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Organic–inorganic copper(I) halides (OICHs) have recently attracted great attentions for their unique optoelectronic properties. However, most of them have poor stability and narrow excitation in UV region, which seriously hinder their applications in efficient white light‐emitting diodes (WLEDs). Herein, 0D (C19H18P)2Cu4I6 with super broad‐band excitation (300–500 nm) and yellow emission with the absolute photoluminescence quantum yield of 87.4% is synthesized in a quantity of gram scale. Specifically, (C19H18P)2Cu4I6 possesses exceptional thermal‐, photo‐, air‐stability, and can maintain efficient emission even if soaked in water, ethyl acetate, and isopropanol over 30 days. WLEDs with remarkable color stability under various driven currents are fabricated using 450, 400, 365, and 310 nm LED chips. The ideal WLEDs based on single (C19H18P)2Cu4I6 by 450 nm LED chip presents high color rendering index of 86.7, and outstanding luminous efficiency of 90 lm W−1. To the best of the knowledge, this is the highest value that is achieved based on single‐component OICHs using blue light chip. This work not only promotes the prospect of OICHs in WLEDs but also significantly broadens their application in special lighting fields, such as underwater illumination. [ABSTRACT FROM AUTHOR]

Lead‐free vacancy‐ordered double perovskites with formula of A2M(IV)X6 have become promising alternatives to lead halide perovskites. Herein, novel direct bandgap lead‐free vacancy‐ordered double perovskites Rb2ZrCl6−xBrx (0 ≤ x ≤ 2) with highest photoluminescence quantum yield (PLQY) of 90% are synthesized by using a facile wet grinding approach. Experimental and theoretical analyses demonstrate that the bright emissions originate from the self‐trapped excitons (STEs). Additionally, thermally activated delayed fluorescence (TADF) is observed in these perovskites, confirmed by temperature‐dependent steady‐state PL spectra and time‐resolved PL spectra measurements. The competitive equilibrium relationship is demonstrated further between the singlet STEs and the triplet STEs of Rb2ZrCl6−xBrx interrelated to temperature. Meanwhile, satisfying the Vegard's law, the optical bandgap of Rb2ZrCl6−xBrx decreases linearly from 3.895 to 3.778 eV with x increasing. Furthermore, density functional theory (DFT) calculations prove the highly localized electronic states generated in flat electronic bands of Rb2ZrCl6−xBrx, as evidence by the presence of self‐trapped state in [ZrCl6−xBrx]2− octahedra, and the energy level of the halogen 3p orbitals is the key factor that dictates their bandgaps. [ABSTRACT FROM AUTHOR]

Nanoscale laser arrays are attractive for their potential applications in highly integrated nanodevices, which are always obtained by nanowire arrays with complicated fabrication techniques. Here, a quite different nanolaser array is successfully realized based on a highly ordered core–shell CdS branched nanostructure with implanted Sn nanoparticles in junctions that split the individual multichannel nanostructures to various microcavities with effective light confinement and oscillation, thus to achieve a multipoint nanolaser array. Under the excitation of an ultraviolet laser, the strong band‐edge emission can be well reflected between Sn nanoparticles at junctions and effectively scattered into branch segments due to Sn nanoparticles existence in junctions, furthermore oscillating in various microcavities along trunks or branches to form multipoint lasing from Fabry‐Pérot (F‐P) mode with a quality factor up to 990 and the low threshold at around 3.78 MW cm−2. The corresponding fluorescent microscope images further demonstrate the formation of multipoint F‐P lasing at various segments. The theoretical simulation indicates that implanted Sn nanoparticles work as hot point to enhance the confinement of light around the Sn centers. The existence of surface plasmon from the Sn metal particles is further confirmed by the polarization dependent photoluminescence measurement. The results provide a new way to realize nanolaser arrays. [ABSTRACT FROM AUTHOR]