Technical / research - Page 10

Researchers from China's Zhejiang University, Westlake University, Southern University of Science and Technology, Chinese Academy of Sciences (CAS) and University of California Los Angeles in the U.S have reported a family of high-entropy organic–inorganic hybrid perovskites for photovoltaic applications.  

The scientists built, for the first time, an inverted perovskite solar cell relying on a high-entropy hybrid perovskite material. The result is a device with an improved open-circuit voltage and fill factor, due to reduced non-radiative recombinations and optimized interface.

Researchers from Zhejiang University of Technology and King Abdullah University of Science and Technology (KAUST) have utilized two sulfone-based organic molecules known as diphenylsulfone (DPS) and 4,4′-dimethyldiphenylsulfone (DMPS) to passivate absorber defects in perovskite solar cells and improve their performance. As a result, the team reported a device with a higher electron cloud density at the interface between the perovskite material and the passivation layer.

The scientists used the molecules to improve charge distribution at the interface between the cell's perovskite absorber and the passivation layer, which reportedly creates electron-rich systems on the surface of perovskite. Using density functional theory (DFT) to compute a wide variety of properties of almost any kind of atomic system, they simulated the charge density distributions of the interactions of DPS and DMPS with formamidinium lead iodide (FAPbI₃) perovskite material.

Researchers from National Renewable Energy Laboratory (NREL), University of Utah, Université de Lorraine CNRS and University of Colorado Boulder have improved upon their previous work, that included incorporating a perovskite layer that allowed the creation of a new type of polarized light-emitting diode (LED) that emits spin-controlled photons at room temperature without the use of magnetic fields or ferromagnetic contacts. In their latest work, they have gone a step further by integrating a III-V semiconductor optoelectronic structure with a chiral halide perovskite semiconductor. 

The team transformed an existing commercialized LED into one that also controls the spin of electrons. The results could provide a pathway toward transforming modern optoelectronics, a field that relies on the control of light and encompasses LEDs, solar cells, and telecommunications lasers, among other devices.

Researchers from Zhejiang University, LinkZill Technology, Jilin University, and Linköping University have found that the electroluminescence rise time of perovskite LEDs (PeLEDs) can be reduced to microseconds using an individual-particle passivation strategy. This addresses a known issue with PeLEDs, that tend to have electroluminescence rise times over milliseconds due to ion migration in crystal structure, which is problematic for the development of high-refresh-rate displays.

The team demonstrated a second-generation digital display screen that uses perovskite light-emitting diodes instead of standard LED technology. In their study, the group made improvements to the device and demonstrated its sensing capability.

Researchers from King Abdullah University of Science and Technology (KAUST) have reported four-terminal perovskite/perovskite/silicon triple-junction tandem solar cells, with the device structure comprising a perovskite single-junction top cell and monolithic perovskite/silicon tandem bottom cell.

The cells reportedly yielded a 31.5% power conversion efficiency, which the team said is the highest efficiency ever reported for perovskite-based 4-T and triple-junction tandem solar cells. The key feature of the cell is the hole transport layer of the top perovskite cell, which was engineered with self-assembled monolayers.

Researchers from Harbin Engineering University, ITMO University and Hellenic Mediterranean University have managed to improve perovskite solar cells with the help of silicon nanoantennas, which increase the concentration of light in the material at certain wavelengths. The team applied monodisperse silicon nanoparticles to investigate optical effects responsible for the improvement of perovskite solar cells. This method could someday be used to create solar cells for indoor lighting and even the space industry. 

Solar cells and batteries in general can be improved by developing semiconductor materials that efficiently absorb light. Perovskites are considered promising since they are light, thin, and easy-to-produce and can be used to make thin solar cells with varied bending shapes, low weight, and multiple applications. Like other semiconductors, perovskites, however, absorb just a fraction of the spectrum and therefore generate less energy than they receive from the source. To that end, the international team of scientists has developed perovskite solar cells using silicon-based optical resonant nanoantennas. 

Researchers from Colombia's Universidad de los Andes recently set out to develop inverted perovskite solar cells (IPSCs) with a hole transport layer based on indium-doped nickel oxide. The result is a champion device that achieved an efficiency of 20.06% with remarkable stability.

The team explained that NiOx has an energy gap of over 3.5 eV, exceptional chemical stability, durability, low toxicity, and cost-effective processing. The scientists said that in the case of NiOx-based inverted perovskite solar cells, the doping approach has indeed paved the way for HTL optimization, frequently through observable improvements also at the interface level and in the perovskite layer.

Researchers from Monash University, Xi’an Jiaotong University, Tunghai University, the University of Oxford, National Central University, and the City University of Hong Kong have developed a strategy to enhance the stability and performance of perovskite solar cells (PSCs) through a mechanism described as 'self-healing'.

The team reported a living passivation strategy using a hindered urea/thiocarbamate bond Lewis acid-base material (HUBLA), where dynamic covalent bonds with water and heat-activated characteristics can dynamically heal the perovskite to ensure device performance and stability. 

Researchers at The University of Texas at Austin (UT Austin) recently gained better understanding of the origin of halide perovskites' extraordinary carrier lifetimes, by showing that halide perovskites are governed by unconventional electron–phonon physics, leading to the formation of topological polarons, a class of phonon-mediated electron/hole quasiparticles. 

The team's findings suggest that halide perovskites may be regarded as a class of quantum materials where electron–phonon couplings replace the traditional electron–electron interactions of correlated electron systems.

Researchers at China's Shanghai University, Jilin University, University of Science and Technology of China, Chinese Academy of Sciences, Korea's Pohang University of Science and Technology (POSTECH) and UK's University of Cambridge have reported efficient and color-stable perovskite LEDs (PeLEDs) across the entire pure-red region, with a peak external quantum efficiency reaching 28.7% at 638 nm, enabled by incorporating a double-end anchored ligand molecule into pure-iodine perovskites.

Light-emitting diodes (LEDs) based on metal halide perovskites (PeLEDs) with high color quality and facile solution processing are promising candidates for full-color and high-definition displays. However, the team explained that despite the great success achieved in green PeLEDs with lead bromide perovskites, it is still challenging to realize pure-red (620–650 nm) LEDs using iodine-based counterparts, as they are constrained by the low intrinsic bandgap.