Organic−inorganic lead halide perovskite solar cells are potential alternatives to commercial silicon solar cells because of their attractive photon conversion efficiency and general material costs, except for the widely adopted organic hole-transporting polymers, which are currently expensive and have low conductivity. Inorganic hole-transporting layers (HTLs) have recently garnered attention due to their excellent stability and relatively effective cost. Nickel oxide (NiO x ) is a typical p-type oxide semiconductor with a deep valence band (VB) and is expected to be used as HTL. Unfortunately, the charge extraction efficiency has been hindered by its poor conductivity, resulting in lower efficiency when compared with organic HTL-based devices. Here, we report a new solutionprocessed doping strategy for NiO x with zinc dopant to improve its conductivity for perovskite solar cells. The NiO x :Zn HTL showed high transparency and significantly enhanced electrical conductivity in comparison with the pristine NiO x . Our best NiO x :Zn-based P-i-N planar device showed an efficiency of 19.6% with negligible hysteresis, which is comparable with the reported planar solar cell with an organic HTL. Moreover, the NiO x :Zn-based perovskite device displayed distinguished stability in ambient conditions. This paper demonstrated important progress toward high-efficiency planar perovskite devices with low-cost inorganic HTLs.

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The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202107252. Suitable anode materials with high capacityand long cycling stability, especially capability at high current densities, are urgently needed to advance the development of potassium ion batteries (PIBs) and sodium ion batteries (SIBs). Herein, a porous Ni-doped FeSe 2 /Fe 3 Se 4 heterojunction encapsulated in Se-doped carbon (NF 11 S/C) is designed through selenization of MOFs precursor. The porous composite possesses enriched active sites and facilitates transport for both ion and electron. Ni-doping is adopted to enrich the lattice defects and active sites. The Se-C bond and carbon framework endow integrity of the composite and hamper aggregation of selenide nano-particles during potassiation/de-potassiation. The NF 11 S/C exhibits exceptional rate performance and ultra-long cycling stability (177.3 mA h g −1 after 3050 cycles at 2 A g −1 for PIBs and 208.8 mA h g −1 after 2000 cycles at 8 A g −1 for SIBs). The potassiation/de-potassiation mechanism is investigated via ex-situ X-ray powder diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectrocopy and Raman analysis. PTCDA//NF 11 S/C full cell stably cycles for 1200 cycles at 200 mA g −1 with a capacity of 103.7 mA h g −1 , indicating the high application potential of the electrode for highly stable rechargeable batteries.

Metal sulfides are promising anodes for potassium-ion batteries (PIBs) due to their high theoretical capacity and abundant active sites; however, their intrinsic low conductivity and poor cycling stability hampered their practical applications. Given this, the rational design of hybrid structures with high stability and fast charge transfer is a critical approach. Herein, CoS 2 /ZnS@ rGO hybrid nanocomposites were demonstrated with stable cubic phases. The synergistic effect of the obtained bimetallic sulfide nanoparticles and highly conductive 2D rGO nanosheets facilitated excellent long-term cyclability for potassium ion storage. Such hybrid nanocomposites delivered remarkable ultrastable cycling performances in PIBs of 159, 106, and 80 mA h g −1 at 1, 1.5, and 2 A g −1 after 1800, 2100, and 3000 cycles, respectively. Moreover, the fullcell configuration with a perylene tetracarboxylic dianhydride organic cathode (CoS 2 /ZnS@rGO∥PTCDA) exhibited a better electrochemical performance. Besides, when the CoS 2 /ZnS@rGO nanocomposites were applied as an anode for sodium-ion batteries, the electrode demonstrated a reversible charge capacity of 259 mA h g −1 after 600 cycles at 2 A g −1 . In situ X-ray diffraction and ex situ high-resolution transmission electron microscopy characterizations further confirmed the conversion reactions of CoS 2 /ZnS during insertion/ desertion processes. Our synthesis strategy is also a general route to other bimetallic sulfide hybrid nanocomposites. This strategy opens up a new roadmap for exploring hybrid nanocomposites with feasible phase engineering for achieving excellent electrochemical performances in energy storage applications.

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Inverted perovskite solar cells have received huge attention due to their exceptional photovoltaic performance, yet they are susceptible to hysteresis and low conductivity. Poly 3,4-ethylenedioxythiophene: Poly 4-styrenesulfonate (PEDOT: PSS) is...