The solar cell perovskite tandem/ topcon of Jinko
It was only in 2022 when the perovskite-silicon tandem photovoltaic technology exceeded for the first time 30% efficiency of converting light into electricity. Today, less than two years after that first great achievement, technology continues to race towards new world records, aiming to get as close as possible to the new theoretical limit. That’s 43% efficiency. The latest progress in this direction comes from JinkoSolar, a Chinese photovoltaic company that has created a record-breaking perovskite/topcon tandem solar cell.
The photovoltaic tandem perovskite/ silicon
Introduced for the first time in 2013, tandem photovoltaic perovskite/ silicon appeared immediately as one of the most interesting approaches to increase solar yield without the use of concentrators. And maintaining cost-effective production. The idea is to combine semiconductors with different band gaps in a single device, to expand the portion of exploitable solar spectrum. In this case silicon can efficiently use low-energy photons, while perovskites can be tuned to absorb the higher frequency end of the spectrum.
In this context most of the efforts of the academic world have focused on two-terminal monolithic tandems, in which the perovskite subcellum is manufactured directly on a silicon solar cell, connected in series by an internal junction. An approach that offers a smaller number of phases of working of the materials regarding the alternative “mechanics“. In fact, tandem photovoltaics can also be realized by physically stacking a semi-transparent perovskite cell on a silicon cell. The advantage? Integration is simpler and the sub-modules work independently.
Perovskite/Si, the record of efficiency
In fact, for this segment the highest value ever reached in terms of conversion of light into electricity is up to Longi that in November 2023 obtained an efficiency of 33.9%. But an acknowledgement goes undeniably also to Jinko solar since its is the first perovskite/ silicon tandem solar cell with N-type topcon technology to have achieved a conversion efficiency of 33.34%.
Monocrystalline silicon solar cell, new record for JinkoSolar
One of the advantages of this progress is the use of proven technology such as topcon, an acronym for Tunnelling Oxide Passivated Contact. The TOPcon cell has a fully passivated back, contacts included, by adding a thin layer of silicon oxide. This element creates a tunnel junction that allows better transport and collection of electrons, while reducing the recombination speed. topcon photovoltaic modules therefore work well even in low light conditions.
Jinko’s perovskite tandem solar cell employs a high efficiency n-type monocrystalline topcon unit as the lower cell. Through various materials and technological innovations, including ultra-thin polycrystalline silicon passivated contact technology, a new light trapping technology, an intermediate recombination layer with high light transmission and high mobility of carriers, the company has advanced its performance towards a new category record.
The tandem perovskite/topcon solar cell represents for the company “the determination to continuously explore the limits and the strong capacity for technological innovation“. “In addition – comments Jin Hao, CTO of JinkoSolar – lays a solid technical foundation for the subsequent development of the company”.