amorphous and microcrystalline silicon solar cells. The research on TCO films is mainly dedicated to large-area deposition of zinc oxide (ZnO) by low pressure-metallorganic chemical vapor deposition. ZnO material, with a low sheet resistance ( 82%) in the whole wavelength range of photovoltaic interest, has been obtained. "Micromorph" tandem devices, consisting of an amorphous silicon top cell and a microcrystalline silicon bottom cell, are fabricated by using the very high frequency plasma enhanced chemical vapor deposition technique. An initial efficiency of 11.1% (>10% stabilized) has been obtained.Renewable energy Thin film silicon photovoltaics Building integrated photovoltaics Micromorph solar cells

Development of SnO2 Composites as Electron Transport Layer in Unencapsulated CH3NH3PbI3 Solar Cells

Improving morphological and electronic properties of the electron transport layer (ETL) is a critical issue to fabricate highly efficient perovskite solar cells. Tin dioxide is used as an ETL for its peculiarities such as low-temperature solution-process and high electron mobility and several handlings have been tested to increase its performances. Herein, SnO2:ZnO and SnO2:In2O3 composites are studied as ETL in planar n-i-p CH3NH3PbI3 solar cells fabricated in ambient air, starting from glass/ITO substrates. Morphological, electrical and optical properties of zinc- and indium-oxide nanoparticles (NPs) are investigated. First-principle calculations are also reported and help to further explain the experimental evidences. Photovoltaic performances of full devices show an improvement in efficiency for SnO2:In2O3–based solar cells with respect to pristine SnO2, probably due to a suppression of interfacial charge recombination between ITO/ETL and ETL/perovskite. Moreover, a better homogeneity of SnO2:In2O3 deposition with respect to SnO2:ZnO composites, conducts an increase in perovskite grain size and, consequently, the device performances