Chemical liquid deposition of CuInSe2 and CuIn(S,Se)2 films for solar cells

Several non-vacuum based approaches have been employed to deposit the Cu(In,Ga)Se₂ layer in photovoltaic devices, but most of them use processing temperatures in the vicinity of 500 °C. Here, we present the results on a facile solution-based deposition technique for CuInSe₂ (CISe) and CuIn(S,Se)₂ (CISSe) thin films with deposition temperatures of 300 °C. Cu_xSe (1.5 ≤ x ≤ 2) or Cu_yS (1 ≤ y ≤ 2) precursor films deposited on a substrate were reacted with InCl₃ and Se reactants in oleylamine to form CISe or CISSe thin films of the desired thickness, composition and crystal structure. Solar cells processed from these films on Mo-coated glass substrates demonstrated an efficiency of 2% under AM 1.5 illumination. We also present external quantum efficiency and capacitance-voltage measurements from these devices providing insights into the device performance.     

Silk Materials – A Road to Sustainable High Technology

This review addresses the use of silk protein as a sustainable material in optics and photonics, electronics and optoelectronic applications. These options represent additional developments for this technology platform that compound the broad utility and impact of this material for medical needs that have been recently described in the literature. The favorable properties of the material certainly make a favorable case for the use of silk, yet serve as a broad inspiration to further develop biological foundries for both the synthesis and processing of Nature's materials for technological applications.     

Flexible Field Emission from Thermally Welded Chemically Doped Graphene Thin Films

Flexible field‐emission devices (FEDs) based on reduced graphene oxide (RGO) emitters are fabricated by the thermal welding of RGO thin films onto a polymeric substrate. The RGO edges are vertically aligned relative to the substrate as a result of cohesive failure in the RGO layer after thermal welding. Even at large bending angles, excellent electron emission properties, such as low turn‐on and threshold fields, a high emission current density, a high field enhancement factor, and long‐term stability of the emission properties of RGO emitters, arise from the uniform distribution and high density of the extremely sharp RGO edges, as well as the high interfacial strength between the RGO emitters and the substrate. Al‐ and Au‐doped RGO emitters are fabricated by introducing a dopant solution to the RGO emitters, and the resulting field‐emission characteristics are discussed. The proposed approach is straightforward and enables the practical use of high‐performance RGO flexible FEDs.     

High-damping carbon nanotube hinged micromirrors

New developments in digital mirror devices (DMDs) require suspension hinges with a good damping and high temperature stability. Carbon nanotubes (CNTs) offer these unique properties. Herein it is shown how CNT hinges can be integrated in micromirrors. The image illustrates a micromirror with a CNT suspension, and a typical overdamped stepresponse (Q-factor < 0.5).