Solar Cells Having Nanowire Titanium Oxide and/or Silicon Carbide Cores and Graphene Exteriors

Abstract

An apparatus comprising a plurality of solar cells that each comprise a nanowire titanium oxide core having graphene disposed thereon. By one approach this plurality of solar cells can comprise, at least in part, a titanium foil having the plurality of solar cells disposed thereon wherein at least a majority of the solar cells are aligned substantially parallel to one another and substantially perpendicular to the titanium foil. Such a plurality of solar cells can be disposed between a source of light and another modality of solar energy conversion such that both the solar cells and the another modality of solar energy conversion generate electricity using a same source of light.

We claim: 
     
         1 . An apparatus comprising:
 a core consisting essentially of wide band-gap material, wherein the core comprises a longitudinal member;   a shell consisting essentially of graphene conformally disposed about at least a substantial portion of the core, the shell being partially transparent to sunlight.   
     
     
         2 . The apparatus of  claim 1  wherein the shell comprises at least a single layer of graphene. 
     
     
         3 . The apparatus of  claim 1  wherein the shell comprises no more than about ten layers of graphene. 
     
     
         4 . The apparatus of  claim 1  wherein the longitudinal member comprises a nanowire. 
     
     
         5 . The apparatus of  claim 4  wherein the nanowire consists of a cylindrically-shaped member. 
     
     
         6 . The apparatus of  claim 4  wherein the length of the nanowire is more than twenty times greater than a widest lateral cross-section thereof. 
     
     
         7 . The apparatus of  claim 6  wherein the lateral cross section is at least twenty nanometers. 
     
     
         8 . The apparatus of  claim 1  wherein the wide band-gap material comprises at least one of:
 boron; 
 iron; 
 titanium; 
 zinc; 
 carbon; and 
 silicon. 
 
     
     
         9 . The apparatus of  claim 8  wherein the wide band-gap material further comprises at least one of:
 a boride; 
 a carbide; 
 a nitride; 
 an oxide; and
 a sulfide. 
 
 
     
     
         10 . The apparatus of  claim 1  wherein the wide band-gap material comprises at least one of:
 a boride; 
 a carbide; 
 a nitride; 
 an oxide; and 
 a sulfide. 
 
     
     
         11 . The apparatus of  claim 1  wherein the apparatus comprises a plurality of the cores that each have one of the graphene shells disposed thereabout. 
     
     
         12 . The apparatus of  claim 10  wherein the plurality of cores are disposed with their longitudinal axes oriented substantially parallel to one another. 
     
     
         13 . The apparatus of  claim 11  wherein the longitudinal member has a length of at least 400 nanometers. 
     
     
         14 . The apparatus of  claim 12  wherein each of the cores comprises a nanowire having a radius of at least 20 nanometers. 
     
     
         15 . The apparatus of  claim 1  wherein the connection between a pathway connecting the shell and the core comprises a photovoltaic junction. 
     
     
         16 . The apparatus of  claim 1  wherein the core and the shell can include a dopant. 
     
     
         17 . A photovoltaic transducer comprising:
 a core consisting essentially of a wide band-gap material, wherein the core comprises a nanowire;   a shell consisting essentially of graphene conformally disposed about at least a substantial portion of the nanowire, the shell being partially transparent to sunlight;   wherein sunlight entering the nanowire and that is transmitted along the nanowire is at least mostly absorbed by the graphene notwithstanding the partial transparency of the shell.   
     
     
         18 . The photovoltaic transducer of  claim 17  wherein the graphene comprises at least a single monolayer of graphene. 
     
     
         19 . The photovoltaic transducer of  claim 18  wherein all of the sunlight that enters the nanowire and that is transmitted along the length of the nanowire is substantially absorbed by the graphene shell. 
     
     
         20 . The photovoltaic transducer of  claim 17  further comprising:
 a plurality of the nanowires disposed on a shared substrate, wherein each of the nanowires has one of the graphene shells conformally disposed thereabout. 
 
     
     
         21 . The photovoltaic transducer of  claim 20  wherein each of the nanowires comprising the plurality of the nanowires are disposed substantially perpendicular to the shared substrate.