Tandem

TandemPV has announced it has secured $50 million in Series A funding and debt, led by Eclipse, with participation from Constellation Energy, Planetary Technologies, Uncorrelated Ventures, Trellis Climate, Tom Werner (former CEO of SunPower), Stifel Bank, CSC Leasing, and other existing and new investors. This investment will enable TandemPV to construct a commercial-scale manufacturing facility in the U.S., accelerating the adoption of its high-efficiency solar panels and allowing the U.S. to reduce its dependency on foreign manufacturers while increasing its energy security.

According to the statement, TandemPV's tandem perovskite panels currently achieve 28% efficiency and are projected to surpass 30% by late 2025, proving to be 30% more powerful than the average silicon solar panel. Tandem PV's panels lower labor and land costs, offering customers a lower total cost of ownership and a sustainable path toward decarbonization.

Researchers from the Indian Institute of Technology Roorkee, CSIR-National Physical Laboratory and Academy of Scientific and Innovative Research (AcSIR) have designed a solution-based fabrication approach involving a high-performance semi-transparent perovskite cell (ST-PSC) stacked in tandem with a hybrid heterojunction silicon solar cell (HHSC). 

The hybrid heterojunction solar cell was embedded as a bottom device in a four-terminal perovskite-silicon solar cell using the new solution processing technique. The novel cell architecture, according to the team, could be produced at significantly lower costs compared to conventional perovskite-silicon tandem designs.

Researchers from Fraunhofer ISE and King Abdullah University of Science and Technology (KAUST) have designed a perovskite-silicon tandem solar cell that is said to offer improved reproducibility. The device uses self-assembled monolayers (SAMs) that reportedly result in low parasitic absorption and rapid charge extraction.

Schematic of the fully-textured perovskite/silicon tandem solar cell structure studied. Image from: small methods

SAMs have shown great potential as hole-selective contacts for high-efficiency PSCs due to their easy processing, passivation capability, and low parasitic absorption. However, for the deposition of SAMs with a monolayer thickness and a high packing density on metal oxide substrates, critical challenges persist. To address these, the study focuses on the impact of annealing temperature – an intrinsic yet so far unexplored process parameter – during the formation of SAMs.

Recently, a University of Louisville team of researchers used nanoparticle inks by Sofab Inks (a U of Louisville spinout) to create PSCs with ~20% PCE on flexible substrates. Their study addresses the solvent scope and perovskite compatibility of acetate-stabilized yttrium-doped SnO₂ (Y:SnO₂) dispersions.

Tin oxide (SnO₂) stands out as a compelling electron transport material (ETM) for perovskite solar cells (PSCs), boasting exceptional optoelectronic properties, coupled with low-temperature solution processability, cost-effectiveness, and remarkable stability. However, the widespread application of SnO₂ has been hindered by solvent incompatibilities, limiting its use to devices where it is deposited beneath the perovskite layer. To unlock the full potential of SnO₂ and expand its use across various device structures, including inverted PSCs and tandem devices, innovative deposition strategies will need to be developed. These advancements could pave the way for more efficient and versatile solar cell designs, pushing the field of photovoltaics forward.

The scientists showed that dispersions in several lower alcohols and select polar aprotic solvents can be directly deposited on perovskite using scalable and low-temperature processes. In addition, they are compatible with various perovskite formulations, including those with mixed cations and mixed anions.

It was reported that China-based Risen Energy, a company primarily focused on grid-connected PV power generation systems, announced its new achievement in the research and development of perovskite and HJT tandem solar cells. A power conversion efficiency of 30.99% was reportedly achieved by Risen Energy’s R&D institution, and the result was confirmed by the China National Center of Supervision and Inspection on Solar Photovoltaic Products Quality (CPVT).

As a leading solar module manufacturer in China, Risen Energy believes that HJT solar cells with unique structure and features are promising products among p-type and n-type single junction solar cells. HJT’s advantages are significant in perovskite and silicon tandem solar cells, making it naturally suitable as a base for tandem cells. HJT is seen as one of the best bottom cells for crystalline silicon and perovskite tandem cells. Other types of crystalline silicon cells, due to the lack of ITO film, require redesign of the structure prior to tandem processing, which increases cost and complexity.

India-based P3C has announced a partnership with the National Institute of Solar Energy (NISE). 

P3C and NISE have signed a Memorandum of Understanding (MoU) to accelerate India’s transition to a low-carbon, sustainable future. This partnership will focus on advancing perovskite solar technology and powering next-generation solar solutions, including glass and flexible perovskite modules, tandem solar cells, and advanced PV innovations for both urban and rural environments. The two parties' shared goal is to make clean energy accessible, efficient, and scalable across India, from rooftops and farmlands to smart cities and remote villages.

Researchers from China's Westlake University, Advanced Solar Technology Institute of Xuancheng and Turkey's Marmara University have addressed the stability issues of perovskite solar cells (PSCs) by developing a divalent cation replacement strategy that mitigates ionic migration while limiting phase segregation. 

Using the new method, the scientists fabricated a champion cell that showed a PCE of 23.20% (certified 22.71%) for a single-junction PSC with a bandgap between 1.67 eV and 1.68 eV. Furthermore, a PCE of 30.13% was obtained for mechanically stacked perovskite/Cu(In,Ga)Se₂ tandem devices, and a PCE of 21.88% for transparent perovskite devices. Finally, they obtained a steady-state PCE of 23.28% (certified 22.79%) for flexible monolithic perovskite/Cu(In,Ga)Se₂ tandem cells.

ART-PV India, an IIT Bombay-incubated start-up, has been awarded a $10 million grant by the Ministry of New and Renewable Energy (MNRE). The funding will enable the company to set up a manufacturing plant for high-efficiency tandem solar cells.

ART-PV has developed a 4T cell with PCE >30% on small area ~1 cm², which will be transferred to 2T using industry partners supplying semi-processed bottom sub-cells.

Scientists from HZB and Humboldt University Berlin have reported a CIGS-perovskite tandem cell that sets a record with an efficiency of 24.6%, certified by the independent Fraunhofer Institute for Solar Energy Systems.

The team's new tandem solar cell combines a bottom cell made of CIGS with a top cell based on perovskite. By improving the contact layers between the top and bottom cells, they were able to increase the efficiency to 24.6%. This cell was the result of a successful team effort: the top cell was fabricated by TU Berlin master's student Thede Mehlhop under the supervision of Stefan Gall. The perovskite absorber layer was produced in the joint laboratory of HZB and Humboldt University of Berlin. The CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. He also used the high-performance cluster system KOALA, which enables the deposition of perovskites and contact layers in vacuum at HZB.

Researchers from China's Northwest Normal University, Xidian University and Xi'an Shiyou University have developed a four-terminal perovskite-CIGS tandem solar cell based on a top semi-transparent perovskite device with an efficiency of 21.26% and a high bifaciality factor of 92.2%. The scientists used a solvent-annealing strategy to produce a perovskite film with full coverage, larger grains, superior crystallinity and free of detectable lead iodide impurity.

The team fabricated a four-terminal (4T) tandem solar cell based on a top semi-transparent perovskite device and a bottom cell relying on copper-indium-gallium-selenide (CIGS). The scientists used a stepwise dimethyl sulfoxide (DMSO) solvent-annealing method to improve the crystallinity of the perovskite film used in the perovskite top cell and fabricated films with a wide bandgap of 1.68 eV via two consecutive heating steps: annealing at 100 C and then 80 C.