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Abstract Electrically driven light‐emitting diodes (ED LEDs) based on 3D metal halide perovskites have seen remarkable advancements during the past decade. However, the highest‐performing devices are largely based on lead‐containing 3D perovskites, presenting two key challenges – toxicity and stability – that must be addressed for commercialization. Reducing structural dimensionality and incorporating non‐lead metals present promising pathways to address these issues. Although research on ED LEDs based on low‐dimensional, lead‐free metal halides (LD LFMHs) is growing, their performance still significantly lags behind that of 3D lead halide perovskites. This review seeks to deliver a comprehensive overview of ED LEDs based on LD LFMHs, covering a brief history of their development, methods for material synthesis, luminescence mechanisms, and applications in electroluminescent devices. It also examines current challenges and proposes practical strategies to enhance device performance, with the goal of inspiring further progress in the field. 

Abstract Metal halide perovskites and perovskite‐related organic metal halide hybrids (OMHHs) have recently emerged as a new class of luminescent materials for light emitting diodes (LEDs), owing to their unique and remarkable properties, including near‐unity photoluminescence quantum efficiencies, highly tunable emission colors, and low temperature solution processing. While substantial progress has been made in developing monochromatic LEDs with electroluminescence across blue, green, red, and near‐infrared regions, achieving highly efficient and stable white electroluminescence from a single LED remains a challenging and under‐explored area. Here, a facile approach to generating white electroluminescence is reported by combining narrow sky‐blue emission from metal halide perovskites and broadband orange/red emission from zero‐dimensional (0D) OMHHs. For the proof of concept, utilizing TPPcarz⁺passivated two‐dimensional (2D) CsPbBr₃nanoplatelets (NPLs) as sky blue emitter and 0D TPPcarzSbBr₄as orange/red emitter (TPPcarz⁺= triphenyl (9‐phenyl‐9H‐carbazol‐3‐yl) phosphonium), white LEDs (WLEDs) with a solution processed bilayer structure have been fabricated to exhibit a peak external quantum efficiency (EQE) of 4.8% and luminance of 1507 cd m⁻²at the Commission Internationale de L'Eclairage (CIE) coordinate of (0.32, 0.35). This work opens a new pathway for creating highly efficient and stable WLEDs using metal halide perovskites and related materials. 

Abstract Zero‐dimensional (0D) organic metal halide hybrids (OMHHs) have recently emerged as a new class of light emitting materials with exceptional color tunability. While near‐unity photoluminescence quantum efficiencies (PLQEs) are routinely obtained for a large number of 0D OMHHs, it remains challenging to apply them as emitter for electrically driven light emitting diodes (LEDs), largely due to the low conductivity of wide bandgap organic cations. Here, the development of a new OMHH, triphenyl(9‐phenyl‐9H‐carbazol‐3‐yl) phosphonium antimony bromide (TPPcarzSbBr₄), as emitter for efficient LEDs, which consists of semiconducting organic cations (TPPcarz⁺) and light emitting antimony bromide anions (Sb₂Br₈²⁻), is reported. By replacing one of the phenyl groups in a well‐known tetraphenylphosphonium cation (TPP⁺) with an electroactive phenylcarbazole group, a semiconducting TPPcarz⁺cation is developed for the preparation of red emitting 0D TPPcarzSbBr₄single crystals with a high PLQE of 93.8%. With solution processed TPPcarzSbBr₄thin films (PLQE of 86.1%) as light emitting layer, red LEDs are fabricated to exhibit an external quantum efficiency (EQE) of 5.12%, a peak luminance of 5957 cd m⁻², and a current efficiency of 14.2 cd A⁻¹, which are the best values reported to date for electroluminescence devices based on 0D OMHHs. 

Light emitting diodes (LEDs) have wide applications from fullcolor displays to solid‐state lighting. Numerous types of luminescent materials have been explored for LEDs, ranging from inorganic semiconductors to metal complexes and quantum dots. Despite the rapid pace of development, LEDs have not achieved their full potentials in terms of performance and cost efficiency. Identifying new eco‐friendly materials for LEDs is of great interest. Recently, metal halide perovskites and perovskite‐related hybrid materials have emerged as new generation luminescent materials with unique optoelectronic properties. Here, some of our recent development of LEDs based on metal halide perovskites and perovskite‐related materials will be discussed.