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.