Cs3Cu2I5带隙

Cs3Cu2I5 has emerged as a prominent candidate for next-generation scintillators. To further enhance its scintillation performance, this study systematically investigated the electronic structure and optical properties of a series of doped Cs3Cu2I5 scintillators using density functional theory calculations. Cs3Cu2I5:Mn exhibits the narrowest bandgap due to the enlarged lattice constant as well as the influence of impurity levels to the conduction band minimum. By contrast, doping with In, Sn, Tl, and Zn slightly increases the bandgap of Cs3Cu2I5. At the meantime, the attenuation of scintillation light can be effectively suppressed by doping heteroatoms. As the amount of Mn2+ increases, the bandgap can be further reduced due to the electron delocalization. However, higher Mn2+ doping results in the confinement of electrons and causes a bandgap widening. Therefore, our findings can pave guidance for the rational designing of the doped Cs3Cu2I5 scintillator for high-energy radiation detection.

The metal halide Cs3Cu2I5 displays anomalous optical properties: an optical absorption onset in the ultraviolet region (∼ 330 nm) with highly efficient luminescence in the blue region (∼ 445 nm). Although self-trapped exciton formation has been proposed as the origin of giant Stokes shift, its connection to the photoluminescence quantum yield exceeding 90% remains unknown. Here, we explore the photochemistry of Cs3Cu2I5 from first-principles and reveal a low energy barrier for exciton self-trapping associated with Cu-Cu dimerization. Kinetic analysis shows that the quantum yield of blue emission in Cs3Cu2I5 is sensitive to the excited carrier density due to the competition between exciton self-trapping and band-to-band radiative recombination.

Low-dimensional copper halides with high luminance have attracted increasing interest as a heavy-metal free light emitter. However, the optical mechanisms underpinning their excellent luminescence remain underexplored. Here, we report multiple self-trapped emissions in Cs3Cu2I5. Power-dependent photoluminescence spectra reveal the appearance of multiple self-trapped emission peaks with increasing excitation power, and this emission behavior is explored across a temperature range of 80420 K. The 0D structure and soft crystal lattice contribute to the multiple self-trapped emissions in Cs3Cu2I5: this explains the origin of the broad emission and the luminescence mechanism in Cs3Cu2I5, and will assist in understanding the optical properties of other metal halides. We incorporate the Cs3Cu2I5 in light-emitting diodes (LEDs) that achieve a peak luminance of 140 cd/m2 and an external quantum efficiency of 0.27%.

Low-dimensional metal halide perovskites possessing a large exciton binding energy have shown great promise in achieving efficient photonic emission required in the fields of lighting sources and d...

The zero-dimensional copper halide perovskite Cs 3 Cu 2 I 5 displays extraordinary luminescence and scintillation characteristics, and high-quality crystals are extremely desirable for …

The unique combination of strong excitonic properties and environmental stability in 0D copper halide crystals motivates the development of scalable ambient fabrication routes for high‐quality emitters. Here, we report a low‐temperature solvent vapor‐assisted crystallization strategy to grow millimeter‐sized Cs3Cu2I5 crystals. Rb+ doping effectively passivates surface defects, markedly enhancing moisture and ambient stability, with the photoluminescence intensity remaining nearly unchanged after 60 days in air. Notably, the 10% Rb+‐doped crystals achieve a high photoluminescence quantum yield (PLQY) of 98.42%, demonstrating a pronounced emission enhancement. Ab initio molecular dynamics (AIMD) simulations reveal that both pristine and 10% Rb+‐doped structures reside in a similar energy window (−108 to −110 eV), while the doped system exhibits a more confined trajectory, suggesting a flattened energy landscape and suppressed defect formation. Doped lattice relaxations induce slight, direction‐dependent bond contraction, improving coordination integrity without major distortion, consistent with material stability and device reliability. By integrating blue‐emitting Cs3Cu2I5:10% Rb+ with green Cs3Cu2Cl5 and red CaAlSiN3:Eu2+, we fabricate high‐performance white light‐emitting diodes (WLEDs) achieving CRI of 95.36, CIE chromaticity coordinates of (0.30, 0.34), and outstanding luminance of 17734.5 cd/m2. These findings establish a versatile ambient pathway for defect‐engineered Cs3Cu2X5 (X = I, Cl) emitters, advancing their prospects for next‐generation solid‐state lighting technologies.

