Technical / research

Researchers obtain direct visualization of structural dynamics in monocrystalline 2D perovskites

Scientists at Rice University, INSA Rennes, SLAC National Accelerator Laboratory and Northwestern University have managed to directly visualize the structural dynamics in monocrystalline 2D perovskites. While researchers already knew the atoms in perovskites react to light, direct visualization of these reactions is considered a long-standing challenge. Now, it's been made possible to see precisely how those atoms move.

The team's study details the first direct measurement of structural dynamics under light-induced excitation in 2D perovskites. “The next frontier in light-to-energy conversion devices is harvesting hot carriers,” said Rice University’s Aditya Mohite, a corresponding author of the study. “Studies have shown that hot carriers in perovskite can live up to 10-100 times longer than in classical semiconductors. However, the mechanisms and design principles for the energy transfer and how they interact with the lattice are not understood.”

Read the full story Posted: Jan 31,2023

Researchers develop highly efficient p-i-n perovskite solar cells while tackling the issue of endurance to temperature variations

Researchers from Helmholtz-Zentrum Berlin (HZB), Chinese Academy of Sciences (CAS), Swansea University, University of Stuttgart, Henan University, University of Naples Federico II, Queen Mary University of London and Soochow University have investigated a chemical variation that significantly improves the stability of the perovskite thin film in different solar cell architectures, among them the p-i-n architecture.

Daily temperature variations induce phase transitions and lattice strains in halide perovskites, challenging their stability in solar cells. The international team in this work set out to address this issue and improve the stability of PSCs in the face of these changes. 

Read the full story Posted: Jan 28,2023

Researchers develop metal oxide barrier coating to protect perovskite photovoltaics from terrestrial and space stressors

Researchers from the US Department of Energy’s National Renewable Energy Laboratory (NREL), University of North Texas and University of Oklahoma have demonstrated that an ultrathin layer of  silicon oxide layer can harden perovskite photovoltaics to protect it from critical stressors in space and on Earth. 

Space has its own unique environmental challenges for solar cells, perovskite ones included. PSCs have to be resilient against such challenges as “radiation, atomic oxygen, vacuum, and high-temperature operation,” according to the study’s abstract.

Read the full story Posted: Jan 27,2023

Researchers examine interfacial interactions of lead-free perovskites for efficient hydrogen production

A research team from City University of Hong Kong (CityU), Curtin University, National Taiwan University, Huazhong University of Science and Technology, Nankai University and Polish Academy of Sciences recently developed a lead-free perovskite photocatalyst that delivers highly efficient solar energy-to-hydrogen conversion.

The team unveiled the interfacial dynamics of solid-solid (between halide perovskite molecules) and solid-liquid (between a halide perovskite and an electrolyte) interfaces during photoelectrochemical hydrogen production. The latest findings open up an avenue to develop a more efficient solar-driven method for producing hydrogen fuel in the future.

Read the full story Posted: Jan 18,2023

Researchers fabricate solar cells based on gold polyhalide hybrid perovskite

Researchers at the Research Institute of Sweden (RISE) and KTH Royal Institute of Technology have presented the ionic liquid (IL) synthesis of two novel pseudo-2D perovskite-type gold(III)polyiodide compounds and their use as active layers in monolithic solar cells.

The team stated that its recent work represents the first demonstration of film deposition of gold iodide/polyiodide compounds onto porous monolithic substrates with subsequent solar cell characterization. The devices reportedly showed promising photovoltaic performance and could unlock new materials design possibilities, ultimately moving away from lead-based photovoltaic materials. These findings further highlight the use of simple polyiodide entities to increase the structural and electronic dimensionality of gold perovskite-type anions.

Read the full story Posted: Jan 14,2023

Researchers turn to facet engineering for more stable perovskite solar cells

Researchers at Switzerland's EPFL and Sungkyunkwan University in Korea have addressed the issue of perovskite solar cells' stability. They focused on the degradation of perovskite thin films, which can be damaged by exposure to moisture, heat, and light. The team looked at two specific crystal facets (the crystal's flat surface), characterized by a particular arrangement of atoms. The arrangement of atoms on these facets can affect the properties and behavior of the crystal, such as its stability and its response to external stimuli like moisture or heat.

