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. - 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. <EOS>