solar cells, and organic light emitting diodes. Because their perovskite precursors are commercially available, the study of PSCs has recently become an important emerging scientific field. [1] Today, the critical issues for PSC development are related to increasing their performance and stability. [2] Because the short-circuit current densities (J sc ) of PSC devices have almost approached their theoretical limit, efforts directed toward further increasing the performance have been based on increasing their open-circuit voltages (V oc ) and fill factors (FFs). Such approaches will necessitate optimizing the morphology, the interfacial layers, the device architectures, and the hole/electron transporting layers. [3] With advances in device engineering and materials, the power conversion efficiencies (PCEs) of PSCs have skyrocketed from 3.8% to 22.7% within the last six years. [1e,f,3c,4] Efforts at optimizing the morphologies of PSC films (i.e., their grain size, coverage, and crystallinity) have directly led to greater PSC performance. For example, variations in the solvents, thermal engineering techniques, and additives have all played roles in improving the quality of the resulting perovskite films. [5] Many types of additives-including metal/organic halide salts, solvents, Lewis bases, [6] inorganic acids, polymers, [7] and fullerenes-can enhance the morphologies and efficiencies of PSCs. [8] Considering the complexity of perovskite formation, the vast array of fabrication parameters, and the myriad materials that can be involved in the process, there remains plenty of room for new discoveries in this field.Because perovskite films are generally prepared through solution processes, the presence of defects-ones that cause nonradiative energy loss and decrease the values of V oc and efficiencies-is unavoidable. Tuning the composition to passivate the defects of perovskites (using such materials as pyridine [9] and polymers [8a] ) can be an efficient means of improving the performance of PSCs. In this present study, we employed carbon nanodots (CNDs) as additives that efficiently tailor the optoelectronic properties of perovskites. Because of their nanoscale dimensions, tunable optoelectronic properties, and ready synthesis (to present various functional groups), the study of CNDs has experienced rapid development, especially for Carbonized bamboo-derived carbon nanodots (CNDs) as efficient additives for application in perovskite solar cells (PSCs) are reported. These carboxylic acid-and hydroxyl-rich CNDs interact with the perovskite through hydrogen bonds and, thereby, promote the carriers' lifetimes and realize high-performance p-i-n PSCs having the structure indium tin oxide/ NiO x /CH 3 NH 3 PbI 3 (MAPbI 3 )/PC 61 BM/BCP/Ag. As a result of interactions between the CNDs and the perovskite, the presence of the nonvolatile CND additive increases the power conversion efficiency (PCE) of the PSC from 14.48% ± 0.39% to 16.47% ± 0.26%. Furthermore, adding urea, a Lewis base, increases the PCE to 20.2%-the re...

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Microstructure, crystal structure, and magnetic properties of the Fe49–xCoxPt51 (x = 0, 0.7, 1.3, 2.2) thin films deposited on glass substrates were investigated. The addition of Co was found to enhance the magnetization of the FePt L l0 phase, thus increases the energy product, (BH)max. A maximum value of (BH)max of 18.4 MGOe was obtained in the sample with x = 1.3 annealing at 500 °C. The microstructure results indicated that significant grain refining was found in the x = 2.2 sample, which reduced from averagely 60 nm for the x = 0.0∼1.3 sample to 30 nm. The concentration of Co was uniform in the Fe‐Pt‐Co film except x = 1.3 film, in which small grains with 10∼20 nm in diameter showed higher percentage of Co. Corresponding to the compositional inhomogeneity, X‐ray structural analysis revealed that the x = 1.3 film contained about 20 vol.% disordered fcc phase, which was much higher than the other composition samples (<7 vol.%). The exchanging coupling between the ordered and disordered phase can explain the enhanced magnetic properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

In article number https://doi.org/10.1002/aenm.201802323, Chih‐Ping Chen and co‐workers demonstrate hydrophilic carbon nanodots efficient additives in perovskite solar cells (PSC). The p‐i‐n PSC device incorporating these additives demonstrated a power conversion efficiency of 20.2% and exhibited excellent air‐stability, maintaining high PCEs (25 °C and a humidity of 40%) for over 500 h.