Halide Perovskite Thin Film Lasing Mode Control.

Metal halide perovskite semiconductors have emerged as highly efficient amplifying materials; to ensure practical applicability, it is important to have precise control over the spectral and polarization characteristics of lasing emission. In this study, we present effective strategies for manipulating single- and multimode lasing from surface-emitting and optically pumped perovskite distributed feedback lasers. We show that cladding structures can be made to modify the optical properties of guided transverse electric and magnetic modes within the gain medium.

Toward Nonepitaxial Laser Diodes.

Thin-film organic, colloidal quantum dot, and metal halide perovskite semiconductors are all being pursued in the quest for a wavelength-tunable diode laser technology that does not require epitaxial growth on a traditional semiconductor substrate. Despite promising demonstrations of efficient light-emitting diodes and low-threshold optically pumped lasing in each case, there are still fundamental and practical barriers that must be overcome to reliably achieve injection lasing. This review outlines the historical development and recent advances of each material system on the path to a diode laser.

Hot-Casting-Assisted Liquid Additive Engineering for Efficient and Stable Perovskite Solar Cells.

High-performance inorganic-organic lead halide perovskite solar cells (PSCs) are often fabricated with a liquid additive such as dimethyl sulfoxide (DMSO), which retards crystallization and reduces roughness and pinholes in the perovskite layers. However, DMSO can be trapped during perovskite film formation and induce voids and undesired reaction byproducts upon later processing steps. Here, it is shown that the amount of residual DMSO can be reduced in as-spin-coated films significantly through use of preheated substrates, or a so-called hot-casting method.

Nanosecond-Pulsed Perovskite Light-Emitting Diodes at High Current Density.

While metal-halide perovskite light-emitting diodes (PeLEDs) hold the potential for a new generation of display and lighting technology, their slow operation speed and response time limit their application scope. Here, high-speed PeLEDs driven by nanosecond electrical pulses with a rise time of 1.2 ns are reported with a maximum radiance of approximately 480 kW sr  m at 8.

Thermal Management Enables Bright and Stable Perovskite Light-Emitting Diodes.

The performance of lead-halide perovskite light-emitting diodes (LEDs) has increased rapidly in recent years. However, most reports feature devices operated at relatively small current densities (<500 mA cm ) with moderate radiance (<400 W sr m ). Here, Joule heating and inefficient thermal dissipation are shown to be major obstacles toward high radiance and long lifetime.

Mixed Lead-Tin Halide Perovskites for Efficient and Wavelength-Tunable Near-Infrared Light-Emitting Diodes.

Near-infrared (NIR) light-emitting diodes (LEDs), with emission wavelengths between 800 and 950 nm, are useful for various applications, e.g., night-vision devices, optical communication, and medical treatments.

Hybrid perovskite light emitting diodes under intense electrical excitation.

Hybrid perovskite semiconductors represent a promising platform for color-tunable light emitting diodes (LEDs) and lasers; however, the behavior of these materials under the intense electrical excitation required for electrically-pumped lasing remains unexplored. Here, we investigate methylammonium lead iodide-based perovskite LEDs under short pulsed drive at current densities up to 620 A cm. At low current density (J < 10 A cm), we find that the external quantum efficiency (EQE) depends strongly on the time-averaged history of the pulse train and show that this curiosity is associated with slow ion movement that changes the internal field distribution and trap density in the device.

Improved Outcoupling Efficiency and Stability of Perovskite Light-Emitting Diodes using Thin Emitting Layers.

Hybrid organic-inorganic perovskite semiconductors have shown potential to develop into a new generation of light-emitting diode (LED) technology. Herein, an important design principle for perovskite LEDs is elucidated regarding optimal perovskite thickness. Adopting a thin perovskite layer in the range of 35-40 nm is shown to be critical for both device efficiency and stability improvements.

A Photonic Crystal Laser from Solution Based Organo-Lead Iodide Perovskite Thin Films.

Perovskite semiconductors are actively investigated for high performance solar cells. Their large optical absorption coefficient and facile solution-based, low-temperature synthesis of thin films make perovskites also a candidate for light-emitting devices across the visible and near-infrared. Specific to their potential as optical gain medium for lasers, early work has demonstrated amplified spontaneous emission and lasing at attractively low thresholds of photoexcitation.

Surface-emitting red, green, and blue colloidal quantum dot distributed feedback lasers.

We demonstrate surface emitting distributed feedback (DFB) lasers across the red, green, and blue from densely packed colloidal quantum dot (CQD) films. The solid CQD films were deposited on periodic grating patterns to enable 2nd-order DFB lasing action at mere 120, 280, and 330 μJ/cm2 of optical pumping energy densities for red, green, and blue DFB lasers, respectively. The lasers operated in single mode operation with less than 1 nm of full-width-half-maximum.