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Although organic-inorganic halide perovskite solar cells (PSCs) have shown dramatically enhanced power conversion efficiencies (PCEs) in the last decade, their long-term stability is still a critical challenge for commercialization. To address this issue, tremendous research efforts have been devoted to exploring all-inorganic PSCs because of their intrinsically high structural stability. Among them, CsPbIBr 2 -based all-inorganic PSCs have drawn increasing attention owing to their suitable band gap and favorable stability. However, the PCEs of CsPbIBr 2 -based PSCs are still far from those of their organic-inorganic counterparts, thus inhibiting their practical applications. Herein, we demonstrate that by simply doping an appropriate amount of Cu 2+ into a CsPbIBr 2 perovskite lattice (0.5 at. % to Pb 2+ ), the perovskite crystallinity and grain size are increased, the perovskite film morphology is improved, the energy level alignment is optimized, and the trap density and charge recombination are reduced. As a consequence, a decent PCE improvement from 7.81 to 10.4% is achieved along with an enhancement ratio of 33% with a CsPbIBr 2 -based PSC. Furthermore, the long-term stability of CsPbIBr 2 -based PSCs against moisture and heat also remarkably improved by Cu 2+ doping. This work provides a facile and effective route to improve the PCE and long-term stability of CsPbIBr 2 -based all-inorganic PSCs.

Removal of toxic organics and bacterial disinfection are important tasks in wastewater treatment. Most heavy metal-based catalysts for degradation of aqueous organic pollutants in heterogeneous Fenton-like processes suffer from the toxicity of leached metals. The present work reports environmentally benign systems for both degradation of organics and bacterial disinfection. Calcium substituted LaFeO 3- δ perovskite was demonstrated as an efficient catalyst to activate peroxymonosulfate (PMS) for degradation of phenol, methylene blue and rhodamine 6 G. Compared to LaFeO 3- δ and nanocrystal Fe 3 O 4 , the lattice oxygen vacancies in B-site cation-deficient perovskite of La 0.8 Ca 0.2 Fe 0.94 O 3 - δ (LaCaFeO 3- δ ) particles renders this material a greatly improved catalytic performance. Electron paramagnetic resonance (EPR) suggested that both sulfate (SO 4 -) and hydroxyl radicals (OH) played critical roles in the advanced oxidation processes. Moreover, silver doped perovskite (Ag-LaCaFeO 3- δ )/PMS successfully inhibited the growth of waterborne pathogen Escherichia coli and Methicillin-resistant Staphylococcus aureus (MRSA) at a lower dose than silver ions, proving a synergetic effect between free radicals and Ag + in killing the bacteria. Therefore, Ag-LaCaFeO 3- δ /PMS would be promising for practical wastewater treatment., (Copyright © 2018 Elsevier B.V. All rights reserved.)