Technical / research - Page 5

Researchers from Russia's ITMO, EPFL in Switzerland, UNAM in Turkey, UK's University of Sheffield and Germany's Technische Universität Dortmund have demonstrated, reportedly for the first time, that halide perovskites can serve as a base for nonlinear on-chip optical components. 

Propagation of exciton-polariton wave packets in a waveguide based on halide perovskites. Photo credit: ACS Nano

As an example, they can be used to build ultrafast optical chips and transistors, and, potentially, other integrated optical systems. Unlike other materials, halide perovskites can operate at room temperature and are inexpensive to produce.

Researchers from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Lawrence Berkeley National Laboratory, University of California and Pohang University of Science and Technology (POSTECH) have observed and identified the water-induced degradation mechanism of perovskite in real time at the atomic scale. 

Image from: Matter

This recent study presents key strategies for enhancing the stability of perovskite materials and could accelerate their commercialization. 

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.

A team of researchers from DGIST, led by Professor Chang-Hee Cho, has successfully demonstrated the control of polaritons using ferroelectricity induced by crystallographic phase transition - The study offers key insights into next-generation quantum light sources and proposes a new direction for the realization of practical quantum devices.

The team successfully fine-tuned the Rabi oscillation of polaritons, quantum composite particles, by leveraging changes in electrical properties induced by crystal structure transformation. This study demonstrates that the properties of quantum particles can be controlled without the need for complex external devices, which is expected to greatly enhance the feasibility of practical quantum technology.

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). 

Researchers from EPFL, National University of Singapore and Nanjing University of Aeronautics and Astronautics have used lattice strain to lock in rubidium, which helped cut energy loss and push perovskite solar cells to 93.5% of their theoretical efficiency limit. By utilizing the controlled distortion in the atomic structure, this approach not only stabilized the wide-bandgap (WBG) perovskite but also improved efficiency by cutting non-radiative recombination, a major cause of energy loss.

Known for absorbing high-energy light while letting lower-energy light pass, wide-bandgap materials offer major gains in energy capture but are prone to phase segregation, a phenomenon that takes place when different components of the material separate over time, leading to a decline in performance. While adding rubidium to help stabilize the semiconductors has been proposed as a potential way to address the issue, the element often forms unwanted secondary phases, which limits its ability to strengthen the perovskite structure. However, the scientists fine-tuned the material’s composition in a process that involved rapid heating followed by controlled cooling. This created lattice strain, that prevented rubidium from forming unwanted secondary phases and kept it integrated within the crystal structure.

Researchers from the University of Potsdam, TU Berlin, HZB, BHT Berlin and Salerno University have reported halide perovskite photovoltaics (PV) fabricated on regolith-based moonglass that could be produced on the Moon, thereby saving 99% of material transport weight. Regolith is a silicate-rich material that covers the Moon’s surface. 

Image from: Device

This method reportedly enables effective specific power ratios, over 22–50 W/g, a factor of 20–100 higher compared to traditional space PV solutions, while not compromising radiation shielding, reliability, and mechanical stability as was the case until now. 

A research team from Ulsan National Institute of Science and Technology (UNIST), University of New South Wales, University of Surrey and 
Korea Research Institute of Chemical Technology have developed an interlayer that leverages the specificity of organic cations on the surface of perovskite solar cells (PSCs), simultaneously achieving high-efficiency and durability.

Credit: Joule (2025)

PSCs generate electrical energy by transferring charge carriers created when the light-absorbing material absorbs sunlight to the electrodes. Minimizing defects in this light-absorbing layer is essential for effectively delivering charges to the electrodes and enhancing cell efficiency. Previously, research focused on the use of single organic cations, which posed challenges such as structural collapse of the thin films due to the migration of individual cations and energy level misalignment. Energy levels serve as a "staircase" pathway for charge movement; if the interlayer energy levels are misaligned, charge losses can occur, leading to reduced efficiency.

The continuous dimensional scaling of semiconductor and logic photoelectric device requires ferroelectrics to possess robust photoelectric activity and switchable polarization at the nanoscale. However, traditional ferroelectrics such as oxide perovskites generally suffer from relatively large bandgap and deteriorated ferroelectricity in ultrathin forms, while the polarization in many transition metal dichalcogenides is related to inter-layer effects, leading to ferroelectricity that only exists in flakes with a certain layer number and particular stacking forms. The associated challenging fabrication and high-cost synthesis of inorganic ferroelectrics currently render mass industrial production of ultrathin ferroelectric semiconductors impossible. 

Now, researchers from the University of Nebraska Lincoln, University of Warwick and Heidelberg University have used (isopentylammonium)₂(ethylammonium)₂Pb₃I₁₀ (PEPI) to develop an organic-inorganic hybrid perovskite nanoflake with low-cost solution synthesis, switchable polarization, a narrow bandgap (1.86 eV to 2.21 eV form bulk to monolayer), and robust photoelectric properties down to the monolayer. The recent work reveals the great potential of 2D hybrid perovskite ferroelectrics as low-cost ferroelectric semiconductors at the nanoscale.