Perovskite applications

Researchers from City University of Hong Kong have introduced a novel and durable 2D thermochromic perovskite, Tha₂MAPbI₄ (TMPI, Tha = thiourea, MA = methylamine), wherein Tha acts as a Lewis acid-base adduct. TMPI demonstrates a reversible transition, achieving 83.7% luminous transmittance in the cold state and 35.2% in the hot state, thereby showcasing a substantial solar modulation ability of 24.7%. 

The background for this development is that despite growing interest in thermochromic metal halide perovskite (MHPs) for smart window applications, existing MHP smart windows predominantly feature 3D perovskite, which exhibits a deficiency in environmental stability, presenting persistent challenges for practical applications. 

Saule Technologies has announces that it will work with H.I.S. Co., Ltd. and Lawson, Inc. to start a pilot demonstration using film-type perovskite solar cells at "Green Lawson" from Monday, December 16, 2024.

Lawson is a large chain of retail grocery stores based in Japan, and it was stated that the cooperation will include Perovskite Electronic Shelf Labels and Power Generation Panels.

Radiation detectors, which convert radiation into measurable light signals, currently come in fixed shapes like blocks or cylinders because they are made by growing crystals at extremely high temperatures – around 1700 °C. These rigid shapes make it difficult to measure radiation doses accurately around irregularly shaped tumors or in tight spaces. Previous attempts to create detectors in custom shapes have focused on plastic materials that can be easily molded, but these plastic detectors perform poorly because they lack the heavy elements needed to efficiently capture radiation. Scientists have tried mixing metal particles into plastics to improve their detection ability, but this often results in uneven distribution of the particles and poor overall performance.

A research team from several institutions in Italy and Switzerland has now developed a new approach using stereolithography (SLA), a precise form of 3D printing that builds objects by hardening light-sensitive liquid materials layer by layer. This marks the first successful use of SLA to fabricate 3D-printed scintillators, a breakthrough in radiation detection technology. The team mixed microscopic crystals of cesium lead bromide (Cs₄PbBr₆), a perovskite material, into a liquid resin that hardens when exposed to ultraviolet light. Perovskites have gained significant attention in recent years because they efficiently convert various forms of energy into light. Their crystal structure, which contains heavy elements like lead, makes them particularly effective at detecting radiation.

Researchers from the Chinese Academy of Sciences (CAS), Beihang University and Imperial College London have developed an on-chip integrated polarization photodetector (pol-PD), drawing inspiration from the unique polarization vision of desert ants.

Working mechanism diagram of the single-shot on-chip pol-PD. Image from Science Advances

Pol-PDs have widespread applications in geological remote sensing, machine vision and biological medicine. However, commercial pol-PDs usually require bulky and complicated optical components and are difficult to miniaturize and integrate. The researchers observed that desert ants can navigate back to their nests across barren landscapes without landmarks, thanks to their compound eyes' ability to detect polarized sunlight. They aimed to mimic this capacity with their pol-PD.

This is a sponsored post by Springer Nature 

Perovskite materials have captured the attention of researchers worldwide due to their remarkable properties and versatile applications. These materials are being extensively studied for use in solar cells, photodetectors, field-effect transistors, light-emitting diodes (LEDs), and spintronics. Perovskites are unique because they offer a combination of high efficiency, low manufacturing costs, and the potential for flexibility and transparency. This makes them highly attractive for various cutting-edge technologies.

Given the relevance of the topic and the growing significance of perovskite materials, Sharon George, Senior Editor, Product Management SpringerMaterials, collaborated with Springer Nature’s blog The Link and interviewed Nature Communications editors to gain some of their insights into Emerging Trends in Perovskite Research - find out more about her findings below.

Image 1: from One-step dual-additive passivated wide-bandgap perovskites to realize 44.72%-efficient indoor photovoltaics, Energy & Environmental Science – https://doi.org/10.1039/D3EE04022D

Advancements in photovoltaics: from tandem to indoor solar cells

Photovoltaics is one of the most hotly discussed topics in perovskite research. According to Natalie Lok Kwan Li (Senior Editor, Nature Communications), current research is heavily focused on improving the performance of solar cells and modules. One of the most exciting advancements in this area is the development of tandem solar cells. These cells combine perovskite materials with other semiconductors to achieve higher efficiencies than traditional single-junction solar cells.

