Technical / research - Page 4

Researchers create full-color fiber light-emitting diodes based on perovskite quantum wires

Researchers from the Hong Kong University of Science and Technology, Sun Yat-sen University and Nanjing University of Science and Technology have uniformly grown all-inorganic perovskite quantum wire arrays by filling high-density alumina nanopores on the surface of Al fibers with a dip-coating process. 

Fiber light-emitting diodes (Fi-LEDs), which can be used for wearable lighting and display devices, could be a key component for fiber/textile electronics. However, as a number of challenges exist with this technology, researchers are trying to address issues like on device fabrication with fiber-like substrates, as well as on device encapsulation.

Read the full story Posted: May 16,2024

Researchers develop perovskite/organic tandem device for dual light detection and emission functions

Researchers at China's Nanjing University of Science and Technology, Hong Kong Baptist University and Southwest University have introduced a tandem device that incorporates an organic photodiode (OPD) and a perovskite light emitting diode (PeLED), enabling simultaneous light detection and emission in one compact device, prepared by all-solution fabrication process. 

The team found that precise control of interfacial properties plays a critical role in establishing the all-solution processed OPD/PeLED multi-layered dual-function device which is critical for charge transport, recombination, and generation. 

Read the full story Posted: May 15,2024

Researchers develop efficient inkjet-printed perovskite solar cells

Researchers from Germany's Karlsruhe Institute of Technology (KIT) have developed a scalable two-step evaporation and inkjet process for perovskite thin-film solar cells. The new technique is said to enable champion cells with the same efficiencies as those made with the spin coating process.

The process is described as a scalable and reliable technique for high-quality perovskite deposition, which combines the use of an evaporated lead iodide layer with inkjet-printed organic perovskite precursor materials. It is also said to exhibit high reproducibility and potential for conformal growth on textured silicon, and that provide films that are free of drying effects and toxic solvents.

Read the full story Posted: May 14,2024

Researchers develop high-efficiency pure red light-emitting diodes through surface modification of perovskite QDs

Researchers from Korea's Daegu Gyeongbuk Institute of Science and Technology (DGIST), Ulsan National Institute of Science and Technology (UNIST) and Institute for Basic Science (IBS) recently developed high-performance, skin-attachable perovskite pure red light-emitting devices to create various forms of wearable displays.

The team developed these devices through selective surface modification of perovskite quantum dots, expecting their future use in diverse wearable products. As traditional red perovskite materials were unsuitable for high-performance wearable displays due to their low stability and electrical properties, the research team created pure red light-emitting devices through the simple surface modification of the perovskite light-emitting layers, thus significantly improving their stability and electrical properties.

Read the full story Posted: May 12,2024

Researchers use dopant-additive synergism to develop perovskite solar module with efficiency of 23.3%

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.

Read the full story Posted: May 11,2024

Researchers report an optofluidic crystallithography method for directed growth of single-crystalline halide perovskites

Crystallization, the phenomenon that transforms disordered atoms or molecules into ordered solid-state structures, is an immensely studied process. However, while researchers have made significant strides in controlling the nucleation of crystals from precursor solutions, directing their subsequent growth to form defect-free single crystals with tailored shapes has proven far more challenging. This limitation has been particularly problematic for materials like halide perovskites, where controlling the formation of defects results in better photoelectric properties. Conventional techniques like inverse temperature crystallization or antisolvent vapor-assisted crystallization allow some control over average growth conditions, but their ability to pattern arbitrary single-crystal geometries while suppressing defect formation has remained confined.

Now, researchers at Tsinghua University have demonstrated optofluidic crystallithography (OCL), a novel approach that leverages a laser as a precise "pen" to simultaneously control the shape and quality of single-crystal halide perovskites as they grow from solution at record speeds.

Read the full story Posted: May 10,2024

Researchers design tin-germanium-based perovskite solar cell with potential efficiency of up to 31.49%

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.

Read the full story Posted: May 09,2024

Researchers develop room-temperature-processed perovskite solar cells with >24% efficiency

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. 

Read the full story Posted: May 08,2024

Researchers develop crystalline 2D fullerene-based metal halide semiconductor for efficient and stable perovskite solar cells

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 FA0.6MA0.4Pb0.7Sn0.3I3 perovskite and a C60 layer reportedly offered superior band energy alignment, reduced nonradiative recombination, and enhanced carrier mobility.

Read the full story Posted: May 06,2024

Researchers design dynamical self-rectifying memristors based on halide perovskite nanocrystals

Researchers from China's Shenzhen Campus of Sun Yat-sen University have reported a new type of two-terminal self-rectifying memristor that gets rid of asymmetric complex structures by using CsPbBr3 perovskite nanocrystals (NCs). The integration of rectifying effects with resistance switching in a self-rectifying memristor offers the opportunity to suppress the sneak current in high-density crossbar arrays for energy-efficient neuromorphic computing.

This study demonstrates the possibility of constructing controllable self-rectifying memristors without involving asymmetric complex structures, paving a new way for resolving the sneak current issue in crossbar arrays of memristors. 

Read the full story Posted: May 05,2024