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The search for efficient, re-absorption-free scintillators has recently focused the attention on antimony-based halides, which exhibit largely Stokes shifted luminescence due to radiative recombination of excitons self-trapped (STE) in strongly Jahn-Teller distorted Sb3+ color centers. Here, the synthesis of a hybrid structure is reported with chemical formula (C13H14N3)3SbCl6 consisting of spatially isolated [SbCl6]3- octahedra separated by organic N, N'-diphenylguanidinium (Gua) molecules. The optical properties of this material are mainly determined by the inorganic component and are characterized by a pronounced Stokes shift of "1.3 eV and a room-temperature photoluminescence (PL) efficiency of up to 85%. Remarkably, highly efficient radioluminescence (RL) is observed with scintillation light yields of "2000 ph MeV-1 using both soft X-rays and a 124 keV gamma source. Temperature-dependent PL and RL measurements confirm the minor role of non-radiative channels, which are completely suppressed below 100 K. Thermally stimulated luminescence measurements suggest that the traps in Gua3SbCl6 crystals have a significantly large energy depth distribution below the absorbing state. [ABSTRACT FROM AUTHOR]

Here, cation exchange (CE) reactions are exploited to radiolabel ZnSe, ZnS, and CuFeS2 metal chalcogenide nanocrystals (NCs) with 64Cu. The CE protocol requires one simple step, to mix the water‐soluble NCs with a 64Cu solution, in the presence of vitamin C used to reduce Cu(II) to Cu(I). Given the quantitative cation replacement on the NCs, a high radiochemical yield, up to 99%, is reached. Also, provided that there is no free 64Cu, no purification step is needed, making the protocol easily translatable to the clinic. A unique aspect of the approach is the achievement of an unprecedentedly high specific activity: by exploiting a volumetric CE, the strategy enables to concentrate a large dose of 64Cu (18.5 MBq) in a small NC dose (0.18 µg), reaching a specific activity of 103 TBq g−1. Finally, the characteristic dielectric resonance peak, still present for the radiolabeled 64Cu:CuFeS2 NCs after the partial‐CE reaction, enables the generation of heat under clinical laser exposure (1 W cm−2). The synergic toxicity of photo‐ablation and 64Cu ionization is here proven on glioblastoma and epidermoid carcinoma tumor cells, while no intrinsic cytotoxicity is seen from the NC dose employed for these dual experiments. [ABSTRACT FROM AUTHOR]

The integration of colloidal nanocrystals with polymers adds optoelectronic functionalities to flexible and mechanically robust organic films. In particular, self-assembled structures of nanocrystals in polymers can act as functional components enhancing, for instance, transport or optical properties of the hybrid material. This study presents Cu2Te hexagonal nanodisks that assemble into ribbons with a face-to-face configuration in poly(3-hexylthiophene-2,5-diyl) through a controlled solvent evaporation process. The ribbons form weaving patterns that create 3D networks fully embedded in the thin polymer film at high nanodisk concentration. The photoresponse of these composite films measured in a layered vertical geometry demonstrates increased photocurrent with increasing nanocrystal loading. This study attributes this behavior to the presence of networks of Cu2Te nanodisks that form a bulk heterojunction with the semiconducting polymer, which improves exciton dissociation and the overall photoelectric response. [ABSTRACT FROM AUTHOR]

Absorbing near‐infrared (NIR) photons, with longer wavelengths, in atomically thin monolayer MoS2 presents a significant challenge due to its weak optical absorption and narrow absorption bands. Consequently, MoS2‐based photodetector devices often experience low responsivity and a limited detection window. Herein, a novel InAs@ZnSe core@shell/1L‐MoS2 heterostructure, leveraging InAs@ZnSe as the primary infrared‐absorbing material and exploiting the formation of a type‐II heterostructure is showcased. Steady‐state and time‐resolved spectroscopy, along with optoelectronic characterization, are employed to investigate photo‐induced charge transfer dynamics. The results show efficient hole transfer to InAs@ZnSe upon excitation of both materials. Instead, with selective excitation of InAs@ZnSe, electron transfer is observed from InAs@ZnSe to the 1L‐MoS2. The heterostructure demonstrates a broadband photoresponse spanning the wavelength range of 300 to 850 nm, exhibiting a Responsivity of ≈103 A/W and Detectivity of ≈1011 Jones. The signal‐to‐noise ratio substantially increases by 3 to 4 orders of magnitude for 700 and 850 nm excitation compared to pristine 1L‐MoS2. The enhancement in photoresponse and signal‐to‐noise ratio is attributed to increased absorption, which helps eliminate defect and trap states, thereby promoting the photogating effect. [ABSTRACT FROM AUTHOR]

Lead halide perovskite nanocrystals (LHP NCs) are generally prone to surface defect formation during the purification process, resulting in a reduced photoluminescence (PL) quantum yield. The purification of LHP NCs using antisolvents leads to the detachment of surface atoms and ligandsin the form of alkylammonium‐halides or A‐carboxylates (A: Cs, methylammonium, MA, or formamidinium, FA. Currently, intense research is being carried out to improve the surface stability of LHP NCs using various long‐chain organic ligands that strongly bind to the surface of NCs. Herein, the findings on the higher surface stability of hybrid (MAPbBr3 and FAPbBr3) LHP NCs compared to that of inorganic CsPbBr3 NCs against purification with polar antisolvents are reported. It is discovered that the CsPbBr3 NC surface stability can be enhanced (reaching that of hybrid perovskite NCs) by the incorporation of a small amount of MA or FA A‐site organic cations into their lattice, corroborated by the evidence that the PL quantum yield of mixed A‐cation CsxFA1‐xPbBr3 and CsxMA1‐xPbBr3 NCs remains unaffected after several purification cycles. It is hypothesized that this is attributed to hydrogen bonding between the organic A‐site cations and the neighboring halides on the surface. These findings are not only fundamentally important but are also expected to have wide implications in the field of metal‐halide perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

Excitonic 0D and 2D lead‐halide perovskites have been recently developed and investigated as new materials for light generation. Here broadband (>1 eV) emission from newly synthesized 0D lead‐free colloidal Cs3Bi2I9 nanocrystals (NCs) is reported. The nature of their emissive states as well as the relative dynamics which are currently hotly debated are investigated. In particular, it is found that the broadband emission is made by the coexistence of emissive excitons and sub‐bandgap emissive trap‐states. Remarkably, evidence of enhanced Raman scattering from the ligands is observed when attached to the NCs surface, an effect that is preliminarily attributed to strong exciton‐ligands electronic coupling in these systems. [ABSTRACT FROM AUTHOR]