The Past, Present, and Future of Metal Halide Perovskite Light‐Emitting Diodes

Abstract

Metal halide perovskites (MHPs) have emerged as new‐generation highly efficient narrow‐band luminescent materials with applications in various optoelectronic devices, including photovoltaics (PVs), light‐emitting diodes (LEDs), lasers, and scintillators. Since the demonstration of efficient room‐temperature electroluminescence from MHPs in 2014, remarkable progress has been achieved in the development and study of light‐emitting MHP materials and devices. While the device efficiencies of MHP LEDs (PeLEDs) have significantly improved over a short period of time, their overall performance has not reached the levels of mature technologies yet, such as organic LEDs (OLEDs) and quantum dot LEDs (QDLEDs), to enable practical applications. Many issues and challenges, including low operational stability, lack of efficient blue PeLEDs, and toxicity of MHPs, remain to be addressed. Herein, some of the most exciting progress achieved in the development of efficient and stable PeLEDs during the last few years are introduced, the main issues and challenges in the field are discussed, and the prospects on addressing these issues and challenges are provided. With continuous effort, the potential of PeLEDs to become a commercially available LED technology for display and lighting applications in the future looks optimistic.

Dendritic CsSnI3 for Efficient and Flexible Near‐Infrared Perovskite Light‐Emitting Diodes

“…[5] External quantum efficiencies (EQEs) of the leadbased perovskite light-emitting diodes (Pero-LEDs) have all exceeded 20% for the green, [6][7][8] red, [9] and red/near-infrared (NIR) [10][11][12][13] emitting ones, which shows great potential in lighting and colorful display. [14][15][16][17][18] However, the lead toxicity issue has become an enormous obstacle lying on the way to commercialization. [19] To overcome this problem, scientists have developed diverse lead-free MHPs, including equal divalent metal cations (such as Sn 2+ ), [20][21][22] double perovskites using two metal cations (mono valent and trivalent cations, such as Ag + and Bi 3+ ), [23] and some perovskite variants using single monovalent (such as Cu + ) [24] or trivalent (such as Sb 3+ ) [25] metal cations.…”

Promoting Energy Transfer via Manipulation of Crystallization Kinetics of Quasi‐2D Perovskites for Efficient Green Light‐Emitting Diodes

“…Metal halide perovskites are an emerging family of materials for light-emitting application owing to their high tolerance of defects, high color purity (narrow fullwidth at half-maximum of emission peak), tunable bandgap, and solution processibility. [1][2][3][4][5] The external quantum efficiency (EQE) of green and near-infrared perovskite light-emitting diodes (PeLEDs) has exceeded 20%, suggesting their great potential toward commercialization. [6][7][8][9] However, in typical 3D perovskite, the low exciton binding energy and long carrier diffusion length make non-radiative recombination outcompete radiative recombination, especially at low exciting density, limiting the electroluminescence efficiency.…”

Interfacial “Anchoring Effect” Enables Efficient Large‐Area Sky‐Blue Perovskite Light‐Emitting Diodes

“…Perovskite light‐emitting diodes (PeLEDs) are emerging as a promising candidate for the applications of high‐quality full‐color displays due to their tunable emissions, high color purity, and simple solution processability. [ 1 , 2 , 3 , 4 , 5 ] In recent years, great breakthroughs have been witnessed in external quantum efficiencies (EQEs), which exceed 20% with emission colors ranging from green to near‐infrared. [ 6 , 7 , 8 ] However, as one of the primary‐color devices, the performance of blue PeLEDs still lags far behind from the other counterparts in terms of device efficiency and operational stability.…”