Colloidal CsPbBr3 perovskite nanocrystals (NCs) have emerged as an excellent light emitting material in last one year. Using time domain and time-resolved THz spectroscopy density functional theory based calculations, we establish 3-fold free carrier recombination mechanism, namely, nonradiative Auger, bimolecular electron–hole recombination, inefficient trap-assisted 11 nm sized colloidal NCs. Our results confirm a negligible influence of surface defects trapping charge carriers, which turn...

Understanding the nature of chemical bonding and lattice dynamics together with their influence on phonon-transport is essential to explore design crystalline solids ultralow thermal conductivity for various applications including thermoelectrics. TlInTe2, interlocked rigid weakly bound substructures, exhibits as low ca. 0.5 W/mK near room temperature, owing rattling Tl cations. Large displacements cations along c-axis, driven by electrostatic repulsion between localized electron clouds Te...

Structural non-centrosymmetry in semiconducting organic-inorganic hybrid halide perovskites can introduce functionalities like anomalous photovoltaics and nonlinear optical properties. Here we a design principle to prepare Pb- Bi-based two- one-dimensional with polar non-centrosymmetric space groups. The relies on creating dissimilar hydrogen halogen bonding non-covalent interactions at the interface. For example, organic cations I-(CH2)3-NH2(CH3)+ (MIPA), -CH3 is substituted by -CH2I one...

Abstract Optoelectronically active hybrid lead halide perovskites dissociate in water. To prevent this dissociation, here, we introduce long‐range intermolecular cation‐π interactions between A‐site cations of perovskites. An aromatic diamine like 4,4′‐trimethylenedipyridine, if protonated, can show a stacking, and therefore, serves as our cation. Consequently, 4,4′‐trimethylenedipyridinium bromide [(4,4′‐TMDP)Pb 2 Br 6 ], one‐dimensional perovskite, remains completely stable after...

Understanding the mechanism that correlates phonon transport with chemical bonding and solid-state structure is key to envisage develop materials ultralow thermal conductivity, which are essential for efficient thermoelectrics barrier coatings. We synthesized thallium selenide (TlSe), comprised of intertwined stiff weakly bonded substructures exhibits intrinsically lattice conductivity (κL) 0.62-0.4 W/mK in range 295-525 K. Ultralow κL TlSe a result its low energy optical modes strongly...

We present results on terahertz (THz) spectroscopy epitaxial vanadium dioxide (VO2) films grown sapphire across the metal-insulator transition. X-ray diffraction indicates VO2 film is highly oriented with crystallographic relationship: (002)film//(0006)sub and [010]film//[21¯1¯0]sub. THz studies measuring change in transmission as a function of temperature demonstrate an 85% reduction thin completes its phase transition to conducting phase, which much greater than previous observation...

Colloidal all inorganic CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) have emerged to be an excellent material for applications in light emission, photovoltaics, and photocatalysis. Efficient interfacial transfer of photogenerated electrons holes are essential a good photovoltaic photocatalytic material. Using time-resolved terahertz spectroscopy, we measured the kinetics electron hole processes CsPbBr3 NCs presence benzoquinone phenothiazine molecules as acceptors, respectively. hot...

Ice and solid H2S look as different pears oranges, leading Pauling to conclude that H2O has hydrogen bonds van der Waals interactions. Now it is shown the dimer, like indeed hydrogen-bonded. As a service our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed may be re-organized for online delivery, but not copy-edited or typeset. Technical support issues arising from (other than missing files) should addressed Please note: The...

This research article explores the distinct TADF efficiency of three donor-acceptor based regio-isomers: DPAOCN (ortho-isomer), DPAMCN (meta-isomer), and DPAPCN (para-isomer). exhibits maximum in both solution solid-state with an impressive reverse inter-system crossing (RISC) rate ∼106 s-1; underlying cause being minimum singlet-triplet splitting energy or ΔEST SOC (spin-orbit coupling) between S1 & T1 states. Apart from TADF, differences crystal packing regio-isomers result intriguing bulk...

Recently, we defined 'hydrogen-bond radii' for various hydrogen-bond donors, DH where D = F, Cl, Br, CN, HO or CCH from an empirical analysis. It was shown that the A⋯H distances in B⋯HD complexes could be written as a sum of hydrogen bond radius and constant acceptor A, which is bonding atom/centre B. This manuscript reports determination radii these molecules H2S ab initio atoms (AIM) theoretical calculations. The results calculations are consistent with estimates six noted above provide...

This work reports that ligand engineering can modulate the triplet harvesting mechanism in iodide-bridged rhombic Cu2I2 complexes. Complex-1, with a smaller Cu-Cu distance, exhibits phosphorescence from 3(M+X)LCT and 3CC states 66% quantum yield, whereas an increased distance complex-2 results switch of emission to TADF, which occurs via 1/3(M+X)LCT 83% yield. The TADF property has been utilized for fabrication pc-LED emitting efficient warm white light. Moreover, high charge-transfer nature...

Organic-inorganic hybrid metal halides have become enormously important in optoelectronics, sensing, photosensitization, etc. In this study, we report a structural transition from staircase configuration to cubane Cu(I) iodide-based polymers influenced by the coordination behavior of two different π*-acceptor ligands. The polymer structure, coordinated with 3-cyanopyridine, demonstrates efficient thermally activated delayed fluorescence (metal+halide)-to-ligand charge transfer [1/3(M+X)LCT]...

