Exciton many-body interaction is the fundamental light–matter that determines optical response of new class colloidal perovskite nanocrystals general formula CsPbX3 [X = Cl, Br, or I]. However, understanding exciton interactions manifested through transient biexcitonic Stark effect at early time scales and Auger recombination process in this materials still remains rather incomplete. In Article, we studied under controlled conditions ultrafast absorption spectroscopy. A large redshift ∼30...

Abstract Herein we report the colloidal synthesis of Cs 3 Sb 2 I 9 and Rb perovskite nanocrystals, explore their potential for optoelectronic applications. Different morphologies, such as nanoplatelets nanorods , spherical nanocrystals were prepared. All these samples show band‐edge emissions in yellow–red region. Exciton many‐body interactions studied by femtosecond transient absorption spectroscopy reveals characteristic second‐derivative‐type spectral features, suggesting red‐shifted...

Two-dimensional (2D) covalent organic frameworks (COFs) are an emerging class of porous materials with potential for wide-ranging applications. Intense research efforts have been directed at tuning the structure and topology COF, however bandgap engineering COF has received less attention, although it is a necessary step developing material photovoltaic or photonic Herein, we developed approach to narrow COFs by pairing triphenylamine salicylideneaniline building units construct eclipsed...

Defect-tolerant perovskite nanocrystals of the general formula Cs-Pb-${X}_{3}$ (where $X=\mathrm{Cl}$, Br, and I) have shown exceptional potential in fundamental physics as well novel optoelectronic applications next generation solar cells. Although exciton many-body interactions such biexciton Stark shift, state filling, Auger recombination are studied extensively, other important correlated effects, band gap renormalization (BGR) hot-phonon bottleneck, not explored these nanocrystals. Here...

Noble metal nanoclusters protected with carboranes, a 12-vertex, nearly icosahedral boron-carbon framework system, have received immense attention due to their different physicochemical properties. We synthesized ortho-carborane-1,2-dithiol (CBDT) and triphenylphosphine (TPP) coprotected [Ag42(CBDT)15(TPP)4]2- (shortly Ag42) using ligand-exchange induced structural transformation reaction starting from [Ag18H16(TPP)10]2+ Ag18). The formation of Ag42 was confirmed UV-vis absorption...

Hot carrier extraction is crucial for efficient solar energy harvesting, and lead halide perovskite nanocrystals (NCs) are potential candidates photovoltaic light-emitting applications. Therefore, swift of hot carriers an immediate requirement to improve the conversion efficiency, which need longer thermalization time. To address this issue, we synthesized nominally Cu-doped CsPbI3 NCs with enhanced structural optical characteristics compared undoped NCs. We investigated dynamics in both at...

Extended ligand conjugation enhances luminescent thermometry in dinuclear Dy-SMMs, improving thermometric properties and enabling rare direct energy transfer from the ligands' singlet state to Dy( iii ), as shown by excited-state lifetime.

Multiple carrier generation (MCG), a process wherein two or more carriers are generated from single high-energy absorbed photon, holds immense promise for quantum sensing, metrology, low-threshold lasers, and photovoltaics. Despite its potential, MCG has faced obstacles such as low efficiency high threshold photon energy at least twice the band gap (2Eg) of semiconductor, limiting application only to class materials with Eg. Here, we present new approach that overcomes this limitation by...

We report the synthesis of [Ag17(o1-CBT)12]3- abbreviated as Ag17, a stable 8e⁻ anionic cluster with unique Ag@Ag12@Ag4 core-shell structure, where o1-CBT is ortho-carborane-1-thiol. By substituting Ag atoms Au and/or Cu at specific sites we created isostructural clusters [AuAg16(o1-CBT)12]3- (AuAg16), [Ag13Cu4(o1-CBT)12]3- (Ag13Cu4) and [AuAg12Cu4(o1-CBT)12]3- (AuAg12Cu4). These substitutions make systematic modulation their structural electronic properties. show that preferentially...

Colloidal Ag2S nanocrystals (NCs) typically do not exhibit sharp excitonic absorption and emission. We first elucidate the reason behind this problem by preparing NCs from nearly monodisperse CdS employing cation exchange reaction. It was found that defect-related midgap transitions overlap with transition, blurring spectrum. On basis of observation, we prepared defect-free using molecular precursors. These absorption, emission (quantum yield 20%) in near-infrared (853 nm) region, improved...

A complex few-layer $\mathrm{MoS}{\mathrm{e}}_{2}$/graphene oxide (GO) heterostructure with strong interlayer coupling was prepared by a facile hydrothermal method. In this strongly coupled heterostructure, we demonstrate giant enhancement of two-photon absorption that is in stark contrast to the reverse saturable weakly $\mathrm{MoS}{\mathrm{e}}_{2}$/GO and isolated $\mathrm{MoS}{\mathrm{e}}_{2}$. Spectroscopic evidence our study indicates optical signatures $\mathrm{MoS}{\mathrm{e}}_{2}$...

