Materials, photophysics and device engineering of perovskite light-emitting diodes

Abstract

Here we provide a comprehensive review of a newly developed lighting technology based on metal halide perovskites (i.e. perovskite light-emitting diodes) encompassing the research endeavours into materials, photophysics and device engineering. At the outset we survey the basic perovskite structures and their various dimensions (namely three-, two- and zero-dimensional perovskites), and demonstrate how the compositional engineering of these structures affects the perovskite light-emitting properties. Next, we turn to the physics underpinning photo- and electroluminescence in these materials through their connection to the fundamental excited states, energy/charge transport processes and radiative and non-radiative decay mechanisms. In the remainder of the review, we focus on the engineering of perovskite light-emitting diodes, including the history of their development as well as an extensive analysis of contemporary strategies for boosting device performance. Key concepts include balancing the electron/hole injection, suppression of parasitic carrier losses, improvement of the photoluminescence quantum yield and enhancement of the light extraction. Overall, this review reflects the current paradigm for perovskite lighting, and is intended to serve as a foundation to materials and device scientists newly working in this field.

Impact of Cesium Concentration on Optoelectronic Properties of Metal Halide Perovskites

“…Metal halide perovskites attract considerable attention due to their remarkable properties revealing potential applications in optoelectronic devices such as solar cells [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], photodetectors [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], light emitting diodes [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. They have also been used for photocatalysts [ 35 ] and bioimaging [ 36 ].…”

Thermodynamics-Induced Injection Enhanced Deep-Blue Perovskite Quantum Dot LEDs

“…In general, the electronic characteristics of QDs are crucial to evaluate the charge injection capacity in PeLEDs. ,, To visually compare the interfacial dipoles that correspond to the vacuum level shift, the surface potential (SP) was directly probed using Kelvin probe force microscopy (KPFM) (Figure S4). Here, high-mobility poly­( N , N ′-bis-4-butylphenyl- N , N ′-bisphenyl)­benzidine (poly-TPD) was used as a hole transport layer in PeLEDs.…”

“…The solution-processable metal halide perovskite quantum dots (QDs) have been intensively explored as promising active materials for the commercial application of large-area and low-cost perovskite light-emitting diodes (PeLEDs). − Among them, the external quantum efficiency (EQE) strides of near-infrared, red, and green PeLEDs have reached over 20%. , Nevertheless, as one of the three primary elements indispensable for display and lighting, blue PeLEDs still lag far behind their green and red counterparts in efficiency and stability, which immensely restricts the development of full-color PeLEDs. − …”

“…For example, a rubidium–cesium-alloyed “A-site” cation composition strategy could obtain spectra-stable blue PeLEDs, and energetic coupling by embedding quantum-confined nanoparticles into quasi-2D phases could also achieve blue electroluminescence (EL) . However, most quasi-2D PeLEDs concentrate on the sky-blue waveband. , To realize the pure-blue or bluer PeLEDs remains uninterruptedly challenging due to the rigorous requirement of a much lower-dimensional structure. , According to the standard of the National Television System Committee, blue emission below the EL of 470 nm is extremely requisite for a high-resolution display . The other to be a perovskite blue emitter is to employ the mixed chloride–bromide (Cl/Br) perovskites. − Easily tunable sky-to-deep blue emission spectra with intrinsically continuous band gap tailoring enabling this component-control strategy one of the most attractive approaches. ,− Unfortunately, phase segregation mediated by vacancy-induced ionic defects under the electric field would lead to poor efficiency and spectra instability. , Meanwhile, the balanced blue-emitting brightness is of vital importance to the lifetime and cost of the display panel when compared to relatively brighter red and green emission. , If overcoming field-induced instability and utilizing the easy-tuning advantages of spectra simultaneously, mixed halogen perovskites will be a highly competitive candidate to solve the backward situation of blue PeLEDs.…”

Multi-Pulse Terahertz Spectroscopy: Hot Polaron Photoconductivity Dynamics in Metal-Halide Perovskites

“…Metal-halide perovskites (MHPs) are the subject of intense optoelectronic research on account of their efficient light-absorbing and emitting characteristics, 1,2 composition-tunable bandgaps, 3 relatively high carrier mobilities 4,5 and surprisingly long carrier lifetimes/diffusion lengths. [6][7][8] These outstanding optical and electronic properties have prompted exhaustive investigations into the fundamental nature of the electronic excitations.…”