Int. J. Hydrogen Energy. Vol. 10. No, 2, pp. 113--116. 1985.
0360--3199/85 $3.00 - (/,00
Printed in Great Britain
Pergamon Press Ltd.
International Association tor Hydrogen Energy
A ONE-UNIT PHOTOVOLTAIC ELECTROLYSIS SYSTEM BASED ON A
TRIPLE STACK OF AMORPHOUS SILICON (pin) CELLS
A. E. DEt.AHOV and S. C. GAu
Chronar Corporation, P.O. Box 177, Princeton, NJ 08542, U.S.A.
O. J. MURPHY, M. KAPu~ and J. O'M. BOCKRIs
Department of Chemistry, Texas A&M University College Station, TX 77843, U.S.A.
(Received 18 September 1984)
Abstract--An arrangement is suggested in one-unit photovoltaic electrolysis whereby the land area needed can
Considerable research efforts have been devoted to the
conversion of solar energy to a chemical fuel, e.g,
hydrogen, from the decomposition of water [1, 2]. Much
of this work has concentrated on photoelectrochemi-
cally based methods which, however, suffer from low
conversion efficiencies (<3%)
[3,4] and material
degradation problems . A small amount of attention
has been devoted to the coupling together of two or
more well-established technologies, namely p/n pho-
tovoltaic arrays and distant water electrolyzers [6, 7].
Although the latter approach gives rise to higher con-
version efficiencies, it suffers from the fact that two
plants are needed, and the intermediate generation of
amperage-low voltage electrical
Recently, an alternative method which combines the
site of collection of solar photons (using high-voltage
output photovoltaic cells) and the splitting of water into
one device has been successfully proven in this labora-
to'ry [8, 9]. Using single crystal GaAs cells, a solar
energy conversion efficiency to hydrogen of 8% was
achieved,  with no other energy input beyond
The present communication describes a new variation
of the one-unit photovoltaic electrolysis system which
utilizes a triple stack of amorphous silicon (pin) cells.
A diagramatic sketch of a practical