Blue Light-Emitting Diodes Based on Pure Bromide Perovskites.

Blue perovskite light-emitting diodes (LEDs) are essential for the creation of full-color displays and white-light illumination, and some significant progress is made in recent years. However, most high-performance blue perovskite LEDs are currently based on mixed-halide perovskites and suffer from unstable spectra due to inevitable halide phase segregation, which is unfavorable for the application of blue perovskite LEDs. In contrast, blue emissions from pure bromide perovskites generally exhibit stable spectra (consistent emission peak positions and spectral shapes) and are worthy of attention.

Efficient and stable perovskite mini-module via high-quality homogeneous perovskite crystallization and improved interconnect.

The efficiency and stability of perovskite module devices are mainly limited by the quality of scalable perovskite films and sub-cells' lateral contact. Here, firstly, we report constant low temperature substrate to regulate the growth of perovskite intermediate films to slow down the crystallization for obtaining high-quality homogeneous perovskite films in large scale size, which avoid the effect of the ambient temperature on the film quality. Secondly, a scribing step named P1.

Efficient pure-red perovskite light-emitting diodes with strong passivation via ultrasmall-sized molecules.

Perovskite light-emitting diodes (PeLEDs) have attracted great attention in recent years; however, the halogen vacancy defects in perovskite notably hamper the development of high-efficiency devices. Previously, large-sized passivation agents have been usually used, while the effect of defect passivation is limited due to the weak bonding or the large space steric hindrance. Here, we predict that the ultrasmall-sized formate (Fa) and acetate (Ac) have more efficient passivation ability because of the stronger binding with the perovskite, as demonstrated by density functional theory calculation.

High-Efficiency Pure-Red Perovskite Quantum-Dot Light-Emitting Diodes.

It is still challenging to achieve high-efficiency pure-red (620-650 nm wavelength) perovskite light-emitting diodes (PeLEDs). Herein, we report pure-red PeLEDs with Commission Internationale de l'Eclairage coordinates (0.703, 0.

Red Perovskite Light-Emitting Diodes with Efficiency Exceeding 25% Realized by Co-Spacer Cations.

Perovskite light-emitting diodes (PeLEDs) have received great attention in recent years due to their narrow emission bandwidth and tunable emission spectrum. Efficient red emission is one of most important parts for lighting and displays. Quasi-2D perovskites can deliver high emission efficiency due to the strong carrier confinement, while the external quantum efficiencies (EQE) of red quasi-2D PeLEDs are inefficient at present, which is due to the complex distribution of different n-value phases in quasi-2D perovskite films.

Broadband Photodetector Based on Inorganic Perovskite CsPbBr /GeSn Heterojunction.

Photodetectors with broadband response spectrum have attracted great interest in many application areas such as imaging, gas sensing, and night vision. Here, a high performance broadband photodetector is demonstrated with inorganic perovskite CsPbBr /GeSn heterojunction, detection range can be covered from 450 to 2200 nm. The responsivity of heterojunction device can achieve as high as 129 mA W under illuminated light of 532 nm, which is 4.

Perovskite Light-Emitting Diodes with External Quantum Efficiency Exceeding 22% via Small-Molecule Passivation.

Perovskite light-emitting diodes (PeLEDs) are considered as particularly attractive candidates for high-quality lighting and displays, due to possessing the features of wide gamut and real color expression. However, most PeLEDs are made from polycrystalline perovskite films that contain a high concentration of defects, including point and extended imperfections. Reducing and mitigating non-radiative recombination defects in perovskite materials are still crucial prerequisites for achieving high performance in light-emitting applications.

Stabilizing γ-CsPbI Perovskite via Phenylethylammonium for Efficient Solar Cells with Open-Circuit Voltage over 1.3 V.

Cesium lead iodide (CsPbI ) perovskite has gained great attention due to its potential thermal stability and appropriate bandgap (≈1.73 eV) for tandem cells. However, the moisture-induced thermodynamically unstable phase and large open-circuit voltage (V ) deficit and also the low efficiency seriously limit its further development.

Large cation ethylammonium incorporated perovskite for efficient and spectra stable blue light-emitting diodes.

Perovskite light-emitting diodes (PeLEDs) have showed significant progress in recent years; the external quantum efficiency (EQE) of electroluminescence in green and red regions has exceeded 20%, but the efficiency in blue lags far behind. Here, a large cation CHCHNH is added in PEA(CsPbBr)PbBr perovskite to decrease the Pb-Br orbit coupling and increase the bandgap for blue emission. X-ray diffraction and nuclear magnetic resonance results confirmed that the EA has successfully replaced Cs cations to form PEA(CsEAPbBr)PbBr.

Cesium Lead Inorganic Solar Cell with Efficiency beyond 18% via Reduced Charge Recombination.

Cesium-based inorganic perovskite solar cells (PSCs) are promising due to their potential for improving device stability. However, the power conversion efficiency of the inorganic PSCs is still low compared with the hybrid PSCs due to the large open-circuit voltage (V ) loss possibly caused by charge recombination. The use of an insulated shunt-blocking layer lithium fluoride on electron transport layer SnO for better energy level alignment with the conduction band minimum of the CsPbI Br and also for interface defect passivation is reported.

Effects of Organic Cations on the Structure and Performance of Quasi-Two-Dimensional Perovskite-Based Light-Emitting Diodes.

Quasi-two-dimensional (quasi-2D) perovskites are efficient luminescent materials due to their self-assembled quantum-well structure. We found that the organic cations have a significant effect on the structure and performance of quasi-2D perovskite-based light-emitting diodes (LEDs). Two classic organic cations, formamidinium (FA) and methylammonium (MA), were chosen for investigation.

Synergistic improvement of perovskite film quality for efficient solar cells via multiple chloride salt additives.

Perovskite crystal film quality is critical for obtaining efficient perovskite solar cells. Anti-solvent processing was used for fast crystallization of perovskite precursor film, which can form dense perovskite film. However, the crystals from this method are usually small due to the fast crystal growth process, which could lead to grain boundary recombination.

Solvent-controlled growth of inorganic perovskite films in dry environment for efficient and stable solar cells.

Inorganic halide perovskites such as cesium lead halide are promising due to their excellent thermal stability. Cesium lead iodide (CsPbI) has a bandgap of 1.73 eV and is very suitable for making efficient tandem solar cells, either with low-bandgap perovskite or silicon.

Author Correction: Efficient green light-emitting diodes based on quasi-two-dimensional composition and phase engineered perovskite with surface passivation.

The original version of this Article omitted an acknowledgement to the source of Fig. 1a. The following has been added to the end of the caption to Fig.

Efficient green light-emitting diodes based on quasi-two-dimensional composition and phase engineered perovskite with surface passivation.

Perovskite light-emitting diodes (LEDs) are attracting great attention due to their efficient and narrow emission. Quasi-two-dimensional perovskites with Ruddlesden-Popper-type layered structures can enlarge exciton binding energy and confine charge carriers and are considered good candidate materials for efficient LEDs. However, these materials usually contain a mixture of phases and the phase impurity could cause low emission efficiency.

Planar-Structure Perovskite Solar Cells with Efficiency beyond 21.

Low temperature solution processed planar-structure perovskite solar cells gain great attention recently, while their power conversions are still lower than that of high temperature mesoporous counterpart. Previous reports are mainly focused on perovskite morphology control and interface engineering to improve performance. Here, this study systematically investigates the effect of precise stoichiometry, especially the PbI contents on device performance including efficiency, hysteresis and stability.