F. Galluzzi

Electrochemical solar cells with layer-type semiconductor anodes. Performance of n-MoSe2 cells

Abstract The output characteristics and the long-term performances of n -MoSe 2 (I − , I 2 ) electrochemical solar cells have been investigated. It has been confirmed that, by analogy with other layer-type, d-band transition metal dichalcogenide systems, the surface state of the semiconductor plays a key role in the behaviour of the cell. With ‘smooth’ crystal samples, fill factor and efficiency values of the order of 0.6 and 6%, respectively, have been obtained under AM1 illumination. Such performances are, however, drastically reduced if ‘irregular’ crystal samples are used. Control of these undesirable surface state effects has been attempted by chemical treatments specific to the unsaturated transition metal atoms exposed to the electrolyte at the edge sites. Finally, the stability of n -MoSe 2 I − , I 2 ) cells under long time operation, has also been evaluated.

Indium-doped CdS film on p-type silicon: An efficient heterojunction solar cell

Abstract An extensive study is presented on photovoltaic devices fabricated by the vacuum deposition of indium-doped CdS films onto p-type silicon substrates. Detailed investigations are reported of the electrical and photoelectric characteristics of these devices, of their dependence on the indium content of the window material and of the role of interfacial oxide layers. New results on the photovoltaic performance are also reported, showing that air mass 1 efficiencies higher than 11% and 9% can be reached on single-crystal and semicrystalline silicon substrates respectively, without using a back-surface field and antireflection coating. Possible improvements in cell efficiency are also discussed.

Contamination Effects in p-i-n Amorphous Silicon Solar Cells: Changes in the Characteristics of the Intrinsic Layer

The effect of contamination of intrinsic a-Si:H from dopant traces and “residual” impurities is investigated using various deposition conditions and apparatuses and monitoring the changes in optical, electrical and photo-electrical properties of intrinsic layers.

Stability and Efficiency in Amorphous Tandem Solar Cells

Theoretical evaluation of stability and efficiency of two-junction two-terminal amorphous tandem solar cells is performed using an analytical model which takes into account not only optical characteristics and transport properties but also photodegradation effects due to dangling bond formation under light exposure. Requirements for material quality and device design are particularly investigated.

Photovoltaic Performance of CdS Heterojunctions on Polycrystalline Silicon

New results on photovoltaic performance of n-CdS/p-Si heterojunctions are reported. Conversion efficiencies up to 11.1% for single crystal Si and 9.2% for semi-crystal Si have been obtained (without ARC and BSF) by a systematic study of CdS film doping, Silicon substrate preparation and interfacial oxide thickness.

Characterization of n-CdS/p-Si Heterojunction Solar Cells

Heterojunctions between silicon and transparent semiconductors are promising alternative solar cells. n-CdS/p-Si junctions, in particu lar, show Voc up to 570 mV,J up to 29 mA/cm2 and overall efficien cies up to 10% (without ARC). Transport mechanism in these devices can be described as a multistep thermal assisted tunneling, unchanged by illumination. Photoresponses show the expected band-pass behaviour with internal quantum yields of about 1.