Efficiency

Researchers at China's Shanghai University of Electric Power have used dibenzoylmethane (DBM) as a precursor additive introduced in order to regulate the crystallization of CsPbI₂Br perovskite while passivating its associated defects. 

Inorganic CsPbI₂Br perovskite solar cells (PSCs) have attracted massive interest but the tendency towards unruly crystallization and poor film quality of inorganic CsPbI₂Br perovskites are major factors limiting their performance improvement. In their recent work, the scientists used DBM additive engineering for efficient and stable carbon-based CsPbI₂Br PSCs.

Researchers from India's Chiktara University have reported improved stability and performance of organic-inorganic perovskite solar cells by applying a strategy called bandgap grading.

The method is based on enabling the cell perovskite absorber to collect a wider range of light photons by modifying its thickness and characteristics. The team explains that its recent study demonstrates the effectiveness of both linear and parabolic bandgap grading strategies in optimizing light absorption and boosting performance, showing its potential. 

China-based RenShine Solar has announced that following the completion and commissioning of its 150MW perovskite photovoltaic module project in January, 2024, the Company's 1.2*0.6㎡ commercial size single-junction perovskite was certified by the China Institute of Metrology. The steady-state efficiency of the entire module area reportedly reaches 18.4%.

The production line aims to achieve mass production of 1.2m*0.6m perovskite modules with 20% efficiency by mid-2024. It plans to develop gigawatt-scale production lines to further expand its capacity.

Researchers from EPFL, Soochow University, Chinese Academy of Sciences, Lomonosov Moscow State University, Luxembourg Institute of Science and Technology (LIST), Julius Maximilian University of Würzburg, Toin University of Yokohama, Southern University of Science and Technology, Xi’an Jiaotong University, North China Electric Power University and Toyota Motor Europe recently developed a solar panel relying on EPFL's record-breaking 25.32%-efficient 2D/3D perovskite solar cells unveiled in July 2023.

The group's research demonstrates a larger surface area of 27.22 cm², achieving an impressive efficiency of 23.3%. In the paper, the scientists explain that the module's high efficiency was achieved thanks to a synergistic dopant-additive combination strategy aimed to improve the cell absorber's uniformity and crystallinity. They used, in particular, methylammonium chloride (MACl) as a dopant and a Lewis-basic ionic liquid known as 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl) as an additive.

Researchers from Malaysia have simulated a mixed cation solar cell based on a perovskite absorber integrating tin (Sn) and germanium (Ge) as mixed B cations. By modulating the perovskite layer thickness, they achieved an efficiency ranging of 24.25% - 31.49%.

Perovskite absorbers using mixed cations have the potential to improve stability, light absorption, and charge carrier mobility. A cations are used to control the bandgap and stability of the perovskite material, while B cations are intended to modify electrical and optical characteristics of perovskites. The scientists explained that using both elements in the B cation via “compositional engineering ” enables to reduce their respective defects and increase the cell performance, when compared to using each of them separately. Furthermore, the Ge atoms can replace Sn atoms in the perovskite crystal structure.

Researchers at UC Santa Barbara, Pusan National University and Korea Electric Power Research Institute have introduced a simple approach to produce high-quality perovskite films at room temperature by precisely regulating the perovskite composition with the addition of an organic linker (oleylamine, OAm). This work aims to address the challenge presented by current processes for manufacturing PSCs - that tend to rely on high-temperature annealing and intricate post-treatments.

The team’s innovation not only simplified the production process but also increased the material’s efficiency from under 20% to 24.4%. The method enabled phase conversion to the stable α-phase without thermal annealing, as confirmed by in situ X-ray monitoring. The optimized device achieved impressive efficiencies of 23.2% (24.4% with an anti-reflective coating), surpassing efficiencies attained by previous room/low-temperature-processed PSCs. 

Researchers from Wuhan University, University of South Florida, CNRS and Nanoneurosciences recently reported the first crystalline 2D Fullerene based Metal Halide Semiconductor, (C₆₀-2NH₃)Pb₂I₆.

Designing functionalized C60 adducts at the Spanopoulos Group at USF

According to the team, single crystal XRD studies elucidated the structure of the new material, while DFT calculations highlighted the strong contribution of C₆₀-2NH₃ to the electronic density of states of the conduction band of the material. Utilization of C₆₀-2NH₃ as an interlayer between a FA_0.6MA_0.4Pb_0.7Sn_0.3I₃ perovskite and a C60 layer reportedly offered superior band energy alignment, reduced nonradiative recombination, and enhanced carrier mobility.

Researchers from Soochow University, Hunan University and Friedrich-Alexander University Erlangen-Nürnberg have incorporated pseudo-halogen thiocyanate (SCN) ions in iodide/bromide mixed halide perovskites and showed that they enhance crystallization and reduce grain boundaries. 

While perovskite/organic tandem solar cells could theoretically achieve high efficiency and stability, their performance is hindered by a process known as phase segregation, which degrades the performance of wide-bandgap perovskite cells and adversely affects recombination processes at the tandem solar cells' interconnecting layer. The team devised a strategy to suppress phase segregation in wide-bandgap perovskites, thus boosting the performance and stability of perovskite/organic tandem cells. This strategy entails the use of a pseudo-triple-halide alloy incorporated in mixed halide perovskites based on iodine and bromine.

An international group of researchers, led by the Chungbuk National University in South Korea, has reported a tin halide perovskite (Sn-HP) solar cell that uses an additive known as 4-Phenylthiosemicarbazide (4PTSC) to reduce imperfections in the perovskite layer.

Using wide bandgap tin halide perovskites (Sn-HP) could pose an eco-friendly option for multi-junction Sn-HP photovoltaics, but rapid crystallization often results in poor film morphology and substantial defect states, hampering device efficiency. The team's work aims to introduce a novel multifunctional additive to tackle these issues.

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%.