The researchers looked at the (100) and (111) facets of perovskite crystals. The (100) facet is a plane that is perpendicular to a crystal's c-axis with its atoms arranged in a repeating pattern in the form of a square grid. In the (111) facet the atoms are arranged in a triangular grid. The study found that the (100) facet, which is most commonly found in perovskite thin films, is particularly prone to degradation as it can quickly transition to an unstable, inactive phase when exposed to moisture. In contrast, the (111) facet was found to much more stable and resistant to degradation.

Read the full story Posted: Jan 13,2023

Researchers reach >28% efficiency with perovskite-silicon tandem PV cell with textured wafers

Scientists from Saudi Arabia’s King Abdullah University of Science and Technology (KAUST), Deutsches Elektronen-Synchrotron DESY, Academy of Sciences of the Czech Republic and Slovak Academy of Sciences have demonstrated a power conversion efficiency of 28.1% for a perovskite-silicon tandem solar cell based on textured silicon wafers.

Textured silicon wafers used in silicon solar cell manufacturing offer superior light trapping, which is a critical enabler for high-performance photovoltaics. The team explained that a similar optical benefit can be obtained in monolithic perovskite/silicon tandem solar cells, enhancing the current output of the silicon bottom cell. Yet, such complex silicon surfaces may affect the structural and optoelectronic properties of the overlying perovskite films.

Read the full story Posted: Jan 12,2023

Perovskite absorbers enable solar-powered system that converts plastic and greenhouse gases into sustainable fuels

Researchers from the University of Cambridge have developed a system that can transform plastic waste and greenhouse gases into sustainable fuels and other valuable products – using energy from the Sun. The team states that this is the first time that a system that can convert two waste streams into two chemical products at the same time has been achieved in a solar-powered reactor.

The reactor converts carbon dioxide (CO2) and plastics into different products that are useful in a range of industries. In tests, CO2 was converted into syngas, a key building block for sustainable liquid fuels, and plastic bottles were converted into glycolic acid, which is widely used in the cosmetics industry. The system can easily be tuned to produce different products by changing the type of catalyst used in the reactor. The integrated reactor, which uses a light absorber based on perovskites, has two separate compartments: one for plastic, and one for greenhouse gases. 

Read the full story Posted: Jan 10,2023

Swedish-Israeli research team will study the self-healing abilities of perovskite solar cells

A research collaborative project involving scientists from Sweden's Karlstad University and Israel's Ben-Gurion University of the Negev and Weizmann Institute of Science will examine how perovskite solar cells could recover and self-repair at night.

Metal halide perovskite materials have been shown to possess a self-repairing ability. One of the Israeli research teams have shown that metal halide perovskite solar cells, which degrade in sunlight, can rebuild their efficiency at night, when it’s dark. The other Israeli research team exposed single crystals of lead-based metal halide perovskites to powerful lasers, which made them lose their ability to glow. The researchers then found that the material regained its photoluminescence following some recuperation time in darkness. Even if these two observations — one in the solar cell’s thin, multicrystalline layer and the other one in single crystals — seem related, the potential relation between these two phenomena still needs to be better understood, and how it works.

Read the full story Posted: Jan 09,2023

Researchers report on novel approach for high performance and spectrally stable deep-blue perovskite LEDs

Researchers from Yonsei University, Sungkyunkwan University and Institute for Basic Science (IBS) have proposed a rapid crystallization method based on hot-antisolvent bathing for realization of deep-blue  perovskite light-emitting diodes (PeLEDs). The rapid crystallization method manipulates 2D perovskite phase evolution by controlling the crystallization kinetics for the fabrication of phase-pure 2D Ruddlesden‒Popper perovskites (2D-RPPs), enabling deep-blue-emissive perovskite LEDs.

PeLEDs are considered as promising candidates for next-generation solution-processed full-color displays. However, the external quantum efficiencies (EQEs) and operational stabilities of deep-blue (<460 nm) PeLEDs still lag far behind their red and green counterparts. 2D-RPPs have excellent optoelectronic properties—ideal for LEDs. Although 2D-RPP-based LEDs have rapidly progressed in terms of performance, it is still challenging to demonstrate blue-emissive and color-pure LEDs. The deep blue of current LED displays is usually produced by indium gallium nitride (InGaN), a costly substance. In the field of LEDs, researchers are seeking alternatives and one of them could be found in 2D-RPPs.

Read the full story Posted: Jan 06,2023