Multi-layer film electrodes

Fig. 20.1. MAC Mode AFM three-dimensional images in air of (A) clean HOPG electrode (B) thin-film dsDNA-biosensor surface, prepared onto HOPG by 3 min free adsorption from 60 pg/mL dsDNA in pH 4.5 0.1 M acetate buffer (C) multi-layer film dsDNA biosensor, prepared onto HOPG by evaporation of three consecutive drops each containing 5pL of 50 pg/mL dsDNA in pH 4.5 0.1 M acetate buffer (D) thick-film dsDNA biosensor, prepared onto HOPG by evaporation from 37.5mg/mL dsDNA in pH 4.5 0.1M acetate buffer. With permission from Refs. [28,29].

Electrodes and cell components must be thin to minimise the internal resistance of the batteries the total cell can be less than 0.2 mm thick. Figure 12.11 shows the construction of a multi-layer film, rechargeable lithium polymer battery, using a solid polymer electrolyte. A thin lithium metal foil acts as an anode. The electrolyte is polyethylene oxide containing a lithium salt, and the cathode is a composite of the electrolyte and a... 

Figure 2.82 (a) Reflectivity of Cu-on-Si electrode at various potentials in borate buffer solution (pH 8.4). A.B.C and D correspond to potentials indicated in the cyclic voltammogram of Figure 2.81(b). Solid lines represent calculated curves while symbols correspond to experimental data, Open circles, A, -0,12 V open squares, B, -0.80V both y-axes are reflectivity x 10". Filled circles, C, 0.40 V, reflectivity x 10" 3 open diamonds, D, —0.80 V, reflectivity x 10 s. (b) Schematic of multi-layer mode) for Cu-on-Si electrode (not to scale). The oxide film is represented as Cu20. From Melendres et ai (1991). 

A complete coverage of the electrode surface is obtained using the multi-layer and thick dsDNA films described in Procedure 28 (see in CD... 

Periodic nanostructured layers promise wide applications in electronic and optoelectronic devices. Photoelectrochemical and electrochromic structures are among them [1]. The most suitable process for formation of such layers is electrochemical anodization of tantalum-aluminum multi-layer thin-fllm compositions. This process is inexpensive and permits to form nanostructured pillar layers of Ta205 with large surface area. Details of Ta20s pillar formation from two-layer Al/Ta thin film compositions were described in our previous papers [2,3]. The main purpose of our further investigations was to investigate the processes of anodization of a multi-layer Al/Ta/Al structure. It was found that application of the bottom A1 layer improves uniformity of nanostructured pillar layers due to more homogeneous current supply. Besides, this layer serves as an electrode of a metal/dielectric/metal (MDM) sfructure. Furthermore, such metals as Nb and Ti may be used instead of Ta layer. 

Using multi-layers of sensitizer does not offer a viable solution to this problem. Only the molecules that are in direct contact with the oxide surface would be photoactive - the remainder filtering merely the light. Apart from poor light harvesting a compact semiconductor film would need to be n-doped to conduct electrons. In this case energy transfer quenching of the excited sensitizer by the electrons in the semiconductor would inevitably reduce the photovoltaic conversion efficiency. For this reason the conversion yields obtained from the sensitization of flat electrodes... 

---