Solar element with increased efficiency and method for increasing efficiency

A solar element having at least one solar cell which has a band gap frequency vBG,

• at least one luminescent element which absorbs electromagnetic radiation with frequencies between two frequencies vLE1 and vLE2≧vLE1 and emits electromagnetic radiation with at least a frequency vLE3,
• at least one upconverter which absorbs electromagnetic radiation with frequencies between two frequencies vHK1 and vHK2≧VHK1 and emits radiation with at least a frequency vHK3, and also
• a first selectively reflecting structure which reflects a part of the incident electromagnetic radiation and transmits a part of the incident radiation,
• wherein vLE1 is smaller than vBG,
• there applies for at least one of the at least one frequencies VLE3, VHK1≦VLE3≦VHK2, and
• there applies for at least one of the at least one frequencies vHK3, vHK3≧VBG,
• wherein the at least one luminescent element is disposed adjacent to respectively the first selectively reflecting structure and the first selectively reflecting structure is disposed adjacent to respectively at least one of the at least one upconverters and the at least one upconverter is disposed adjacent to the solar cell, and
• wherein the at least one luminescent element has a top surface having a total surface area that faces the solar cell and the at least one upconverter has a top surface having a total surface area that faces the solar cell and wherein the portion of the total surface area of the top surface of the at least one luminescent element that faces the solar cell is greater than the total surface area of the top surface of the at least one upconverter that faces the solar cell.