Conformally coated wire array photoelectrodes for photoelectrochemical fuel generation

Abstract

Embodiments of the present invention are directed to photoelectrodes having a wire array core and a conformal coating on the core. The wire array core and the conformal coating can be independently selected from inorganic semiconductor materials. The photoelectrodes can be used as either or both the anode and cathode in a device for fuel generation. Such a device, for example, could include a photoanode and a photocathode separated from each other by an electrically and ionically permeable, and proton-conductive membrane.

What is claimed is: 
     
         1 . A device for photoelectrochemical fuel generation, comprising an electrode comprising:
 a core comprising an array of wires, the wires comprising a first inorganic semiconductor material; and   a conformal coating on the array of wires of the core, the conformal coating comprising a second inorganic semiconductor material.   
     
     
         2 . The device according to  claim 1 , wherein each of the first and second inorganic semiconductor materials is independently selected from the group consisting of Group IV elemental semiconductors, Group IV compound semiconductors, III-V semiconductors, and II-VI semiconductors. 
     
     
         3 . The device according to  claim 1 , wherein the first inorganic semiconductor material comprises Si, Ge, SiGe alloys, GaP, GaAs x P 1-x  alloys, GaAs x N y P 1-x-y  alloys, and WO 3 . 
     
     
         4 . The device according to  claim 2 , wherein the second inorganic semiconductor material is different from the first inorganic semiconductor material and comprises GaP, a GaAs x P 1-x  alloy, a GaAs x N y P 1-x-y  alloy, or WO 3 . 
     
     
         5 . The device according to  claim 1 , wherein the first inorganic semiconductor material is Si, Ge or a SiGe alloy, and the second semiconductor material is GaP, a GaAs x P 1-x  alloy, a GaAs x N y P 1-x-y  alloy, or WO 3 . 
     
     
         6 . The device according to  claim 1 , wherein the first inorganic semiconductor material is Si, and the second semiconductor material is GaP or a GaAs x N y P 1-x-y  alloy. 
     
     
         7 . The device according to  claim 1 , wherein the wires of the array have a length of greater than about 100 nm. 
     
     
         8 . A device for photoelectrochemical fuel generation, comprising:
 a first electrode comprising:
 a core comprising an array of wires, the wires comprising a first inorganic semiconductor material; and 
 a conformal coating on the array of wires of the core, the conformal coating comprising a second inorganic semiconductor material; 
   a second electrode; and   a membrane separating the first electrode and the second electrode.   
     
     
         9 . The device according to  claim 8 , wherein each of the first and second inorganic semiconductor materials is independently selected from the group consisting of Group IV elemental semiconductors, Group IV compound semiconductors, III-V semiconductors, and II-VI semiconductors. 
     
     
         10 . The device according to  claim 8 , wherein the first inorganic semiconductor material comprises Si, Ge, a SiGe alloy, GaP, a GaAs x P 1-x  alloy, a GaAs x N y P 1-x-y  alloy, or WO 3 . 
     
     
         11 . The device according to  claim 8 , wherein the second inorganic semiconductor material is different from the first inorganic semiconductor material and comprises GaP, a GaAs x P 1-x  alloy, a GaAs x N y P 1-x-y  alloy, or WO 3 . 
     
     
         12 . The device according to  claim 8 , wherein the first inorganic semiconductor material is Si, Ge or a SiGe alloy, and the second semiconductor material is GaP, a GaAs x P 1-x  alloy, a GaAs x N y P 1-x-y  alloy, or WO 3 . 
     
     
         13 . The substrate according to  claim 8 , wherein the first inorganic semiconductor material is Si, and the second semiconductor material is GaP. 
     
     
         14 . The device according to  claim 8 , wherein the wires of the array have a length of greater than about 100 nm. 
     
     
         15 . The device according to  claim 8 , wherein the second electrode comprises:
 a second core comprising a second array of wires, the wires of the second array of wires comprising a third inorganic semiconductor material; and   a second conformal coating on the second array of wires of the second core, the second conformal coating comprising a fourth inorganic semiconductor material.   
     
     
         16 . The device according to  claim 15 , wherein:
 the first electrode comprises a photoanode, the first inorganic semiconductor material of the first electrode comprises Si, and the second inorganic semiconductor material of the first electrode comprises n-type GaP; and   the second electrode is a photocathode, the third inorganic semiconductor material of the second electrode is Si, and the fourth inorganic semiconductor material of the second electrode comprises p-type GaP.   
     
     
         17 . The device according to  claim 8 , wherein the first electrode is a photocathode, and the second electrode is a photoanode comprising porous WO 3 . 
     
     
         18 . The device according to  claim 17 , wherein the porous WO 3  comprises an array of porous WO 3  wires. 
     
     
         19 . The device according to  claim 8 , wherein the first electrode is a photoanode, and the second electrode is a photocathode comprising an array of Si wires.