Abstract Silicon has been the most widely used material for broadband photodetectors. However, the weak response in ultraviolet (UV), especially in deep-UV region, and the large dark current are still their critical drawbacks for practical applications. In this study, a strategy of decorating Cs3Cu2I5 nanocrystals (NCs) on Si nanowire arrays (NWAs) to form a hybrid structure was proposed to overcome the above two issues. Because of the wide and direct bandgap of Cs3Cu2I5 with intrinsic UV light absorption, the photodetection ability of the hybrid detector in UV region was substantially enhanced owing to the efficient down-conversion of the UV incident light. Moreover, driven by a designed Schottky junction from asymmetric electrodes, the hybrid detector can be operated without external power supply. Typically, at 265 nm light excitation, the Si NWA-Cs3Cu2I5 NCs hybrid device achieved a high photoresponsivity of 83.6 mA W−1, a specific detectivity of 2.1×1012 Jones, and a large on/off ratio of 3.72×103 at 0 V, nearly 350 times higher than the bare Si NWA device. More importantly, the unencapsulated photodetector demonstrates an outstanding operational stability over the aging test for 10 h, and can endure a high humidity (75%, 7 days) and a long-term storage for 300 days in air ambient. Since the different deep-UV light sensitivity of the devices modified with/without Cs3Cu2I5 NCs, a monolithically deep-UV light recognition system was therefore fabricated. It is anticipated that the present strategy provides a new avenue for the preparation of UV-enhanced broadband photodetectors, opening up opportunities for development of integrated optoelectronic systems in the future.

High-quality Cs 3 Cu 2 I 5 :In single crystals with a 7 mm diameter were grown by using the vertical Bridgman method. These crystals have a high optical transmittance (>75 %) and emit …

… Recently, all-inorganic lead-free perovskite Cs 3 Cu 2 I 5 demonstrates great potential in ultraviolet detection for its outstanding long-term stability and suitable bandgap. Nevertheless, …

Cu-based halide perovskites arouse broad interest in optoelectronics because of the low toxicity and superb optical properties. However, the uniformity of phase purity and crystallite …

… Halide perovskite materials have attracted a large amount of attention due to their tuneable bandgap, high defect tolerance, high photoluminescence quantum yield (PLQY), and high …

Halide perovskites, including CsPbX3 (X = Cl, Br, I), have gained much attention in the field of optoelectronics. However, the toxicity of Pb and the low photoluminescence quantum yield (PLQY) of these perovskites hamper their use. In this work, new halide materials that meet the requirements of: (i) nontoxicity, (ii) high PLQY, and (iii) ease of fabrication of thin films via the solution process are explored. In particular, copper(I) halide compounds with low‐dimensional electronic structures are considered. Cs3Cu2I5 has a 0D photoactive site and exhibits blue emission (≈445 nm) with very high PLQYs of ≈90 and ≈60% for single crystals and thin films, respectively. The large exciton binding energy of ≈490 meV explains well the 0D electronic nature of Cs3Cu2I5. Blue electroluminescence of Pb‐free halides is demonstrated using solution‐derived Cs3Cu2I5 thin films.

