Process for electrolytically preparing a semiconducting film on a flexible substrate

Claim 3

A method for the preparation of a film according to claim 1 wherein the colloidal particles have an average diameter between 5 nm and 35 nm.

Claim 4

A method for the preparation of a film according to claim 1 wherein the colloidal particles are negatively charged.

Claim 5

A method for the preparation of a film according to claim 1 wherein the organic liquid has a dielectric constant greater than 10.

Claim 6

A method for the preparation of a film according to claim 1 wherein a starting material for the preparation of the semiconductor is gaseous.

Claim 7

A method for the preparation of a film according to claim 1 wherein the pH of the colloidal suspension is between 3.0 and 8.0.

Claim 8

A method for the preparation of a film according to claim 1 wherein the colloidal suspension contains a stabiliser.

Claim 9

A method for the preparation of a film according to claim 38 wherein the colloidal suspension contains a dopant.

Claim 10

A method for the preparation of a film according to claim 1 wherein the colloidal suspension contains a binding agent.

Claim 11

A method for the preparation of a film according to claim 1 wherein the said substrate is a working electrode in an electrical circuit.

Claim 12

A method for the preparation of a film according to claim 10 wherein the said working electrode is an anode.

Claim 13

A method for the preparation of a film according to claim 11 wherein the working electrode is planar and a counter electrode in the form of a wire is present.

Claim 14

A method for the preparation of a film according to claim 1 wherein the semiconductor after deposition on the said surface is heat treated.

Claim 15

A method for the preparation of a film according to claim 13 wherein heating is effected by gaseous ion bombardment.

Claim 16

A thin substantially pin-hole-free film of a semiconducting sulphide, sulphoselenide, selenide or telluride prepared according to claim 1.

Claim 17

A thin substantially pin-hole-free film as claimed in claim 15 containing a dopant.

Claim 18

A laminate comprising a thin substantially pin-hole-free film as claimed in claim 15 and a substrate, on a surface of which the said film has been electrophoretically deposited.

Claim 19

An electronic device comprising a film as claimed in claim 15 and at least one means for conducting current in electrical contact therewith.

Claim 20

A method for the preparation of a solar cell comprising the steps of preparing a thin substantially pin-hole-free first film of a semiconducting sulphide, sulphoselenide, selenide or telluride, and forming a metal/semiconductor or a p/n junction between the first film and a second film comprising a metal or a semiconductor having majority charge carriers of opposite electronic charge to the majority charge carriers in the first film, the first film being in electrical contact with a first current conducting means and the second film, where it is a semiconductor, being in electrical contact with a second current conducting means at least one of the current conducting means allowing radiation incident thereon to penetrate to the junction, characterized in that the first film is prepared by a process as claimed in claim 1.

Claim 21

A method for the preparation of a solar cell as claimed in claim 19 wherein the first film is electrophoretically deposited on the first current conducting means.

Claim 22

A method for the preparation of a solar cell as claimed in claim 19 wherein the junction is a p-n junction.

Claim 23

A method for the preparation of a solar cell as claimed in claim 21 wherein the junction is a heterojunction.

Claim 24

A method for the preparation of a solar cell as claimed in claim 22 wherein the second film comprises a compound based on monovalent cations selected from Group IB of the Periodic Table.

Claim 25

A method for the preparation of a solar cell as claimed in claim 23 wherein the monovalent cation is copper.

Claim 26

A method for the preparation of a solar cell as claimed in claim 24 wherein the second film comprises copper (I) sulphide.

Claim 27

A method for the preparation of a solar cell as claimed in claim 19 comprising the step of heating the junction to improve electrical contact between the films.

Claim 28

A method for the preparation of a solar cell as claimed in claim 19 comprising the step of providing an antireflection coating to reduce or prevent the reflection of incident radiation from the surface of the film which is to be subjected to incident radiation.

Claim 29

A method for the preparation of a solar cell as claimed in claim 19 comprising the step of providing means to prevent or reduce the ingress of oxygen and/or water into the cell, said means allowing electrical contact to be made between the said current conducting means and an electrical circuit external to the cell.

Claim 30

A solar cell prepared according to a method as claimed in claim 19.

Claim 31

A method as in claim 1 wherein the flexible carrier is a film of a thermoplastic material.

Claim 32

A method as in claim 30 wherein the thermoplastic material is selected from the group consisting of polyethylene terephthalate, polyethersulphone and polyimide.

Claim 33

A method as in claim 1 wherein the substrate is in the form of a strip which is progressively transported through the said colloidal suspension to effect continuous deposition.