Efficiency

Researchers from Wuhan University, South China Normal University and Chinese Academy of Sciences (CAS) have  explained that while all-perovskite tandem solar cells (TSCs) offer exceptional performance and versatile applicability, a significant challenge persists in bridging the power conversion efficiency (PCE) gap between small- and large-area (>1 cm²) devices, which presents a barrier to the commercialization of all-perovskite TSCs. 

Now, the team introduced a specialized crystal-modifying agent, piracetam, tailored for wide-bandgap perovskites, homogenizing top wide-bandgap subcells and enabling the construction of efficient large-area TSCs. 

Scientists at the Chinese Academy of Sciences (CAS), Xuancheng Kaisheng New Energy Technology Company and Tianjin Institute of Power Sources have found a way to make flexible tandem solar cells more efficient and durable by enhancing the adhesion of top layers to the bottom layers of the cell.

Copper indium gallium selenide (CIGS) is a commercial semiconductor known for its outstanding adjustable bandgap, strong light absorption, low-temperature sensitivity, and superior operational stability, making it a promising candidate for bottom-cell use in next-generation tandem solar cells. Flexible perovskite/CIGS tandem solar cells combine a top layer of perovskite with a bottom layer of CIGS. This tandem cell holds great potential for lightweight, high-efficiency applications in the photovoltaic field but the rough surface of CIGS makes it difficult to produce high-quality perovskite top cells on top, which limits the commercial prospects of these tandem cells.

Researchers at Queensland University of Technology (QUT) have developed an eco-friendly method to fabricate perovskite solar cells (PSCs) by incorporating a fluoride additive into a water-based solution. This approach eliminates the use of toxic solvents typically required in PSC production, while achieving power conversion efficiencies above 18%.

The team introduced lead(II) fluoride (PbF₂) into the water-based precursor solution to regulate crystal growth dynamics and improve film quality. The fluoride additive accelerated the formation of the photoactive phase and promoted the crystallization orientation, both critical for efficient solar energy conversion.

LONGi has once again announced a new efficiency record for its proprietary dual terminal perovskite-silicon tandem solar cell - 34.85%, certified by the US National Renewable Energy Laboratory (NREL).

LONGi’s research team is on a roll. In November 2023, they increased cell efficiency to 33.9%. Then, in June 2024, they pushed it up to 34.6%. And now, in less than a year, they’ve catapulted it to 34.85%.

Researchers at The University of Queensland have reported a 'new world record efficiency for lead-free perovskite solar cells'.

A team led by Professor Lianzhou Wang, based at the Australian Institute for Bioengineering and Nanotechnology (AIBN) and the School of Chemical Engineering, achieved a breakthrough certified efficiency of 16.65% using tin-based perovskite - a non-toxic alternative to the lead typically used in next-generation solar cells.

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.

NiOx shows promise for large-area perovskite technologies thanks to excellent semiconductor properties, ease of large-area deposition, and tunable optoelectronic characteristics. However, NiOx-based perovskite solar cells (PSCs) tend to be limited by interfacial photocatalytic chemical reactions and energy level mismatch. Thus, phosphate-based self-assembled monolayers (SAMs) have been developed for delicate interfacial modification but these suffer from severe issues such as self-aggregation and high cost.

Image from: Journal of Energy Chemistry

Researchers from China's Fudan University and Shanghai Geoharbour Construction Group have addressed this issue by developing a low-cost carboxylate-based SAM (pyrenebutyric acid, PyBA) to modify NiOx, achieving an improved surface chemical environment and interfacial properties, such as an increased Ni³⁺/Ni²⁺ ratio, a reduced proportion of high-valence Ni^≥3+, and better-aligned hole transport interface energy level. 

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).