Cs3Cu2I5 has been considered a promising lead‐free perovskite material for blue light emission due to its environmental friendliness and unique optical properties. Although Cs3Cu2I5 nanocrystals (NCs) exhibit excellent structural stability, their high specific surface area at the nanoscale inevitably leads to the formation of point defects caused by structural vacancies during the self‐assembling process. In this study, the Cs3Cu2I5 structure using pseudohalide thiocyanate (SCN⁻) is modified, which has an effective ionic radius similar to I⁻. The strong binding energy between Cu+ ions and the lone electron pairs of the S and N atoms in linear SCN⁻ ions enhance the crystallinity of the Cs3Cu2I5 NCs. In addition, the SCN⁻ ions improve size uniformity by adjusting the chemical potential in the solvent system. The SCN⁻ incorporation also modified the electronic structure of the Cs3Cu2I5 by changing the optical bandgap energy and improving the photoluminescence quantum yield from 62.5% to 76.7%. Finally, a fluorescent blue light‐emitting diode is demonstrated utilizing the excellent blue light emission, and white light emitting diode (white‐LED) are produced by combining this with a yellow‐emitting layer of CsCu2I3, exhibiting good operational stability.

Cs3Cu2I5 and CsCu2I3 with a low-dimensional electronic structure and strong electron–phonon coupling exhibit broad spectrum emission and high PLQY, which may originate from self-trapped exciton or excited-state structure reorganization.

Cs3Cu2I5 perovskite displays a Stokes-shifted photoluminescence (PL) at 445 nm, attributed to the self-trapped excitons (STEs). Unlike that observed in other perovskite materials, the free-exciton emission is not evidenced in this case. Herein, we reveal the existence of a short-lived high-energy emission centered around 375 nm through the reconstruction of time-resolved emission spectra (TRES), which is independent of the shape/size of Cs3Cu2I5 perovskite. This high-energy emission is proposed to originate from the free-exciton-derived distorted S1 state of the 0D Cs3Cu2I5 moiety. Moreover, STE PL (∼445 nm) was found to have phosphorescence characteristics. Theoretical calculation confirms a facile intersystem crossing at the Franck-Condon geometry, indicating the high lifetime of the STE and its triplet nature. The existence of a high-energy emissive state and the phosphorescent nature of the STE PL band provide valuable insights that could advance our understanding of the photophysics in these materials.

The lead-free copper-based halide perovskite Cs3Cu2I5 is a promising material that can overcome the toxicity and instability of lead-based halide perovskites, thereby affording remarkable performance in the field of optoelectronics. Cs3Cu2I5 perovskite exhibits blue emission with a very high photoluminescence quantum yield (PLQY). First-principles calculations were used herein to theoretically expound the origins of the high PLQY of Cs3Cu2I5: (i) the low symmetry of Cs3Cu2I5 breaks the forbidden transition and enables the transition process; (ii) the large transition matrix and high transition rate increase the probability for radiative recombination of Cs3Cu2I5; (iii) the good defect tolerance broadens the path for thermal relaxation and radiative recombination. The high transition rate and good defect tolerance account for the high-efficiency PLQY of the lead-free copper-based perovskite, Cs3Cu2I5.

… point, as shown in Figure 3a, with the conduction band minimum (CBM) lying at the gamma point. … In this condition, for a better description, we improved the k-point mesh in the Brillouin …

… 1b, which has a direct bandgap at Γ point. The calculated value of the bandgap width of Cs … At standard atmospheric pressure, the melting point of CuI and CsI is 605 and 621 C, …

… -dependent PL, time-resolved PL, and normalized PL/PLE confirm … with the optical properties, the specific photoluminescence … energy (E PL ) induced by STEs and the band gap E g and …

