Photo-voltaic element and method of manufacturing the same

Abstract

A photo-voltaic element (1) comprising a stack of layers is provided. The stack of layers at least includes the following layers arranged in the order named: a first electrode layer, a first charge carrier transport layer, an insulating layer, a second electrode layer, a second charge carrier transport layer, and a photo-electric conversion layer. The photo-electric conversion layer (70), comprises a plurality of distributed extensions (72) extending through the second charge carrier transport layer (60), the second electrode layer (50) and the insulating layer (40) to the first charge carrier transport layer (30). The extensions (72) have an effective cross-section Deff in the range of 0.5 to 10 micron, and have an average pitch in the range of 1.1 to 5 times said effective cross-section.

1 . A photo-voltaic element comprising a stack of layers, the stack of layers at least including the following layers arranged in the order named:
 a first electrode layer for receiving charge carriers of a first polarity,   a first charge carrier transport layer, for transport of charge carriers having said first polarity,   an insulating layer,   a second electrode layer for receiving charge carriers of a second polarity opposite to said first polarity,   a second charge carrier transport layer, for transport of charge carriers having said second polarity,   a photo-electric conversion layer, wherein charge carriers of the first polarity have a first mobility and wherein charge carriers of the second polarity have a second mobility, the photo-electric conversion layer comprising a plurality of distributed extensions extending through said second charge carrier transport layer, said second electrode layer and said insulating layer to the first charge carrier transport layer, the extensions having an effective cross-section D eff  in the range of 0.5 to 10 micron, and having an average pitch in the range of 1.1 to 5 times said effective cross-section, the effective cross-section being a diameter of a circle having an area corresponding to the cross-sectional area A Ø  of the extensions, and the extensions having a circumference O that is less than 10 times the effective diameter D eff , a contact-surface of the photo-electric conversion layer with the first charge carrier transport layer having a first surface area, and a contact-surface of the photo-electric conversion layer with the second charge carrier transport layer having a second surface area, a ratio between the second surface area and the first surface area being approximately equal to a ratio between the first mobility and the second mobility.   
     
     
         2 . The photo-voltaic element according to  claim 1 , wherein said second electrode layer has anodized edge surfaces facing the extensions of the photo-electric conversion layer. 
     
     
         3 . The photo-voltaic element according to  claim 1 , wherein an insulating material is provided around said extensions, forming an insulating wall between said second electrode layer and said photo-electric conversion layer. 
     
     
         4 . The photo-voltaic element according to  claim 1 , further comprising a growth layer at an interface between said photo-electric conversion layer and said second charge carrier transport layer as well as at an interface between said extensions of the photo-electric conversion layer and each of edge surfaces of said second charge carrier transport layer, said second electrode layer and said insulating layer and at an interface between said extensions of the photo-electric conversion layer and the first charge carrier transport layer. 
     
     
         5 . The photo-voltaic element according to  claim 1 , wherein the photo-electric conversion layer is provided of a perovskite material. 
     
     
         6 . The photo-voltaic element according to  claim 1 , wherein the photo-electric conversion layer is made of copper indium gallium selenide (CIGS). 
     
     
         7 . The photo-voltaic element according to  claim 1 , wherein an edge portion of an upper surface of the first electrode layer is kept free from material of the first charge carrier transport layer and is provided with a first electrical contact and or an edge portion of an upper surface of the second electrode layer is kept free from material of the second charge carrier transport layer and is provided with a second electrical contact. 
     
     
         8 . The photo-voltaic element according to  claim 1 , wherein said first electrode layer, said first charge carrier transport layer, said insulating layer and said second electrode layer are provided as a plurality of layer segments, wherein a plurality of lateral sub-stack segments each comprise a respective first electrode layer segment, a first charge carrier transport layer segment, an insulating layer segment and a second electrode layer segment, wherein a second electrode layer segment of a lateral sub-stack segment extends over a first electrode layer segment n a neighboring sub-stack segment, therewith forming an electrical connection between said second electrode layer segment of said lateral sub-stack segment and said first electrode layer segment in said neighboring lateral sub-stack segment. 
     
     
         9 . The photo-voltaic element according to  claim 1 , wherein the extensions taper outward in a direction from the first charge carrier transport layer towards the second charge carrier layer. 
     
     
         10 . The photo-voltaic element according to  claim 9 , wherein a material of the second charge carrier transport layer covers a surface of the second electrode surrounding the extensions. 
     
     
         11 . The photo-electric element according to  claim 1 , wherein the first charge carrier layer is absent in areas of the first electrode layer covered by the insulating layer. 
     
     
         12 . Method of manufacturing a photo-voltaic element comprising the steps of:
 providing a substrate;   depositing thereon a stack of layers comprising at least in the order named:   a first electrode layer for receiving charge carriers of a first polarity;   a first charge carrier transport layer, for transport of charge carriers having said first polarity;   an insulating layer;   a second charge carrier transport layer, for transport of charge carriers having a second polarity opposite to said first polarity;   a second electrode layer for receiving charge carriers of the second polarity;   wherein the insulating layer and layers subsequently deposited in this step form a substack having an upper surface,   applying a resist layer on said upper surface, wherein said resist layer is provided with a plurality of distributed openings towards said upper surface, the openings having an effective cross-section D in the range of 0.5 to 10 micron, and having an average pitch in the range of 1.1 to 5 times said effective cross-section, the effective cross-section being a diameter of a circle having an area corresponding to the cross-sectional area A Ø  of the extensions, and the extensions having a circumference O that is less than 10 times the effective diameter D eff ,   etching to selectively remove material of the sub-stack facing the openings,   removing the resist layer subsequent to said etching,   depositing and curing a photo-electric conversion layer subsequent to said removing
 wherein a contact-surface of the photo-electric conversion layer with the first charge carrier transport layer has a first surface area, and a contact-surface of the photo-electric conversion layer with the second charge carrier transport layer has a second surface area, and a ratio between the second surface area and the first surface area is approximately equal to a ratio between a first mobility of the charge carriers having said first polarity and a second mobility of the charge carriers having said second polarity. 
   
     
     
         13 - 14 . (canceled) 
     
     
         15 . The method according to  claim 12 , wherein the second charge carrier transport layer is deposited with an electroplating process and subsequent to removing the resist layer, and preceding depositing and curing a photo-electric conversion layer. 
     
     
         16 . The method according to  claim 12 , wherein the first charge carrier transport layer is deposited with an electroplating process. 
     
     
         17 . The method according to  claim 12 , further comprising anodizing an edge surface of the second electrode layer resulting from said etching, said anodizing being performed prior to the step of depositing the photo-electric conversion layer. 
     
     
         18 . The method according to  claim 12 , further comprising conformally depositing a layer of an insulating material subsequent to said step of etching and anisotropically etching said layer to removes the insulating material from the surface of the second charge carrier transport layer and from the surface portions of the first charge carrier transport layer within the openings while keeping a layer of the insulating material on the walls of the openings intact. 
     
     
         19 . The method according to  claim 12 , further comprising depositing a growth layer subsequent to said step of etching and prior to the step of depositing the photo-electric conversion layer. 
     
     
         20 . The method according to  claim 12 , further comprising depositing a barrier over said photo-electric conversion layer. 
     
     
         21 . (canceled) 
     
     
         22 . The method according to  claim 20 , comprising applying a light in coupling structure over said barrier. 
     
     
         23 . (canceled) 
     
     
         24 . The method according to  claim 12 , wherein the photo-electric conversion layer is provided of a perovskite material or of copper indium gallium selenide (CIGS).