Chiral hybrid metal halides show great promise for nonlinear optical (NLO) applications like circularly polarized second harmonic generation (SHG). The inherent toxicity of lead is a concern the widespread adoption frequently explored lead-based chiral halides. Here, we report and third-order NLO properties lead-free 0D compounds, (R-/S-MBA)4Bi2I10, their achiral counterpart, (Rac-MBA)4Bi2I10 (MBA: methylbenzylammonium) under excitation wavelength ranging 1360-1590 nm. (R-/S-MBA)4Bi2I10...

Colloidal TlI and TlBr nanocrystals are prepared, which show violet-blue luminescence, high carrier mobility long diffusion lengths thus suggesting the suppression of deep-trap states.

The introduction of chirality in layered hybrid perovskites breaks the symmetry their inorganic sub-lattices. Consequently, they show intriguing linear and non-linear optical properties. Here we explore effect on excitonic photoluminescence chiral (R- S-α-MBA)2PbI4 (MBA: methylbenzylammonium) at cryogenic temperatures. induced splits emissions below 150 K. Additionally, wavelength-tunable second harmonic generation (SHG) that depends strongly polarization angle incident light.

Abstract Low‐dimensional lead‐halide perovskites show wide structural and compositional diversity. Multiple functionalities can be introduced in these materials for diverse linear nonlinear optical applications. Nonlinear (NLO) processes depend on material polarizability, crystal symmetry, processibility. The flexibility of choosing organic cations provides an opportunity enhanced NLO responses by enhancing the overall system polarizability. A highly polarizable diisopropylammonium [Dipa;...

Typically, bright excitons (XB) emit light in two-dimensional (2D) layered hybrid perovskites. There are also dark (XD), for which radiative recombination is spin-forbidden. Application of a magnetic field can somewhat relax the spin-rule, yielding XD emission. Can we obtain emission absence field? Indeed, observe unusually intense at ∼7 K (Rac-MBA)2PbI4, (Rac-4-Br-MBA)2PbI4, and (R-4-Br-MBA)2PbI4 (Rac-MBA: racemic methylbenzylammonium), crystallize lower symmetry monoclinic phase. For...

Hybrid lead halide perovskites have emerged as an important class of optoelectronic materials. A creative choice "A"-site organic cations produces hybrid with reduced dimensionality and intriguing light–matter interactions. Nonlinear optical effects are expected to be stronger in one-dimensional (1D) halides compared those their 2D or 3D analogues due greater quantum dielectric confinements. We performed extensive probe the third harmonic generation (THG) properties 1D pyridinium iodide...

Abstract The pulsed nozzle Fourier transform microwave (PNFTMW) spectrometer was developed by Balle and Flygare [A new method for observing the rotational spectra of weak molecular complexes: KrHCl. J. Chem. Phys. 1979, 71 (6), 2723–2724 1980, 72 (2), 922–932] in 1979. design, fabrication, operation this are complicated it has largely remained a research laboratory tool till now, though portable routine analytical applications been at National Institute Standards Technology [Suenram, R.D.;...

In this article, the effective size of hydrogen in halides forming bonded complexes is estimated. The scheme proposed by Bhadane and Gadre [J. Chem. Phys. 107, 5625 (1997)] for estimating HF extended to other (HCl HBr) HCN. It noted that radius H atom HF, HCl, HBr, HCN are, respectively, 0.55±0.07, 0.74±0.08, 0.80±0.11, 0.93±0.07 Å. radii found HBr show a strong inverse correlation with dipole moment HX. From HI estimated be 0.90±0.11 By extrapolating zero moment, van der Waals determined...

This work aims to experimentally determine the polarizability of confined electron in CdSe quantum dots (QD). The dielectric response uncharged and charged (3.2 6.3 nm) has been measured using terahertz time-domain spectroscopy frequency range 2.0−7.0 THz. A strong coupling between surface plasmon phonons appears upon charging QDs. absolute an 3.2 nm QDs are determined be 0.5 ± 0.1 × 103 Å3 14.6 0.3 Å3, respectively, values agree reasonably well with theory previous experiment. observed...

Population transfer between low-lying Rydberg states independent of the initial state is realized using a train half-cycle pulses with pulse durations much shorter than classical orbital period. We demonstrate experimentally population from around $n=50$ $10%$ de-excited down to $n<40$ as well up continuum. This demonstration state-independent de-excitation technique applicable currently produced distribution antihydrogen. The measured matches model process for one-dimensional atoms.

This paper reports the rotational spectrum and structure of Ar2–H2S complex its HDS D2S isotopomers. The ground state has heavy-atom C2v symmetry with two Ar atoms indistinguishable H2S freely rotating as evinced by fact that asymmetric top energy levels Kp = odd are missing. constants for parent isotopomer are: A 1733.115(1) MHz, B 1617.6160(5) MHz C 830.2951(2) MHz. Unlike Ar–H2S complex, does not show an anomalous isotopic shift in on deuterium substitution. However, intermolecular...