The copper‐based (Cu‐based) halide perovskite possesses eco‐friendly features, bright self‐trapped‐exciton (broadband) emission, and a high color‐rendering index (CRI) for achieving white emission. However, the limited hole injection (HI) of Cu‐based perovskites has been bottle‐necking the efficiency of white electroluminescence and thus their application in white perovskite light‐emitting diodes (W‐PeLEDs). In this study, we demonstrate a p‐type cuprous sulfide (Cu2S) lattice‐connectedly capping over Cs3Cu2I5 to form lattice‐matched core/shell nanocrystals (NCs) by controlling the reactivity of sulfur (S) precursor in the synthesis. Interestingly, the resultant Cs3Cu2I5/Cu2S NCs significantly enhance the hole mobility compared to Cs3Cu2I5 NCs. Besides, the photoluminescence quantum yield of Cs3Cu2I5 NCs increases from 26.8% to 70.6% after the Cu2S lattice‐connected capping. Consequently, by establishing the structure of CsCu2I3/Cs3Cu2I5/Cu2S in W‐PeLEDs, an external quantum efficiency of 3.45% and a CRI of 91 is realized, representing the highest reported electroluminescent performance in lead‐free Cu‐based W‐PeLEDs. These findings contribute to establishing guidelines and effective strategies for designing broadband electroluminescent materials and device structures of PeLEDs.

Lead-free copper halides have garnered significant attention due to their remarkable advancements in optoelectronic devices. While there have been numerous reports on the linear optical characteristics and device implementations for...

Lead-free copper-based halide perovskites, especially Cs 3 Cu 2 I 5 , represent promising alternatives to toxic lead-based materials because of their excellent optoelectronic properties. …

As a high‐interest emerging effect, negative thermal quenching (NTQ) may bring revolutionary advances in luminescence. However, the reason for NTQ is still unclear, making it challenging to target design materials with such unique properties. Interestingly, it is found that the Cs3Cu2I5 single‐crystals grown using the Bridgman and antisolvent methods exhibit the conventional thermal quenching, while the single‐crystal grown by the aqueous solution method yet has the NTQ. This suggests that a specific structural change in the single crystals can be induced to produce NTQ, harboring the secrets of NTQs. It is found that the Cs3Cu2I5 single‐crystal from the aqueous solution method has a more compact crystal structure, smaller Huang–Rhys factor, and a more considerable exciton binding energy than other methods. In this case, the structural distortion of Cs3Cu2I5 single‐crystal after photoexcitation is limited at low temperatures, and consequently, the self‐trapped exciton (STE) energy levels are incompletely formed. As the temperature increases, the STE energy levels gradually become fully formed, and their ability to trap electrons improves, resulting in the marvelous phenomenon of NTQ. This work provides a plausible mechanism for the mysterious NTQ and will guide the future design of NTQ materials.

… The photoluminescence (PL)/photoluminescence excitation (PLE) spectra of the thin films … The PL decay curves and PL lifetimes of the thin films were obtained a fluorescence lifetime …

… the band gap. The calculated optical bandgap was based on the onset of the optical … We subsequently analyzed its PLE and PL spectra at room temperature to gain deeper insights into …

0D lead-free metal halide nanocrystals (NCs) are an emerging class of materials with intriguing optical properties. Herein, colloidal synthetic routes are presented for the production of 0D Cs3 Cu2 X5 (X = I, Br, and Cl) NCs with orthorhombic structure and well-defined morphologies. All these Cs3 Cu2 X5 NCs exhibit broadband blue-green photoluminescence (PL) emissions in the range of 445-527 nm with large Stokes shifts, which are attributed to their intrinsic self-trapped exciton (STE) emission characteristics. The high PL quantum yield of 48.7% is obtained from Cs3 Cu2 Cl5 NCs, while Cs3 Cu2 I5 NCs exhibit considerable air stability over 45 days. Intriguingly, as X is changed from I to Br and Cl, Cs3 Cu2 X5 NCs exhibit a continuous redshift of emission peaks, which is contrary to the blueshift in CsPbX3 perovskite NCs.

