Tandem - Page 2

China-based global PV and ESS supplier, Jinko Solar, has announced a significant breakthrough in the development of its N-type TOPCon-based perovskite tandem solar cell.

Tested by the Shanghai Institute of Microsystem and Information Technology, the cell reportedly achieved an impressive conversion efficiency of 33.24%. This enhancement surpasses JinkoSolar's previous record of 32.33% for the same type of tandem cells.

Researchers at China's Qingdao University of Science and Technology and Canada's University of Toronto have developed a thermal regulation strategy by incorporating carboranes into perovskites to improve the performance of inverted tin-lead perovskite tech for all-perovskite tandem solar cells. 

The Chinese-Canadian research group has designed a monolithic all-perovskite tandem solar cell that utilizes a top inverted perovskite PV device based on an absorber made with mixed tin-lead (Sn-Pb) perovskite via the newly developed thermal regulation strategy.

Researchers from the University of Science and Technology of China and Hefei University of Technology have developed a proof-of-concept tandem solar cell tandem solar cell by using antimony selenide (Sb₂Se₃) for the bottom cell and a wide-bandgap organic-inorganic hybrid perovskite material for the top cell. The device reached a power conversion efficiency of more than 20%, which demonstrates that antimony selenide has a high potential for bottom-cell applications.

Antimony selenide (Sb₂Se₃) possesses a band gap of 1.05–1.2 eV and has been widely applied in single-junction solar cells. Based on its band gap, Sb₂Se₃ can also be used as the bottom cell absorber material in tandem solar cells. Sb₂Se₃-based solar cells also exhibit excellent stability with nontoxic compositional elements. In this recent work, the team demonstrated a perovskite/antimony selenide four-terminal tandem solar cell with a specially designed and fabricated transparent electrode for an optimized spectral response.

Researchers at the University of Toledo have designed a four-terminal (4T) tandem solar cell with a top device that uses a perovskite absorber with a tunable wide-bandgap and a bottom cell based on a commercially established narrow-bandgap absorber technology made of cadmium telluride (CdTe).

Perovskite-cadmium telluride tandem solar cells are relatively unexplored compared to other tandems. While the efficiency potential of CdTe-based tandems is lower than CIGS-based tandems due to the higher bandgap of the CdTe bottom cell, the broader commercial success of CdTe solar cells makes them interesting to investigate for thin-film tandem applications.

As part of the Investing in America agenda, the U.S. Department of Energy (DOE) recently announced a $71 million investment in research, development, and demonstration projects to grow the network of domestic manufacturers across the U.S. solar energy supply chain. 

The selected projects will address gaps in the domestic solar manufacturing capacity for supply chain including equipment, silicon ingots and wafers, and both silicon and thin-film solar cell manufacturing. The projects will also open new markets for solar technologies such as dual-use photovoltaic (PV) applications, including building-integrated PV and agrivoltaics. 

Researchers from EPFL, CSEM and Empa have demonstrated a cell design combining additive and substrate engineering that yields consistently high power conversion efficiencies and discussed various design aspects that are important for reproducibility and performance. 

The team presented two key developments with a synergetic effect that boost the PCEs of tandem devices with front-side flat Si wafers—the use of 2,3,4,5,6-pentafluorobenzylphosphonic acid (pFBPA) in the perovskite precursor ink that suppresses recombination near the perovskite/C60 interface and the use of SiO₂ nanoparticles under the perovskite film that suppress the enhanced number of pinholes and shunts introduced by pFBPA, while also allowing reliable use of Me-4PACz as a hole transport layer. 

Researchers from Soochow University, Hunan University and Friedrich-Alexander University Erlangen-Nürnberg have incorporated pseudo-halogen thiocyanate (SCN) ions in iodide/bromide mixed halide perovskites and showed that they enhance crystallization and reduce grain boundaries. 

While perovskite/organic tandem solar cells could theoretically achieve high efficiency and stability, their performance is hindered by a process known as phase segregation, which degrades the performance of wide-bandgap perovskite cells and adversely affects recombination processes at the tandem solar cells' interconnecting layer. The team devised a strategy to suppress phase segregation in wide-bandgap perovskites, thus boosting the performance and stability of perovskite/organic tandem cells. This strategy entails the use of a pseudo-triple-halide alloy incorporated in mixed halide perovskites based on iodine and bromine.

Researchers from China's Wuhan University and South China Normal University have developed a two-terminal (2T) monolithic all-perovskite tandem solar cell that uses a tin-lead (Sn-Pb) perovskite material for the top cell.

The team explained that mixed Sn-Pb perovskites have a narrow bandgap (NBG) of approximately 1.26 eV, which makes them ideal for efficient light harvesting and current-matching with wide bandgap (WBG) subcells in all-perovskite tandem cells.

Researchers at the University of Sydney, Microsolar, University of New South Wales and MiaSolé Hi-Tech Corp. have reported a monolithic perovskite–CIGS tandem solar cell on a flexible conductive steel substrate with an efficiency of 18.1%, the highest for a flexible perovskite–CIGS tandem to date, representing an important step toward flexible perovskite-based tandem photovoltaics.

The advantage of the flexible and conductive steel substrate is that the steel itself can act as both a substrate and an electrode for either large-area-monolithic-panel or smaller-area-singular single-junction or multi-junction cell fabrication.

Researchers at the University of Potsdam, Humboldt-University of Berlin, University of Wuppertal, Swansea University, University of Oxford, East China University of Science and Technology, Friedrich-Alexander-University Erlangen-Nürnberg and HZB have shown that ion-induced field screening is a dominant factor in the operational stability of perovskite solar cells (PSCS). 

The rather poor perovskite stability is usually attributed to electronic defects, electrode oxidation, the ionic nature of the perovskite, or chemical decomposition under moisture and oxygen. Understanding the underlying degradation mechanism is crucial to enable targeted improvements. "In our article, we demonstrate that an increasing concentration of defects in the cells is apparently not a decisive factor for degradation," says Martin Stolterfoht, former leader of the Heisenberg junior research group PotsdamPero at the University of Potsdam and now professor at the Chinese University of Hong Kong.