Tandem - Page 17

Perovskite solar panels have been under intensive R&D, and it seems as if commercial production is right around the corner. Some pilot-scale production lines are already functional, and companies are now ramping up production of perovskite panels, using various technologies.

UK-based Oxford PV, for example, recently announced that it has completed the build-out of its 100 MW manufacturing site in Germany, and it is on track to start full production in 2022. China's Microquanta Semiconductor perovskite panel factory is reportedly also nearing production (which should have started late 2020, but updates have not been available since), and another China-based company, GCL, has raised around $15 million USD to expand its pilot-scale production factory to mass production (100 MW).

Scientists from China's Nanjing University and Chinese Academy of Sciences have found that a change to the hole transport layer material helped reduce voltage loss in a perovskite solar cell. The discovery demonstrates a promising new way to overcome a major challenge for perovskites ' particularly those used as the top layer in a tandem device.

The group of scientists noticed that a large part of the problematic voltage loss occurs at the interface between the active perovskite and the hole transport layer (HTL) that helps to carry a charge out of the device, and decided to experiment with alternate materials to try and limit this issue.

Researchers from the Australian National University and the University of New South Wales (UNSW) recently used perovskite solar cells for the development of a novel technology for direct solar hydrogen generation (DSTH), claimed to achieve an impressive solar-to-hydrogen efficiency of around 20%.

In DSTH systems, the electricity generated by a PV unit is used to directly drive water-splitting redox reactions without the need for an electrolyzer or complex power infrastructure. Commercial viability, however, remains unattainable despite efficiencies close to 19%, due to the use of expensive semiconductors and noble-metal catalysts.

Scientists from Oxford PV have recently published a study describing how pairing metal halide perovskites with conventional silicon leads to a more powerful solar cell that overcomes the 26% practical efficiency limit of using silicon cells alone.

'We identified perovskites as the perfect partner for a tandem system with silicon,' commented author Laura Miranda Pérez.

Researchers from Korea and Vietnam have developed and designed a bifacial four-terminal perovskite/crystalline silicon heterojunction tandem solar cell configuration albedo reflection in which the c-Si HJ bottom sub-cell absorbs the solar spectrum from both the front and rear sides (reflected light from the background such as green grass, white sand, red brick, roofing shingle, snow, etc.).

This approach reportedly achieved an outstanding conversion efficiency exceeding 30%, higher than those of both the top and bottom sub-cells. Notably, this efficiency is also greater than the Schockley'Quiesser limit of the c-Si solar cell (approximately 29.43%). The proposed approach has the potential to lower industrial solar cell production costs in the near future.

Philipp Tockhorn from Helmholtz-Zentrum Berlin (HZB) recently presented his team's work at the virtual OSA Advanced Photonics Congress (July 26th to 30th, 2021). In this new work, the researchers used simulation and experiments to illustrate that introducing a small nanoscale texturing on the surface of materials in perovskite or silicon tandem solar cells can raise the efficiency above 29%, by decreasing the amount of light energy lost by reflection.

The researchers presented nanotextured perovskite/silicon tandem solar cells that are on par with the best cells presented to date. These findings may contribute to the further development of highly efficient perovskite/silicon tandem solar cells and have the potential to further decrease the cost of solar electricity.

Earlier this month, Oxford PV announced the completion of the build-out of its manufacturing site in Brandenburg an der Havel, Germany. Oxford PV concluded that announcement by saying that "With the achievement of this factory milestone, Oxford PV has terminated its exclusive relationship with Meyer Burger".

Meyer Burger Technology was informed of the termination of partnership (in place since 2019) through the press release (as well as a letter from Oxford Photovoltaics). In view of the unexpected announcement of termination by Oxford PV, Meyer Burger is reportedly considering legal options to enforce its rights.

GCL Optoelectronic Materials and SC-Solar have signed a strategic cooperation agreement to jointly develop and promote tandem perovskite solar cells.

Under the agreement, both companies will be working closely together to develop the equipment and production line for tandem perovskite cells. They will share resources and find ways to complement each other's strengths with respect to process technology and fabrication equipment. GCL Optoelectronic Materials is a subsidiary of vertically integrated solar enterprise GCL. SC-Solar is a subsidiary of J.S. Machine, which develops packaging and manufacturing solutions for many industries.

Scientists from Pennsylvania State University, Shaanxi Normal University, Hubei University and the US Army Combat Capabilities Development Command have designed a semi-transparent perovskite solar cell that reached 19.8%, and 28.3% in a tandem cell stacked on top of a silicon-heterojunction device. The device is based on a film of gold just a few atoms thick, grown using an innovative seeding method, which is both highly conductive and transparent.

The team investigated, in their new study, a new method to grow a very thin, continuous layer of gold onto a perovskite solar cell as the top electrode layer. Despite the fact that gold is a rare and expensive material, the group is convinced its approach offers an alternate, efficient route to fabricating perovskite and tandem solar cells.

The following is a sponsored post by TCI

Tokyo Chemical Industry Company Limited (TCI) is now offering new hole selective self-assembled monolayer (SAM) forming agents, 2PACz [C3663], MeO-2PACz [D5798] and Me-4PACz [M3359] for high performance perovskite solar cells and OPVs.

The new materials enable efficient, versatile and stable p-i-n perovskite solar cell devices. These materials are useful for tandem solar cells as they grant conformal coverage on rough textures. In fact, a perovskite solar cell that uses the SAM hole transport layer can realize more than 20% efficiency without using dopants or additives. Perovskite-Silicon tandem solar cells that use Me-4PACz as a hole contact material realized 29.15% efficiency. Costs are lowered thanks to extremely low material consumption, and the processing is very simple and scalable.