Eva Magnusson

A 5% efficient photoelectrochemical solar cell based on nanostructured ZnO electrodes

Nanoporous ZnO electrodes, dye-sensitized with a ruthenium bipyridyl complex, were used as photoanodes in photoelectrochemical solar cells. By improving the interfacial contact between dyes and ZnO particles in the film, overall solar-to-electric energy conversion efficiencies of up to 5% were obtained. The solar cell performance was studied as a function of film thickness, residence time of the electrodes in the dye solution, electrolyte composition and light intensity.

A new method to make dye-sensitized nanocrystalline solar cells at room temperature

This paper describes a new method for manufacturing a nanostructured porous layer of a semiconductor material at room temperature. The porous layer is pressed on a conducting glass or plastic substrate for use in a dye-sensitized nanocrystalline solar cell. The method compresses the particle layer to form a mechanically stable, electrically conducting, porous nanostructured film. Overall, solar to electric conversion efficiencies of up to 5.2% at 0.1 sun using plastic substrates have been obtained.

A new method for manufacturing nanostructured electrodes on glass substrates

The present paper describes a new method for manufacturing a nanostructured porous layer of a semiconductor material on a conducting plastic substrate for use in an electrochemical or photoelectrochemical cell. The method involves the deposition of a layer of semiconductor particles on conducting plastic and the compression of the particle layer to form a mechanically stable, electrically conducting, porous nanostructured film at room temperature. Photoelectrochemical characteristics of the resulting nanostructured films are presented showing, for example, overall solar to electric conversion efficiencies of up to 4.9% (0.1 sun). The potential use of the new manufacturing method in future applications of nanostructured electrodes is discussed.

Nanocrystalline Ti-oxide-based solar cells made by sputter deposition and dye sensitization: Efficiency versus film thickness

Nanocryst. TiO2-based films with a special penniform microstructure were prepd. by reactive d.c. magnetron sputtering followed by dye sensitization. The films were integrated in a solar cell configuration and were able to yield a higher photocurrent than sol-gel-produced titanium oxide-based films of similar thickness. The photoelec. conversion efficiency reached 4% in ∼10-μm-thick sputter deposited films.

The effects of controlled muscle tension on performance and learning of heart-rate control

Thirty female subjects were divided in three groups and instructed in group I to increase their HRs with the aid of continuous feedback of performance, while they tensed their right forearm muscles 20% of maximal voluntary contraction. In the last session only feedback was used, Group II were trained with feedback only. Group III for the first two sessions tensed their muscles only, and in the last session trained HR increases with feedback only. Group I was superior in HR performance in the first two sessions. In the third session they deteriorated significantly and could not be distinguished from the other two groups. The results were interpreted in terms of relations between somatic and autonomic events and transfer between different states of somatic involvement during learning. Electrodermal activity and respiration were included as control variables.

Physiological response patterns during ‘intake’ and ‘rejection’ tasks

Two 2-min tasks, one requiring outer-directed attention (intake task), the other a mental arithmetic task (rejection task) were presented to 20 subjects. According to Lacey the distinguishing feature of the response to intake tasks are cardiac deceleration and blood pressure decreases. None of these responses was obtained. Some variables, however, were only affected by one of the tasks; the intake task led to a decreased hand (skin) blood flow and an increased hand vascular resistance, whereas a heart rate acceleration and increased forearm (muscle) blood flow and decreased forearm vascular resistance were observed during the rejection task. Blood pressure, respiration rate and skin conductance were similarly affected by the two tasks. Inconsistencies among previous studies of the response to the two types of tasks were discussed and found to be partially explained by methodological differences.

Heart rate control and aversive stimulation

College students were required to train heart rate control (heart rate increase and decrease) with visual feedback for three sessions in a within-person design. In the second and third sessions a test period was added when electric shocks were delivered during half in the trials. Subjects had been grouped in advance in an Aware and an Unaware group on the basis of the Automatic Perception Questionnaire (APQ). The results contradicted some findings by other authors which claim that biofeedback can be used to ameliorate subjective effects of aversive stimulation. Alternative interpretations of the discrepant findings were discussed in terms of expectancy effects that may influence autonomically Aware subjects more strongly than Unaware subjects.