Molecularly engineered low-dimensional hybrid perovskites are demonstrated as anode materials for alkali-ion batteries. The electrochemical performance can be dramatically improved by tuning the dimensionality of halide-perovskites from 3D to 2D to 1D.

The present solid state lighting (SSL) technology is based on using a combination of phosphors to give the desired white light emitting devices. The property of broadband emission from a single phosphor is not only difficult to achieve but also poses a challenge in device fabrication. Hybrid organic–inorganic perovskites especially in low dimensions (2D/1D) are being widely explored for their optoelectronic properties. Few of these materials exhibit broadband emission upon ultraviolet excitation, providing a scope for synthetic engineering in achieving commercially viable single‐phosphor materials. In this work, three interesting diammonium‐based low‐dimensional hybrid perovskites for broadband photoluminescence (PL) are examined. The doubly protonated ethylenediamine‐configured monoclinic (P21/n) 1D ribbon assembly (H3NCH2CH2NH3)8(Pb4Br18) · Br6 (1) and the orthorhombic (Pbcm) 2D‐twisted octahedral (H3NCH2CH2NH3)(Pb2Cl6) (2) show white luminescence, while the doubly protonated piperazine‐configured orthorhombic (Pnnm) 0D dual‐octahedral (C4N2H12)4(Pb2Br11) · (Br)(H2O)4 (3) exhibits bluish‐white luminescence. Based on the PL of the organic diammonium salt, the time‐resolved PL, Raman signatures, and density functional theory (DFT) calculations, it is shown that the broadband luminescence has dual origin: one around 400 nm from diammonium‐related molecular fluorescence and another around 516 nm from self‐trapped excitons. The structure‐specific relative contributions and interplay between the two define the overall character of the broadband luminescence.

COMMUNICATION (1 of 8)this family of materials including high absorption coefficients, [6] low energetic disorder, [7,8] high photoluminescence quantum yields (PLQYs), [9] long diffusion lengths for carriers, [10,11] and easy bandgap tunability [12][13][14][15] give many opportunities for further development. Owing to their high PLQYs, luminescence-based applications of perovskites including LEDs [4,13,14,[16][17][18][19][20] and lasers [9,21,22] are now receiving attention. Methylammonium lead tribromide (MAPbBr 3 ) has been shown to demonstrate efficient performance in LEDs when used as an emissive layer. [23][24][25] Moreover, this material possesses relatively high exciton binding energy (>25 meV) compared to MAPbI 3 perovskite and demonstrates greater air stability. [17,26,27] There are various routes of obtaining high semiconductor quality and ideal morphology of perovskite thin films by making minor modifications in single step spin coating and two step deposition processes along with other supramolecular passivation methods. [28][29][30][31][32] Recently, Cho et al. demonstrated high LED efficiencies by altering crystallization of MAPbBr 3 perovskite during spin coating process resulting in small but highly luminescent nanograin morphology. [4] However, use of such solution processed methods to enhance the PLQYs is less studied. We here demonstrate a novel additive mediated solvent engineering method to form highly luminescent perovskite thin films with superior semiconductor quality. Post treatment, we observe a significant enhancement in PLQYs and PL decay lifetimes in the MAPbBr 3 thin films. We performed detailed structural and photophysical studies using X-ray diffraction (XRD), UV-visible spectroscopy (UV-vis), time resolved photoluminescence, and photothermal deflection spectroscopy (PDS) techniques to understand these subtle changes upon the treatment. Furthermore, we demonstrate efficient LEDs using the treated perovskite layer as an emissive layer.Complete coverage of perovskite thin films on any substrate is a primary requirement for fabricating any optoelectronic device and many attempts have been made to achieve this. [28,31,[33][34][35] Fabricating perovskites using lead (II) acetate Significant enhancement in the luminescence and superior photophysical properties of CH 3 NH 3 PbBr 3 thin films prepared via simple single step spin coating process involving a novel additive mediated solvent extraction step isreported. This process results in significantly lower disorder in CH 3 NH 3 PbBr 3 perovskites with Urbach energies reducing from ≈35 to ≈17 meV, which is the lowest reported value to date. The additive mediated process also results in a remarkable improvement in the photoluminescence quantum yields (PLQYs) from 1% to 30%. Coupled with the overall increase in surface roughness, a significant increase in the internal PLQY from 7% to 77% is estimated, indicating the superior quality of the treated thin films. The resultant high quality CH 3 NH 3 PbBr 3 perovskites with remarkable photophysi...