All-inorganic cesium copper halide nanocrystals have attracted extensive attention due to their cost-effectiveness, low toxicity, and rich luminescence properties. However, controlling the synthesis of these nanocrystals to achieve a precise composition and high luminous efficiency remains a challenge that limits their future application. Herein, we report the effect of oleylammonium iodide on the synthesis of copper halide nanocrystals to control the composition and phase and modulate their photoluminescence (PL) quantum yields (QYs). For CsCu2I3, the PL peak is centered at 560 nm with a PLQY of 47.3%, while the PL peak of Cs3Cu2I5 is located at 440 nm with an unprecedently high PLQY of 95.3%. Furthermore, the intermediate-state CsCu2I3/Cs3Cu2I5 heterostructure shows white light emission with a PLQY of 66.4%, chromaticity coordinates of (0.3176, 0.3306), a high color rendering index (CRI) of 90, and a correlated color temperature (CCT) of 6234 K, indicating that it is promising for single-component white-light-emitting applications. The nanocrystals reported in this study have excellent luminescence properties, low toxicity, and superior stability, so they are more suitable for future light-emitting applications.

Low-dimensional metal halides are promising luminescent materials with efficient self-trapped exciton (STE) emission at room temperature; however, the understanding of optical behaviors and trends ...

… structure containing complex tetrameric cluster units that extend … that the Cs 3 Cu 2 I 5 -type Cs 3 Cu 2 Cl 5 (0D) can be … states around the bandgap are dominated by Cu orbitals, direct …

… exciton-phonon coupling and luminescence intensity remains incomplete. Herein, a doping-enhanced exciton-phonon coupling effect is observed in Cs3Cu2I5 … on these Cs3Cu2I5:AE …

Lead‐free zero‐dimensional (0D) metal halide perovskites have garnered considerable research interest owing to their pronounced self‐trapped exciton emission and exceptional stability. In this study, micron‐sized particulate Cs3Cu2I5 and Sb‐Cs3Cu2I5 are synthesized using the anti‐solvent method. For the first time, the broadband nonlinear optical properties of these materials in the near‐infrared region are systematically investigated. Compared to pristine Cs3Cu2I5, Sb‐Cs3Cu2I5 exhibited superior nonlinear optical performance, demonstrating a modulation depth of 17.7% and a nonlinear absorption coefficient of −(4.28 ± 0.05) cm MW−1 at 1 µm, as well as a modulation depth of 13.5% and a nonlinear absorption coefficient of −(3.25 ± 0.06) cm MW−1 at 1.5 µm. Capitalizing on its exceptional nonlinear optical response, Sb‐Cs3Cu2I5 is employed as a saturable absorber in both Yb‐doped and Er‐doped fiber lasers. In the Yb‐doped fiber laser, noise‐like pulse mode‐locking is achieved with a central wavelength of 1038.4 nm and a pulse width of 721 fs, while in the Er‐doped fiber laser, conventional soliton mode‐locking is realized with a central wavelength of 1557.7 nm and a pulse width of 853 fs. This work highlights the impact of Sb doping on the nonlinear optical features of Cs3Cu2I5, providing a novel design strategy for advanced nonlinear optical materials and applications in ultrafast photonic devices.

Low‐dimensional copper halides having nontoxic elements are attracting increasing attention for their peculiar emission properties. Self‐trapped excitons (STEs) account for their high photoluminescence quantum yields (PLQYs) with emission that can stretch across the entire visible spectrum. However, intrinsic factors that influence the formation or loss of the emissive species in low‐dimensional copper halides remain elusive. Here, a comprehensive study on the STE formation dynamics of one‐dimensional CsCu2I3 and zero‐dimensional Cs3Cu2I5 is presented. It is found from STE kinetic analysis that a slower STE formation demonstrated by the 1D structure is not hindered by a potential barrier, but instead related to the number of phonons released in the self‐trapping process. It is further revealed that in 1D CsCu2I3, the non‐radiative recombination of STEs mainly occurs via the intersection between the STE state and the ground state in the configuration coordinate diagram, placing an intrinsic limit on the PLQY at room temperature. These findings show that the STE formation is affected by both the self‐trapping depth and the phonon energy as opposed to a potential barrier in low‐dimensional copper halides. The better understanding of STE formation and recombination processes provide basis for improving design and performance for broadband light emitting devices.

