Quantum photovoltaics: lequantum dot solar cellsrepresent an emerging research sector in the field ofphotovoltaic. This technology aims to employ iquantum dotsas a photovoltaic material to replace the raw materials currently used such as silicon and CIGS (characteristic of thin-film photovoltaics) or thecadmium telluride.
Quantum photovoltaics, the basic principle
In quantum photovoltaics, the conversion of light radiation into energy takes place by means of semiconductors of the order of the nanometer (one billionth of a meter), known as quantum dots in colloidal solution.
Research on thequantum photovoltaicsare focused on the so-called "band gap": this technology uses iquantum dotstunable in a wide range of energy levels that change the size of the quantum dot. Inphotovoltaicconventional, theband gapis already prefixed by the materials used while in thequantum photovoltaicsthe speech changes. The band gap makes thequantum dotsattractive for the creation of new onesPhotovoltaic cellsmulti-junction, that is, that exploit a large "range of energy levels" so as to be able to extract a greater amount of electricity from the spectrum of the sun's light radiation.
The first models ofquantum photovoltaicsthey have been produced with very expensive epitaxy processes, currently cheaper manufacturing models have been developed which exploit the so-called “wet chemistry”. These experimental methods aim at the synthesis of quantum dots using the wet chemistry of colloidal quantum dots so as to have the possibility of producing quantum dots in the form of a solution.
We get to talk about colloidal solar cells(CQD,colloidal quantum dots), who hold the record ofefficiency for photovoltaicsquantum dots.
Despite the great potential of thequantum photovoltaics, currently, while considering the most advancedcolloidal solar cells, the efficiency is just 5.1%, very low if we consider that that ofsiliconcommercial crude is about 17%. In theory, the efficiency of thequantum photovoltaicsit could reach or even exceed 60%, which is why new trials are needed.
The problems to be overcome are various, among these we mention the excessive heat produced in the quantum dots. One of the key factors in the operation of the quantum photovoltaicsit is the natural isolation of quantum dots from the surrounding material, a double-edged sword since this feature will cause it to reject a large amount of photons that will be reflected from the cell interface itself.