Researchers from South China University of Technology, The Chinese University of Hong Kong, Chinese Academy of Sciences (CAS), National Center for Nanoscience and Technology, Friedrich-Alexander University Erlangen-Nürnberg and Linköping University set out to eliminate deep traps in inorganic narrow bandgap (NBG) perovskites, in order to enable the successful development of 2T inorganic perovskite tandem solar cells (IPTSCs).

The team explained that all-inorganic perovskites prepared by substituting the organic cations (e.g. methylammonium (MA⁺) and formamidinium (FA⁺)) with inorganic cations (e.g. Cs⁺) are effective concepts to enhance the long-term photo- and thermal-stability of perovskite solar cells (PSCs). Hence, inorganic perovskite tandem solar cells (IPTSCs) are promising candidates for breaking the efficiency bottleneck and addressing the stability issue as well. However, challenges in fabricating 2-terminal (2T) IPTSCs due to the inferior film formation and deep trap states induced by tin cations hinder that option. 

Researchers from Spain's UPV/EHU, ICIQ-BIST, CIDETEC and Mexico's Instituto Politécnico Nacional have explored the effect of chalcogen substitutions in fullerene derivatives to enhance efficiency and stability of perovskite solar cells.

The team examined the effects of chalcogen substitution in the chemical structure of phenyl-butyric acid methyl ester (PCBM) on the performance and stability of inverted perovskite solar cells (PSCs). PCBMs are the most widely used electron transport materials in inverted PSCs. However, these compounds can suffer from lack of stability under irradiation. In the race for optimizing the PCBM-like derivatives, the thiophene moiety has garnered significant attention for enhancing the performance and stability of PSCs. The novelty in this study relies on the tests done on the selenophene derivative. This compound was compared to thiophene and furan substituted derivatives, and to the reference PCBM without a chalcogenophene moiety, demonstrating a better surface passivation and reduced interfacial charge recombination.

Carbon-based all-inorganic perovskite solar cells (C-PSCs) are known for their inexpensive manufacturing process. However, their perovskite constituents are susceptible to the formation of numerous structural defects and halide vacancies, which can induce substantial energy level misalignments between the light-absorbing layer and the carbon electrode. This discrepancy hinders the extraction and transfer of holes, thereby adversely affecting the overall efficiency of the device. 

Image credit: Chemical Engineering Journal

Researchers from China's Huaqiao University have proposed an interfacial post-treatment strategy aimed at reinforcing perovskite layers through the application of Neostigmine bromide (NMB) as a modifier. The team employed NMB to treat the upper interface of the perovskite, addressing intrinsic phase segregation, passivating surface defects, and filling halogen vacancies, thereby enhancing the photoelectric performance and stability of the device.

Aiming to explore the potential of sulfur-based additives for increasing both device power conversion efficiency and moisture stability of perovskite solar cells, researchers from BCMaterials (Spain), Huazhong University of Science and Technology (China), Max Planck Institute for Polymer Research (Germany) and CNRS (France) have reported a mechanism for the local nanoscopic humidity ingression into a multifunctional additiviated formamidinium-loaded halide perovskites.

a) The molecular structure of additives used. Image from: Advanced Energy Materials

By tuning the iodide and bromide tails of the additives, the influence of sulfur heteroatom containing ammonium-amidinium salts on the photo-physical and device properties of a formamidinium-rich perovskite absorber was uncovered. 

Researchers from China's Jiangxi Normal University, Chinese Academy of Sciences (CAS) and City University of Hong Kong have developed a self-driven X-ray detection device using high resistivity zero-dimensional lead-free perovskite ferroelectric single-crystal (NMP)₃Sb₂Br₉. The device exhibits an excellent self-driven X-ray detection performance, with an ultra-low detection limit of 84.1 nGyair/s, approximately 60 times lower than that of commercial α-Se (5500 nGyair/s).

The self-driven detection mode without external bias has been proven to be an effective means of reducing the limit of detection (LoD) due to its low current noise characteristics. Additionally, the zero-dimensional distinctive isolated framework results in a high resistivity of 1.39 × 1011 W cm, which effectively reduces the current noise and suppresses ion migration.