Tandem

Low-bandgap (LBG) mixed tin-lead (Sn−Pb) perovskite solar cells (PSCs) tend to suffer from inferior performance due to their high defect density. Conventionally, ethylenediammonium diiodide (EDADI) is used as a surface passivator to reduce defects and improve device photovoltaic performance, but it introduces severe hysteresis caused by excessive mobilized ions at the top interface.

Now, researchers from China's Soochow University and Sichuan University have reported a mobile ion suppressing strategy that uses hydrazine monohydrochloride (HM) as a bulk passivator to anchor the free ions in LBG perovskites. 

Chinese solar PV and energy storage company Trinasolar has announced a ‘new world record’ power conversion efficiency of 31.1% for its self-developed perovskite-crystalline silicon 2-terminal tandem solar cell.  

CalLab at Germany’s Fraunhofer Institute for Solar Energy has independently certified the claim, according to the manufacturer. Trinasolar says this is the 1^st time that the cell efficiency for a large-area industrial-grade cell size has exceeded 31%.  

Researchers at the Korea Institute of Energy Research, Gyeongsang National University, University of Science and Technology (UST), Korea Institute of Science and Technology (KIST), Korea Institute of Energy Technology (KENTECH) and Yonsei University have developed lightweight flexible perovskite/CIGS tandem solar cells and achieved a power conversion efficiency of 23.64%, which they claim is the highest efficiency achieved in flexible perovskite/CIGS tandem solar cells to date. 

Image from: Joule

The solar cells developed by the research team are extremely lightweight and can be attached to curved surfaces, making it a promising candidate for future applications in buildings, vehicles, aircraft, and more.

Oxford PV has signed a patent licensing agreement with Chinese module manufacturer Trina Solar, that covers the manufacture and sale of perovskite-based photovoltaic products in China and includes an additional right to sublicense.

A statement from Oxford PV says that its patent license agreement with Trina Solar “validates perovskite PV as the technology ready to define the future of solar” while consolidating the company’s position at the center of the perovskite ecosystem. The statement adds that the agreement reflects a growing trend of patent recognition and IP in China and will enable faster deployment of high-efficiency solar at GW scale.

Swedish thin film solar cell manufacturer Midsummer has been chosen by the Italian Ministry of University and Research to participate in a consortium with the aim to develop "Quantum Dot CIGS/Perovskite Tandem" solar cells.

The "Quantum Dot Enhanced Lightweight Solar Cells" (QDELS) project aims to develop and validate a new production process for CIGS (Cu In Ga Se) solar cells with a tandem perovskite structure enhanced with quantum dots (QD). The ultimate objective is to develop and validate a new process to enhance the efficiency of CIGS cells, surpassing conventional silicon cells in all parameters.

The inhomogeneity of hole-selective self-assembled molecular layers (SAMLs) often arises from the insufficient bonding between anchors and metal oxides, particularly on textured silicon surfaces when fabricating monolithic perovskite/silicon tandem solar cells (P/S-TSCs) and the hydrophobic carbazole complicates the fabrication of high-quality perovskite films. 

To address this, researchers from the Chinese Academy of Sciences (CAS), Advanced Solar Technology Institute of Xuancheng and North Minzu University have developed a bidentate-anchored superwetting aromatic SAM based on an upside-down carbazole core as a hole-selective layer (HSL), denoted as ((9H-carbazole-3,6-diyl)bis(4,1-phenylene))bis(phosphonic acid) (2PhPA-CzH). 

Researchers from Chung-Ang University (CAU), Kyoto University, Chungnam National University, Chungbuk National University and Gyeongsang National University have developed a halogen composition–independent strategy for realizing wide-bandgap (WBG) tin-based perovskite solar cells (TPSCs), by partially substituting formamidinium with dimethylammonium (DMA) in the A-site of the perovskite lattice. This substitution is said to expand the lattice, widening the bandgap from 1.63 to 1.72 eV without requiring additional bromine. 

Schematic of the ST-TPSC device structure. Image credit: Small

Comprehensive structural and optical analyses revealed enhanced crystallinity, reduced strain, and improved film morphology. Furthermore, ultraviolet photoelectron spectroscopy confirmed enhanced band alignment with the hole transport layer, enabling more efficient charge extraction. 

China-based Leascend PV has announced a remarkable milestone when its perovskite-silicon heterojunction tandem cell efficiency was certified at 32.99% by the National Photovoltaic Product Quality Supervision and Inspection Centre.

To overcome the issue of non-radiative carrier recombination at the perovskite-HJT interface, the Company chose to carefully adjust the size of the pyramid-like texture on the surface, enabling them to solve the problem of leakage paths due to incomplete perovskite layer coverage on large textured areas. This adjustment was critical to the proper growth of the perovskite layer and subsequent increase in efficiency.

Trina Solar’s National Key Laboratory of Photovoltaic Science and Technology has developed a 3.1 square meter, 210-unit perovskite-silicon dual-junction tandem module, validated by the internationally renowned TÜV SÜD. 

With a peak power output of 808W, this module has been referred to as 'the world’s first industry-standard photovoltaic module to surpass the 800W power milestone'. Since 2014, Trina Solar has been involved in researching perovskite tandem technology. It has formed strategic partnerships with universities and research institutes, such as Nanjing University and Nankai University. Together, they undertook scientific endeavors, including Jiangsu Province’s science and technology support projects and national key research and development programs. 

Researchers from the CitySolar project have announced an efficiency record for transparent solar cells. By combining organic solar cells with perovskite-based ones, the scientists were able to achieve an efficiency of 12.3%.

These cells could be used for building-integrated photovoltaics, transforming windows into solar panels. “Transparent solar cells could be the next big step in building-integrated energy solutions,” said Professor Morten Madsen from the University of Southern Denmark, who was one of the key researchers behind the breakthrough. “The large glass facades found in modern office buildings can now be used for energy production without requiring additional space or special structural changes... This represents a massive market opportunity.”