Critical role of additive-induced molecular interaction on the operational stability of perovskite light-emitting diodes

•Interfacial reactions accelerate the degradation of perovskites and devices•Dicarboxylic-acid-induced amidation prohibits interfacial reactions•Alkaline zinc oxide substrates catalyze process•Perovskite light-emitting diodes with notably improved stability are achieved Metal halide emerging as promising emitters for high-performance because their superior optical electrical properties. Despite rapidly efficiencies, state-of-the-art devices demonstrate poor stability, hindering commercialization. Functional additives have been widely used to achieve high device efficiency; however, there is a lack understanding additives’ role on operational stability. Here, we different molecular interactions induced by diamines dicarboxylic acids effects Although two types molecules show similar effectiveness in reducing defects perovskites, convert reactive organic ingredients stable amides, which prohibit detrimental between charge injection layers, leading greatly resulting devices. rapid improvements efficiency brightness perovskite (PeLEDs), remains critical challenge practical applications. high-efficiency PeLEDs, enabled incorporating into precursor depositions. We reveal that efficiently eliminate emissive layers through an situ process, catalyzed alkaline substrate. The formed amides layer underneath, stabilizing contacts ensuring excellent PeLEDs. Through rationally optimizing reaction efficient PeLEDs peak external quantum 18.6% long half-life time 682 h at 20 mA cm−2, presenting important breakthrough Low-cost, solution-processed metal possess tunable band gap, photoluminescence (PL) efficiency, color purity, making them candidates achieving cost-effective (LEDs).1Tan Z.K. Moghaddam R.S. Lai M.L. Docampo P. Higler R. Deschler F. Price M. Sadhanala A. Pazos L.M. Credgington D. et al.Bright based organometal perovskite.Nat. Nanotechnol. 2014; 9: 687-692Crossref PubMed Scopus (2732) Google Scholar, 2Wang N. Cheng L. Ge Zhang S. Miao Y. Zou W. Yi C. Sun Cao Yang al.Perovskite self-organized multiple wells.Nat. Photonics. 2016; 10: 699-704Crossref (1060) 3Quan L.N. Rand B.P. Friend R.H. Mhaisalkar S.G. Lee T.W. Sargent E.H. Perovskites next-generation sources.Chem. Rev. 2019; 119: 7444-7477Crossref (270) 4Liu X.K. Xu Bai Jin Wang J. Gao diodes.Nat. Mater. 2021; 20: 10-21Crossref (136) 5Zhao X. 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Engl. 59: 4099-4105Crossref (55) 24Wang Zhou Deng Rudd Moran Huang Efficient via enhancement.Nat. 5633Crossref (132) These additives, designed chemical structures terminal moieties, help reduce or improve crystallinity, yields (PL QYs) layers.6Cao Scholar,14Wu Scholar,16Yang Scholar,20Pan Scholar,23Wu Scholar,25Yuan al.Unveiling synergistic effect stoichiometry 2818Crossref (61) enhancing it largely unknown how these affect fabricated literature exhibit significantly even comparable characteristics.6Cao Scholar,17Wang Taking (NIR) formamidinium (FA)-based example, diamine-based measured (T50, taken radiance drop 50% its initial value) less than 10 under mild driving current density (20 cm−2);25Yuan contrast, amino acid-based this value increases around (100 cm−2).6Cao results imply general roles stability; importance guide further improvement In work, systematically investigated treated consisting representative carboxyl groups uncover additive-induced interaction—a factor previously neglected—on focused our study benchmark lead iodide (FAPbI3) incorporation acids. observed perovskites; dicarboxylic-acid-treated longer those diamine-treated ones. film crystallization, substrate underneath. bottom interlayer, improves contacts, judiciously engineering EQE measure outstandingly T50 represents remarkable commonly structure indium-doped tin (ITO)/zinc (ZnO)/polyethylenimine ethoxylated (PEIE)/FAPbI3 perovskite/poly (9,9-dioctyl-fluorene-co-N-(4-butylphenyl)diphenyl-amine) (TFB)/Au (Figure 1A).6Cao deposited FAPbI3 spin coating solutions containing (PbI2):formamidinium (FAI):molecule additive molar ratio 1:2:x (the optimized x varies molecule additives). chose bidentate 2,2′-(ethylenedioxy) diethylamine (EDEA) adipic acid (AAC), weights carbon atoms but i.e., (inset Figure 1B). EDEA (denoted EDEA-PeLEDs) following optimal procedures developed previous work.7Xu For AAC AAC-PeLEDs), deposition conditions = 0.5 S1). present statistics control (without any additive), EDEA- AAC-PeLEDs 1B. exhibited average 7%, results.7Xu either (x 0.3) 0.5) 17%. All three identical electroluminescence (EL) spectra emission locating 802 nm 1C), consistent from three-dimensional (3D) perovskites. 3D also confirmed X-ray diffraction (XRD) results, shows no detectable low-dimensional impurity phases AAC-based S2A). addition, 119 W sr−1 m−2 225 286 AAC-PeLEDs, respectively S3). provide versus (EQE-J) density-voltage-radiance (J-V-R) curves Figures 1D 1E, respectively, champion AAC-PeLEDs. Both 18%, low sub-band-gap turn-on voltages (defined voltage needed reaching 0.1 m−2) below 1.5 V 200 m−2. Similar EDEA-PeLEDs demonstrated work,7Xu ascribe mainly reduced evidenced increased PL lifetime S4A) obviously QYs excitation densities S4B) compared films. (and same negligible change absorption spectrum) comparison S2B). island features S2C) might enhance due outcoupling,6Cao outcoupling itself would not such significant 7% 17% parameters, strikingly As shown 1F, typical demonstrates 26.5 constant cm−2 corresponding 17 m−2, report.7Xu order fair devices, all work fixing output level (around m−2). Impressively, exhibits radiance, delivering 178.9 h, 6 times EDEA-PeLEDs. started assessing thermal understand reasons behind dramatically Joule heating elevated temperature operation was regarded affecting stability.4Liu carried out stress treatments 100°C glovebox. 2A, both EDEA-based showed obvious fading stress, implying layers. XRD 2B 2C confirm decomposition phase transition showing gradually increasing peaks PbI2 yellow non-perovskite after 30 min stress. On contrary, exhibiting 2A) almost main 2D) whole period 300 min. Given arguably one factors deteriorating PeLEDs,26Zhao Roh Kacmoli Al Kurdi Jhulki Barlow Marder S.R. 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Academic Press, 1991Google evidence films, process rationalized excess grains. key monitoring evolution 2F 2G, decreased characteristics 100°C, indicating continuous loss cations.