Highly photoluminescent, lead‐free perovskites are of interest for displays and solid‐state light‐emitting devices. In this report, streak camera‐based time‐resolved emission and transient absorption spanning visible to deep‐ultraviolet (UV) wavelengths are utilized to study self‐trapped and free exciton dynamics in vacuum‐deposited cesium copper halide thin films of CsCu2I3 and Cs3Cu2I5. Self‐trapped exciton emission of CsCu2I3 exhibits more noticeable changes with time in the peak position and width than Cs3Cu2I5. UV‐to‐blue emission is detectable for both compositions, where free exciton emission is distinct for CsCu2I3. Transient absorption shows loss of ground‐state bleach signals at early time delays for both, and the bleach signal shifts toward higher energy as time delay increases, likely due to strains induced by the newly created self‐trapped excitons. Global analysis performed on the transient absorption results yields time constants in these materials that build an overall dynamic scheme. This work aids in building a complete picture regarding light emission in these promising materials.

Materials for radiation detection are critically important and urgently demanded in diverse fields, starting from fundamental scientific research to medical diagnostics, homeland security, and environmental monitoring. Low-dimensional halides (LDHs) exhibiting efficient self-trapped exciton (STE) emission with high photoluminescence quantum yield (PLQY) have recently shown a great potential as scintillators. However, an overlooked issue of exciton-exciton interaction in LDHs under ionizing radiation hinders the broadening of its radiation detection applications. Here, we demonstrate an exceptional enhancement of exciton-harvesting efficiency in zero-dimensional (0D) Cs3Cu2I5:Tl halide single crystals by forming strongly localized Tl-bound excitons. Because of the suppression of non-radiative exciton-exciton interaction, an excellent α/β pulse-shape-discrimination (PSD) figure-of-merit (FoM) factor of 2.64, a superior rejection ratio of 10−9, and a high scintillation yield of 26 000 photons MeV−1 under 5.49 MeV α-ray are achieved in Cs3Cu2I5:Tl single crystals, outperforming the commercial ZnS:Ag/PVT composites for charged particle detection applications. Furthermore, a radiation detector prototype based on Cs3Cu2I5:Tl single crystal demonstrates the capability of identifying radioactive 220Rn gas for environmental radiation monitoring applications. We believe that the exciton-harvesting strategy proposed here can greatly boost the applications of LDHs materials. We propose and demonstrate an exciton-harvesting strategy in low-dimensional halides exposed to ionizing radiation, which enhances both scintillation efficiency and charged particle discrimination capability.

Recently synthesized industrially significant perovskites Cs3Cu2X5 (X=Cl,Br,I) are subjected to a density functional theory (DFT) investigation utilizing the CASTEP code. This study explores various physical features, including structural, optical, thermodynamic, elastic, mechanical, and electronic properties. There is a strong correlation between the optimized structure parameters and the existing experimental data, which demonstrates the reliability of our DFT-based computations. The band structure and density of states (TDOS and PDOS) analysis revealed that all the studied perovskites are direct band gap semiconductors, and Cs3Cu2Br5 has the smallest band gap (2.092 eV). We also discussed the mechanical and cell stability using the Born stability criterion and formation energy, respectively. The mechanical and dynamic stability of each phase is confirmed by the analysis of the elastic constants. According to the computed values of Pugh's and Poisson's ratios as well as Cauchy's pressure, all of the studied compounds are ductile in nature. The study of density of states, total charge density, and Mulliken atomic populations reveal that all the compounds have complex bonding with both ionic and covalent properties. Finally, utilizing the elastic constant data, the Debye temperatures of Cs3Cu2Cl5, Cs3Cu2Br5, and Cs3Cu2I5 have been determined as 82.90 K, 100.00 K, and 80.70 K, respectively. The analysis of thermodynamics (relatively low values of both ΘD and Kmin) as well as optical properties indicate that all the investigated materials have the potential to serve as thermal barrier coating (TBC) materials.