Solar cell comprising a metal-oxide buffer layer and method of fabrication

Abstract

A perovskite-based solar cell comprising a transparent electrode disposed on a buffer layer that protects the perovskite from damage during the deposition of the electrode is disclosed. The buffer material is deposited using either low-temperature atomic-layer deposition, chemical-vapor deposition, or pulsed chemical-vapor deposition. In some embodiments, the perovskite material is operative as an absorption layer in a multi-cell solar-cell structure. In some embodiments, the perovskite material is operative as an absorption layer in a single-junction solar cell structure.

1 . A solar cell ( 100 ) that is operative for converting a first light signal ( 124 ) into electrical energy, the solar cell including:
 a first absorption layer ( 110 ) comprising a first material ( 112 ), the first material being a perovskite and having a first energy bandgap;   an electrical contact ( 122 ) that is in electrical communication with the first absorption layer, the electrical contact being substantially transparent for a first wavelength range, the first light signal including light within the first wavelength range; and   a buffer layer ( 116 ) that is between the electrical contact and the first absorption layer, the buffer layer comprising a first layer ( 118 ) comprising a first metal oxide;   wherein the buffer layer is produced by a process selected from the group consisting of atomic-layer deposition (ALE), chemical-vapor deposition (CVD) and pulsed-chemical-vapor deposition (p-CVD), and wherein the buffer layer is formed at a temperature that is less than or equal to 150° C.   
     
     
         2 . The solar cell of  claim 1  wherein the first metal oxide is tin oxide. 
     
     
         3 . The solar cell of  claim 1  wherein the first metal oxide is selected from the group consisting of zinc oxide, zinc tin oxide, titanium oxide, nickel oxide, platinum oxide, tungsten oxide, and vanadium oxide. 
     
     
         4 . The solar cell of  claim 1  wherein the buffer layer further includes a second layer ( 120 ) comprising a second metal oxide. 
     
     
         5 . The solar cell of  claim 4  wherein first metal oxide is tin oxide and the second metal oxide is zinc tin oxide. 
     
     
         6 . The solar cell of  claim 1  wherein the buffer layer is operative for extracting electrons from the first absorption layer. 
     
     
         7 . The solar cell of  claim 1  wherein the buffer layer is substantially non-reactive with halides. 
     
     
         8 . The solar cell of  claim 1  wherein the buffer layer is substantially conformal with a first surface (S 1 ) of the first absorption layer. 
     
     
         9 . The solar cell of  claim 1  wherein the first material comprises cesium. 
     
     
         10 . The solar cell of  claim 1  further comprising a second absorption layer ( 602 ) comprising a second material ( 630 ) having a second energy bandgap that is lower than the first energy bandgap, wherein the first absorption layer and second absorption layer are monolithically integrated and collectively define a monolithically integrated tandem solar cell ( 600 ). 
     
     
         11 . The solar cell of  claim 10  wherein the second material is selected from the group consisting of silicon, gallium arsenide (GaAs), cadmium telluride (CdTe), copper indium gallium selenide (CIGS), and perovskites. 
     
     
         12 . The solar cell of  claim 10  wherein the first material comprises cesium and the second material is silicon. 
     
     
         13 - 20 . (canceled) 
     
     
         21 . A solar cell ( 100 ) that is operative for converting a first light signal ( 124 ) into electrical energy, the solar cell including:
 a first absorption layer ( 110 ) comprising a first material ( 112 ), the first material being a perovskite and having a first energy bandgap;   an electrical contact ( 122 ) that is in electrical communication with the first absorption layer, the electrical contact being substantially transparent for a first wavelength range, the first light signal including light within the first wavelength range; and   a buffer layer ( 116 ) that is between the electrical contact and the first absorption layer, wherein the buffer layer consists of metal oxide.   
     
     
         22 . The solar cell of  claim 21  wherein the buffer layer includes a first metal oxide that is selected from the group consisting of tin oxide, zinc oxide, zinc tin oxide, titanium oxide, nickel oxide, platinum oxide, tungsten oxide, and vanadium oxide. 
     
     
         23 . The solar cell of  claim 21  wherein buffer layer includes a first layer ( 118 ) comprising a first metal oxide. 
     
     
         24 . The solar cell of  claim 23  wherein the buffer layer includes a second layer ( 120 ) comprising a second metal oxide. 
     
     
         25 . The solar cell of  claim 24  wherein the first metal oxide is tin oxide and the second metal oxide is zinc tin oxide. 
     
     
         26 . The solar cell of  claim 21  wherein the buffer layer is operative for extracting electrons from the first absorption layer. 
     
     
         27 . The solar cell of  claim 21  wherein the buffer layer is substantially non-reactive with halides. 
     
     
         28 . The solar cell of  claim 21  wherein the buffer layer is substantially conformal with a first surface (S 1 ) of the first absorption layer. 
     
     
         29 . The solar cell of  claim 21  wherein the first material comprises cesium. 
     
     
         30 . The solar cell of  claim 21  further comprising a second absorption layer ( 602 ) comprising a second material ( 630 ) having a second energy bandgap that is lower than the first energy bandgap, wherein the first absorption layer and second absorption layer are monolithically integrated and collectively define a monolithically integrated tandem solar cell ( 600 ). 
     
     
         31 . The solar cell of  claim 30  wherein the second material is selected from the group consisting of silicon, gallium arsenide (GaAs), cadmium telluride (CdTe), copper indium gallium selenide (CIGS), and perovskites. 
     
     
         32 . The solar cell of  claim 30  wherein the first material comprises cesium and the second material is silicon.