Aluminium-doped zinc oxide (AZO) is a common material used as a front contact layer on chalcopyrite CuInGaSe2 (CIGS)-based thin-film solar cells since it combines optimum optical and electrical properties with low cost and abundant elemental availability. Low-resistivity and high-transmission front contacts are required to develop high-performance CIGS solar cells. However, the durability of the cells is highly influenced by the corrosion resistance behaviour of the AZO layers. In this work, an exhaustive study of the aluminium-doped zinc oxide layers (AZO) deposited by pulsed DC magnetron sputtering (MS) has been performed. The optical, electrical and electrochemical corrosion resistance properties of the AZO layers have been evaluated as a function of the deposition pressure. The results show that adjusting the deposition pressure could develop AZO layers with very high electrochemical corrosion resistance in chlorinated aqueous media combined with optimum electrical and optical properties. Layers grown at 3×10−3mbar pressure present very high corrosion resistance values (in the order of 106 {\$}Ømega{\$}) and very high electrochemical stability, indicating no tendency for electrochemical corrosion degradation. Besides, these layers are highly transparent with an average transmittance in the visible range above 90{%} and with a low resistivity of 6.8×10−4 {\$}Ømega{\$}cm for a 1000nm films thickness, making them optimum candidate front contact for high-performance and high durability CIGS solar cells.

Cotton-based nanocrystalline cellulose (NCC), also known as nanopaper, one of the major sources of renewable materials, is a promising substrate and component for producing low cost fully recyclable flexible paper electronic devices and systems due to its properties (lightweight, stiffness, non-toxicity, transparency, low thermal expansion, gas impermeability and improved mechanical properties). Here, we have demonstrated for the first time a thin transparent nanopaper-based field effect transistor (FET) where NCC is simultaneously used as the substrate and as the gate dielectric layer in an ‘interstrate' structure, since the device is built on both sides of the NCC films; while the active channel layer is based on oxide amorphous semiconductors, the gate electrode is based on a transparent conductive oxide. Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility ({\textgreater}7 cm 2 V −1 s −1 ), drain–source current on/off modulation ratio higher than 10 5 , enhancement n-type operation and subthreshold gate voltage swing of 2.11 V/decade. The NCC film FET characteristics have been measured in air ambient conditions and present good stability, after two weeks of being processed, without any type of encapsulation or passivation layer. The results obtained are comparable to ones produced for conventional cellulose paper, marking this out as a promising approach for attaining high-performance disposable electronics such as paper displays, smart labels, smart packaging, RFID (radio-frequency identification) and point-of-care systems for self-analysis in bioscience applications, among others.