Efficiency

Researchers from the University of Stuttgart, Lawrence Berkeley National Laboratory and Brandenburg University of Technology Cottbus-Senftenberg have introduced a simplified deposition procedure for multidimensional (2D/3D) perovskite thin films, integrating a phenethylammonium chloride (PEACl)-treatment into the antisolvent step when forming the 3D perovskite. 

The “traditional” deposition and passivation processes (top row) and the integrated deposition and passivation strategy to form 2D passivated 3D halide perovskite films (bottom row). Image from Advanced Materials.

This recently developed simultaneous deposition and passivation strategy reduces the number of synthesis steps while simultaneously stabilizing the halide perovskite film and improving the photovoltaic performance of resulting solar cell devices to 20.8%. 

Researchers at Austria's Johannes Kepler University Linz have developed lightweight, thin (<2.5 μm), flexible and transparent-conductive-oxide-free quasi-two-dimensional perovskite solar cells by incorporating alpha-methylbenzyl ammonium iodide into the photoactive perovskite layer. 

The team fabricated the devices directly on an ultrathin polymer foil coated with an alumina barrier layer to ensure environmental and mechanical stability without compromising weight and flexibility. 

Scalable deposition of high-efficiency perovskite solar cells (PSCs) is vital to achieving commercialization. However, a significant number of defects are distributed at the buried interface of perovskite film fabricated by scalable deposition, which adversely affects the efficiency and stability of PSCs. Now, researchers at China's Central South University, Hunan Institute of Engineering and  Chinese Academy of Sciences (CAS) addressed this issue by incorporating 2-(N-morpholino)ethanesulfonic acid potassium salt (MESK) as the bridging layer between the tin oxide (SnO₂) electron transport layer (ETL) and the perovskite film deposited via scalable two-step doctor blading. 

The scientists reported that both experiment and simulation results demonstrated that MESK can passivate the trap states of Sn suspension bonds, thereby enhancing the charge extraction and transport of the SnO₂ ETL. 

Researchers from Northwestern University, University of Toronto, ShanghaiTech University, University of Victoria and Arizona State University have developed highly stable, highly efficient 0.05cm² perovskite solar cell with a PCE of 26.15%, certified by a National Renewable Energy Laboratory-accredited facility. The team said that the prior certified world record published in a scientific journal was 25.73%.

A 1.04 cm² device had a certified power conversion efficiency of 24.74%, also a record for its size. The best devices retained 95% of their initial PCE following 1,200 hours of continuous solar illumination at a temperature of 65 degrees.

Researchers from the University of Freiburg and Fraunhofer ISE recently put together a roadmap for the optical properties of perovskite/perovskite/silicon triple-junction cells. They investigated the optical properties of perovskite/perovskite/silicon triple-junction cells and found these devices may have a practical efficiency potential of 44.3% assuming idealized electrical parameters. These cells may also potentially achieve a fill factor of 90.1%.

The group of researchers developed a comprehensive optoelectrical simulation model for triple-junction solar cells based on subcells relying on perovskite, perovskite, and crystalline silicon, respectively. The model aims to define an efficiency roadmap for improving the optical properties of these solar cells within realistic boundary conditions.

Researchers at Shanghai Jiao Tong University, Shanghai University of Electric Power and Shandong Normal University have addressed the traditional trial-and-error method for preparing high-efficiency perovskite solar cells (PSCs) by introducing a goal-driven approach that integrates machine learning and data mining techniques to rapidly screen high-efficiency PSCs based on key features. 

By predicting high-efficiency PSCs and identifying the dominant factors affecting their performance, namely the perovskite bandgap and the total thickness of the electron transport layer (ETL), this research aims to provide valuable insights for optimizing preparation processes and advancing the development of high-efficiency PSCs, thus significantly contributing to the renewable energy sector.

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 China's Tsinghua University, Zurich University of Applied Sciences and University of Ferrara have developed a perovskite solar cell with a new hole transport material that promises enhanced efficiency and stability while also ensuring a scalable fabrication technique.

The team explained that the new organic hole-transporting material, named T2, offers a performance advantage over conventional materials like spiro-OMeTAD as its characteristics, including unique electronic, structural, and chemical properties, synergistically enhance the efficiency of hole extraction and significantly reduce charge recombination at the interface with the perovskite layer.

High power conversion efficiency (PCE) flexible perovskite solar cells (FPSCs) are highly desired power sources for applications like aerospace and flexible electronics. However, their PCEs still lag far behind their rigid counterparts. To address this issue, researchers from Tsinghua University and National Center for Nanoscience and Technology developed a new fabrication technique that increases the efficiency of FPSCs, paving the way for use of the technology on a much larger scale. The scientists reported a high PCE flexible perovskite solar cell by controllable growth of a SnO₂ electron transport layer through constant pH chemical bath deposition (CBD). 

The team developed a new chemical bath deposition (CBD) method of depositing tin oxide (SnO₂) on a flexible substrate without requiring a strong acid, which many flexible substrates are sensitive to. The new technique allowed the researchers more control over tin oxide growth on the flexible substrate. Tin oxide serves as an electron transport layer in the FPSC, which is critical for power conversion efficiency.