Bright light-emitting diodes based on organometal halide perovskite

Abstract

Solid-state light-emitting devices based on direct-bandgap semiconductors have, over the past two decades, been utilized as energy-efficient sources of lighting. However, fabrication of these devices typically relies on expensive high-temperature and high-vacuum processes, rendering them uneconomical for use in large-area displays. Here, we report high-brightness light-emitting diodes based on solution-processed organometal halide perovskites. We demonstrate electroluminescence in the near-infrared, green and red by tuning the halide compositions in the perovskite. In our infrared device, a thin 15 nm layer of CH3NH3PbI(3-x)Cl(x) perovskite emitter is sandwiched between larger-bandgap titanium dioxide (TiO2) and poly(9,9'-dioctylfluorene) (F8) layers, effectively confining electrons and holes in the perovskite layer for radiative recombination. We report an infrared radiance of 13.2 W sr(-1) m(-2) at a current density of 363 mA cm(-2), with highest external and internal quantum efficiencies of 0.76% and 3.4%, respectively. In our green light-emitting device with an ITO/PEDOT:PSS/CH3NH3PbBr3/F8/Ca/Ag structure, we achieved a luminance of 364 cd m(-2) at a current density of 123 mA cm(-2), giving external and internal quantum efficiencies of 0.1% and 0.4%, respectively. We show, using photoluminescence studies, that radiative bimolecular recombination is dominant at higher excitation densities. Hence, the quantum efficiencies of the perovskite light-emitting diodes increase at higher current densities. This demonstration of effective perovskite electroluminescence offers scope for developing this unique class of materials into efficient and colour-tunable light emitters for low-cost display, lighting and optical communication applications.

Coherent Spin and Quasiparticle Dynamics in Solution‐Processed Layered 2D Lead Halide Perovskites

“…Halide perovskites are in the limelight due to their outstanding optoelectronic properties for photovoltaics1 and light emitting diodes (LEDs) 2, 3, 4. Layered 2D halide perovskites, comprising of alternating organic and inorganic layers, is one subcategory within this family of hybrid materials.…”

Control of Interface Defects for Efficient and Stable Quasi‐2D Perovskite Light‐Emitting Diodes Using Nickel Oxide Hole Injection Layer

“…Metal halide perovskites (MHPs) have emerged as a promising class of materials for optically pumped lasers and light‐emitting diodes (LEDs) owing to their narrow emission spectrum and wide range of color tunability 1, 2, 3, 4, 5, 6, 7. To date, perovskite LEDs (PeLEDs) have recorded an external quantum efficiency (EQE) of up to 14.36% for green emissions6 and 12.7% for near‐infrared emissions 7.…”

Local Versus Long‐Range Diffusion Effects of Photoexcited States on Radiative Recombination in Organic–Inorganic Lead Halide Perovskites

“…These two materials were chosen due to their use in photovoltaic cells2, 17, 18, 19 (CH 3 NH 3 PbI 3 ) and light‐emitting diodes8 (CH 3 NH 3 PbBr 3 ). We employ scanning near‐field optical microscopy (SNOM), which has been previously used to study local PL variations in nanostructured systems like polymer thin films,20 inorganic quantum structures,21 and polymer blends 22, 23.…”