Photovoltaic cell

Claim 2

In a photovoltaic cell structure containing a transparent, electrically conductive metal oxide layer overlying a light-absorbing semiconductive photovoltaic layer, the improvement wherein a transparent, electrically conductive layer of titanium dioxide is between said metal oxide layer and said photovoltaic layer.

Claim 3

A structure as defined in claim 1, wherein said metal oxide layer is composed of an oxide of tin, indium, cadmium, zinc, or a mixture thereof.

Claim 4

A structure as defined in claim 2, wherein said metal oxide layer is composed of fluorine-doped tin oxide.

Claim 5

A structure as defined in claim 1, wherein said photovoltaic layer is composed of silicon, gallium arsenide, or indium phosphide.

Claim 6

A structure as defined in claim 4, wherein said photovoltaic layer is composed essentially of silicon.

Claim 7

A structure as defined in claim 1, wherein said layer of titanium dioxide is doped with fluorine, niobium, tantalum, tungsten, phosphorous, arsenic, antimony or vanadium, or mixtures thereof.

Claim 8

A structure as defined in claim 6, wherein said layer of titanium dioxide is doped with fluorine, niobium or tantalum.

Claim 9

A structure as in claim 1, wherein said layer of titanium dioxide has a sufficiently high electrical conductivity so that it contributes less than one ohm to the internal resistance of a solar cell of one square centimeter area.

Claim 10

A structure as in claim 1, wherein the electrical resistance of the cell is reduced by the presence of the titanium dioxide layer.

Claim 11

A structure as in claim 1, wherein the thermal stability of the cell is increased by the presence of the titanium dioxide layer.

Claim 12

A structure as in claim 1, wherein the reflectivity of the cell to light is reduced by the presence of the titanium dioxide layer.

Claim 13

A process of making an improved silicon photovoltaic cell comprising the step of placing a doped, electrically conductive, titanium oxide film on a photovoltaic silicon substrate and then overcoating said titanium oxide film with a thin, electroconductive layer of tin oxide.

Claim 14

A process of making an improved silicon photovoltaic cell comprising the step of placing a doped, electrically conductive, titanium oxide film on a photovoltaic silicon substrate and then overcoating said titanium oxide film with a thin, electroconductive layer of tin oxide.

Claim 15

A process as defined in claim 12 comprising the further step of decreasing the reflectivity of sunlight from said cell by overcoating said tin oxide with a transparent metal oxide of lower refractive index.

Claim 16

A process as defined in claim 13 wherein said refractive index of said metal oxide is about 1.4.

Claim 17

A process of operating a silicon-type solar cell to achieve enhanced light-receiving efficiency comprising the steps of (1) providing, between a photovoltaic silicon material and incident radiation, a transparent electroconductive structure which is free of metallic conductor members, and (2) separating said silicon material from an overlying electroconductive SnO 2 layer by a thin layer of electroconductive titanium oxide, and (3) providing a thin layer of a relatively low refractive index material over said electroconductive SnO 2 as means to further reduce reflectivity of said cell.

Claim 18

A process of operating a silicon-type solar cell to achieve enhanced light-receiving efficiency comprising the steps of (1) providing, between a photovoltaic silicon material and incident radiation, a transparent electroconductive structure which is free of metallic conductor members, and (2) separating said silicon material from an overlying electroconductive SnO 2 layer by a thin layer of electroconductive titanium oxide, and (3) providing a thin layer of a relatively low refractive index material over said electroconductive SnO 2 as means to further reduce reflectivity of said cell.