Auger recombination and thermalization time are detrimental in reducing the gain threshold of optically pumped semiconductor nanocrystal (NC) lasers for future on-chip nanophotonic devices. Here, we report design strategy facet engineering to reduce amplified spontaneous emission by manyfold NCs same concentration edge length. We achieved this hallmark result controlling rates dominated processes involving NC volume emitting states optimizing number facets from 6 (cube) 12 (rhombic...

Superfluorescence, a cooperative coherent spontaneous emission, is of great importance to the understanding many-body correlation in optical processes. Even though superfluorescence has been demonstrated many diverse systems, it hard observe electron-hole plasma (EHP) due its rapid dephasing and hence needs strong magnetic fields or complex microcavities. Herein, we report first experimental observation from EHP up moderate temperature 175 K without external stimuli coupled metal halide...

Chiral hybrid metal halide perovskites provide hopes of combining chirality induced by the organic sublattice with optoelectronic properties arising from inorganic sublattice. The field is still in its infancy, material space mainly focused on two-dimensional lead perovskites. Here we report a zero-dimensional Pb-free perovskite derivative structure chemical composition [(R-/S-MBA)4Bi2I10], where MBA stands for methylbenzylammonium. Single-crystal X-ray diffraction data show that...

Nonresonant optical driving of confined semiconductors can open up exciting opportunities for experimentally realizing strongly interacting photon-dressed (Floquet) states through the Stark effect (OSE) coherent modulation exciton state. Here we report first room-temperature observation Floquet biexciton-mediated anomalous excitonic OSE in CsPbBr3 quantum dots (QDs). Remarkably, strong exciton-biexciton interaction leads to a red shift and splitting resonance as function drive photon...

Transformation chemistry of atomically precise metal nanoclusters has emerged as a novel strategy for fundamental research on the structure-property correlations nanomaterials. However, thorough understanding transformation mechanism is indeed necessary to understand structural growth patterns and corresponding property evolutions in nanoclusters. Herein, we present ligand-exchange-induced [Au23(SR)16]- (8e-) nanocluster [Au25(SR')18]- nanocluster, through Au23(SR)17 (6e-) intermediate...

Superfluorescence, a coherent burst of light from an excited ensemble emitters, is crucial quantum optical phenomenon with far-reaching implications in nanophotonics and many-body processes. Despite its observation various systems, realizing superfluorescence electron-hole plasma (EHP) at room temperature has remained formidable challenge, hindering the development continuous-wave electrically devices. Herein, we address this challenge by condensing high-density EHP into liquid (EHL)...

Nonlinear optical absorption of light by materials are weak due to its perturbative nature, although a strong nonlinear response is crucial importance applications in limiting and switching. Here we demonstrate experimentally theoretically an extremely efficient scheme excited state charge transfer between donor acceptor as the new method enhance orders magnitude. With this idea, have demonstrated (ESA) reduced graphene oxide that otherwise shows increased transparency at high fluence...

Cu2BaSnS4 (CBTS) is an emerging earth-abundant and environmentally benign semiconductor. However, there has been no prior report of colloidal CBTS nanocrystals. Here we developed a synthesis nanocrystals by rational design. Photophysical properties these are elucidated using photoluminescence ultrafast transient absorption spectroscopy. Finally, thin films grown at room temperature used as the hole transport layer (HTL) in organic photodiode yielding high peak specific detectivity (>3.2 ×...

Superstructures made by assemblies of metal nanoclusters (NCs) have gained interest due to their atomic precision and exciting photophysical properties. Although there are some reports cluster-assembled materials NCs protected with thiols, the preparation stable thiol-free analogs is largely unexplored poor stability such structures. Herein, we report synthesis phosphine-protected alloy silver varying gold doping superstructures systems. We show that alloying clusters results in...

We experimentally demonstrate the coexistence of two opposite photo-effects, viz. fast photodarkening (PD) and slow photobleaching (PB) in Ge19As21Se60 thin films, when illuminated with a laser wavelength 671nm, PD appears to begin instantaneously upon light illumination saturates tens seconds. By comparison, PB is slower process that starts only after has saturated. Although we could observe PD/PB even at moderate, one order magnitude lower intensity 0.2 W/cm2, kinetics transformation...

In this letter, we have investigated the third-order optical nonlinearities of high-quality Ni doped ZnO nanorods crystallized in wurtzite lattice, prepared by wet chemical method. our experiments, found that two photon absorption coefficient (β) increases as much 14 times, i.e., 7.6 ± 0.4 to 112 6 cm/GW, when doping is increased from 0% 10%. The substantial enhancement β discussed terms bandgap scaling and doping. Furthermore, also show measured UV-Vis photoluminescence spectroscopies,...

One-dimensional (1D) free-standing nanowires are particularly important for carrier confinement in two dimensions, which provides a platform to explore the nonlinear optical phenomena at nanoscale. In this Letter, we demonstrate saturable absorption resonant and above-bandgap excitations of both ns fs pulses 1D crystalline Sb2Se3 prepared by facile hydrothermal method. Impressively, average length extends few micrometers with high aspect ratio 300. The excited-state ground-state...