Apcvd of doped titanium oxide and the coated article made thereby

Abstract

A method of making a doped titanium oxide coating in a float glass manufacturing process and the coated glass article made thereby wherein the dopant is a niobium or tantalum compound. The doped titanium oxide coating preferably exhibits an electrical conductivity > 1×10 −3 S/cm.

What is claimed is: 
     
         1 . A method of making a doped conductive titanium oxide coating by atmospheric chemical vapor deposition during a glass manufacturing process comprising:
 providing a heated glass ribbon in a float glass process;   providing a uniform precursor gas mixture comprising a halogenated, inorganic titanium compound, a halogenated, inorganic niobium or tantalum dopant compound, an organic oxygen-containing compound and one or more inert carrier gases, wherein the halogenated, inorganic niobium or tantalum dopant compound comprises no more than 0.3 mol % of the precursor gas mixture;   delivering the precursor gas mixture at a temperature below the thermal decomposition temperature of the precursor gas mixture to a location adjacent the heated glass ribbon to be coated, the float bath atmosphere surrounding the heated glass ribbon being at essentially atmospheric pressure; and   bringing the precursor gas mixture into coating contact with the heated glass ribbon, the temperature of the heated glass ribbon being sufficient to cause reaction of the precursor gas mixture so as to deposit a doped titanium oxide coating at a deposition rate greater than 35 Å/sec. on the glass ribbon, the doped titanium oxide coating exhibiting an electrical conductivity of greater than 1×10 −3  S/cm.   
     
     
         2 . The method defined in  claim 1 , wherein the glass ribbon is at a temperature of 1050° F. (566 C)-1350° F. (732 C). 
     
     
         3 . The method defined in  claim 1 , wherein the halogenated inorganic titanium compound comprises TiCl 4 . 
     
     
         4 . The method defined in  claim 1 , wherein the halogenated inorganic dopant compound comprises one chosen from the group consisting of: NbF 5 , NbCl 5 , TaF 5 , and TaCl 5 . 
     
     
         5 . The method defined in  claim 4 , wherein the halogenated inorganic dopant compound comprises NbF 5 . 
     
     
         6 . The method defined in  claim 1 , wherein the organic oxygen containing compound comprises an organic ester. 
     
     
         7 . The method defined in  claim 6 , wherein the organic ester comprises ethyl acetate. 
     
     
         8 . The method defined in  claim 4 , wherein the precursor mixture comprises no more than 0.3 mol % NbF 5 . 
     
     
         9 . The method defined in  claim 1 , wherein the deposition rate of the doped titanium oxide is greater than 75 Å/sec. 
     
     
         10 . The method defined in  claim 1 , wherein the conductivity exhibited by the doped titanium oxide coating is more than 3.54E −2 S/cm. 
     
     
         11 . The method defined in  claim 1 , wherein the inert carrier gas is comprised of one or more of He, N, H 2  and mixtures thereof. 
     
     
         12 . A coated glass article comprising:
 a glass substrate;   a coating deposited over the glass substrate comprising:
 a titanium oxide layer having a thickness from 500 Å to 1500 Å doped with a halogenated niobium or tantalum compound; 
   the doped titanium oxide coating exhibiting an electrical conductivity greater than 1×10 −3  S/cm.   
     
     
         13 . A solar cell comprising the coated glass article of  claim 12 . 
     
     
         14 . The coated glass article defined in  claim 12  comprising:
 a glass substrate; 
 a color suppression coating deposited over the glass substrate comprising:
 an undoped tin oxide layer having a thickness of 250 Å-600 Å; 
 a silica layer having a thickness of 250 Å-350 Å; 
 a doped tin oxide layer; 
 a doped titanium oxide layer having a thickness of from 500 Å to 1500 Å, the dopant comprising no more than 0.3 mol % of a halogenated niobium or tantalum compound, which coating exhibits an electrical conductivity greater than 1×10 −3  S/cm; and 
 one or more amorphous silicon layers. 
 
 
     
     
         15 . A solar cell comprising the coated glass article of  claim 14 .