Efficient and bright broadband electroluminescence based on environmentfriendly metal halide nanoclusters

Broadband electroluminescence based on environment-friendly emitters is promising for healthy lighting yet remains an unprecedented challenge to progress.The copper halide-based emitters are competitive candidates for broadband emission,but their high-performance electroluminescence shows inadequate broad emission bandwidth of less than 90 nm.Here,we demonstrate efficient ultra-broadband electroluminescence from a copper halide(CuI)nanocluster single emitter prepared by a one-step solution synthesis-deposition process,through dedicated design of ligands and subtle selection of solvents.The CuI nanocluster exhibits high rigidity in the excitation state as well as dual-emissive modes of phosphorescence and temperature-activated delayed fluorescence,enabling the uniform cluster-composed film to show excellent stability and high photoluminescent efficiency.In consequence,ultra-broadband light-emitting diodes(LEDs)present nearly identical performance in an inert or air atmosphere without encapsulation and outstanding high-temperature operation performance,reaching an emission full width at half maximum(FWHM)of~120 nm,a peak external quantum efficiency of 13%,a record maximum luminance of~50,000 cd m^(−2),and an operating half-lifetime of 137 h at 100 cd m^(−2).The results highlight the potential of copper halide nanoclusters for next-generation healthy lighting.

双层膦氧化物分子修饰制备高效的大面积纯蓝光钙钛矿量子点发光二极管

蓝光卤素钙钛矿发光二极管(LED)由于其高色纯度和全色钙钛矿LED发展需求目前受到越来越多的关注.通过钝化卤素钙钛矿中的缺陷来提高LED性能是主要研究方向,然而,用于有效钝化混合卤素蓝光钙钛矿并获得性能优异、光谱稳定的纯蓝光LED方法还很有限.本文开发了一种使用含有膦氧基团的双层有机分子对混合卤素蓝光钙钛矿量子点进行固相修饰,不仅有效提高了量子点薄膜的发光性能,而且有效改善了LED的电荷平衡,显著提高了器件性能,获得了最大外量子效率为4.87%的纯蓝光LED(469 nm).作者发现双层膦氧分子与量子点之间可以发生强相互作用,从而有效钝化量子点,并有助于获得大面积单层钙钛矿量子点薄膜.其中,发光面积为64 mm2,波长为469 nm的LED最大外量子效率为3.91%.本文所述策略有助于推动性能优异的大面积钙钛矿量子点光电器件开发.