Extrinsic Defects Research Articles

Improvement of thermal damage resistance of SrAl2O4:Eu2+, Dy3+ persistent phosphor by a low temperature pre-annealing and its mechanism

SrAl2O4:Eu2+, Dy3+ as an excellent persistent phosphor has been widely applied in many fields. However, the high temperature induced thermal failure has always been a bottleneck problem restricting its long-term development. In this study, a simple pre-annealing method was utilized to improve the thermal damage resistance ability of SrAl2O4:Eu2+, Dy3+ persistent phosphors. After annealing at 900 °C, the afterglow duration time of the phosphor pre-annealed at 400 °C reached 233 min, which was twice longer than that of the phosphor without pre-annealing. An extrinsic vacancy defect migration theory at an elevated temperature was proposed to explain the interesting phenomenon. This study introduced a path to enhance the thermal stability of SrAl2O4:Eu2+, Dy3+ persistent phosphors and provided a thought to design persistent luminescence materials with desired thermal stability.

Spray pyrolysis grown Cu and Ni co-doped ZnO thin films: a study of their structural, optical, wettability, and photocatalytic performance

This study explores the impact of Cu and Ni doping on the structural, wettability, optical, and photocatalytic properties of ZnO thin films. The co-doped thin films, with varying Ni concentrations, were deposited using a spray pyrolysis method onto pre-heated soda lime glass substrates. X-ray diffraction analysis confirmed the hexagonal wurtzite structure with preferred orientation primarily along the (002) plane, while crystallinity decreased with higher Ni concentrations. Scanning electron microscopy reveals a compact, adherent structure in all films, with Ni incorporation altering the surface morphology. Fourier transform infrared spectroscopy identified characteristic absorption bands for metal-oxygen bonds. Optical analysis indicated that all thin films exhibited over 88% average transmittance in the visible region, accompanied by a red shift in the optical bandgap. Photoluminescence spectra exhibited a broad emission band in the visible region, indicating intrinsic and extrinsic defects induced by doping. Co-doping transforms the wettability character of ZnO thin films from hydrophilic to hydrophobic. Finally, the photodegradation efficiency of the thin films against methylene blue under sunlight significantly increases from 72% to 92% with an increase in Ni concentration.

Reversible photochromic effect and excellent mechanical properties of Nd3+-doped Zr6Nb2O17 purple ceramics

The development of colored ceramics is limited because it can only display a single color. Therefore, colored ceramics that can achieve reversible switching between two different colors can make up for this deficiency. In this study, we report a novel rare-earth doped colored ceramic, Zr6Nb2O17: xNd3+ (abbreviated as ZNO: xNd), which has been successfully obtained with good mechanical and photochromic properties of purple ceramics by component adjustment. The doping of rare earth Nd3+ ions changed the color of the ceramic matrix from light curry to light purple, and more importantly, enhanced its mechanical properties, with optimal Vickers hardness and fracture toughness values of 16.53 GPa and 5.2 MPa·m1/2, respectively. Alternating 365 nm irradiation and 350°C thermal stimulation, the ceramic samples exhibited good photochromic properties, with the highest photochromic contrast of 21.1 %, and good reversibility and cyclic stability. Finally, it is important to clarify that the photochromic mechanism is mainly caused by the formation of color centers resulting from electrons or holes being trapped by intrinsic or extrinsic defects. These results indicate that ZNO: xNd purple ceramics can be applied in the field of colored ceramics and provide a new path for the development of rare earth-colored ceramics.

Surface engineering and concentration-dependent emission activated flexible tunable fluorescence from lignin-based N-doped carbon dots

Achieving the flexible and tunable fluorescence of lignin-based N-doped carbon dots (LCDs) remains a win–win yet challenging strategy. In this study, combining the surface engineering and concentration regulation strategy enabled the flexible adjustment of LCDs fluorescence emission from blue to yellow regions (345 to 560 nm). The surface electron-donor –OH groups not only enhanced the photoluminescence quantum yield (PLQY) to 14.75 % but activated the spectral shift of reduced LCDs (RLCDs). These arose from the reinforced π-electron conjugation and generated new –OH-related extrinsic defects with elevating concentration. Conversely, the electron-withdrawing CO groups participated in the blue-to-green fluorescence modulation. Still, they drastically reduced the PLQY of oxidized LCDs (OLCDs) to 2.13 %, due to the larger particle size and more non-radiative transfer induced by CO groups. Based on these, CDs/PVA films and printed fluorescent patterns with multicolor fluorescence were realized for anti-counterfeiting, and the RLCDs@Al2O3 hybrid facilitated the precise fluorescence fingerprint tracking and recognition. This study provided a facile strategy for enriching and developing novel LCDs with flexible fluorescence for their advanced applications.

Contrasting Ultra-Low Frequency Raman and Infrared Modes in Emerging Metal Halides for Photovoltaics.

Lattice dynamics are critical to photovoltaic material performance, governing dynamic disorder, hot-carrier cooling, charge-carrier recombination, and transport. Soft metal-halide perovskites exhibit particularly intriguing dynamics, with Raman spectra exhibiting an unusually broad low-frequency response whose origin is still much debated. Here, we utilize ultra-low frequency Raman and infrared terahertz time-domain spectroscopies to provide a systematic examination of the vibrational response for a wide range of metal-halide semiconductors: FAPbI3, MAPbI x Br3-x , CsPbBr3, PbI2, Cs2AgBiBr6, Cu2AgBiI6, and AgI. We rule out extrinsic defects, octahedral tilting, cation lone pairs, and "liquid-like" Boson peaks as causes of the debated central Raman peak. Instead, we propose that the central Raman response results from an interplay of the significant broadening of Raman-active, low-energy phonon modes that are strongly amplified by a population component from Bose-Einstein statistics toward low frequency. These findings elucidate the complexities of light interactions with low-energy lattice vibrations in soft metal-halide semiconductors emerging for photovoltaic applications.

The role of doping technology in the formation of nonlinear optical properties of LiNbO3:Mg:B crystals

Nonlinear optical coefficients dij were calculated quantitatively for two series of LiNbO3 crystals double-doped with Mg and nonmetallic B obtained by the methods of the solid-phase (SP) synthesis and homogeneous introduction (HG) of impurities. The addition of boron and the presence of MgLi extrinsic defects increased the efficiency of second-harmonic conversion. Homogeneously doped crystals have been found to be the most suitable medium for second-harmonic generation (SHG). The high value of the total nonlinear optical coefficient d33 (−70.742(5) × 10−9 cm/statV) and the extremely low photorefractive response make the LiNbO3:Mg:B crystal (4.2 mol%) obtained by the HG method promising for use in nonlinear optics.

Extrusion pretreatment of green Arabica coffee beans for lipid enhance extraction

Brazil is the world's largest producer and exporter of green coffee. Coffee beans have intrinsic and extrinsic defects that affect their chemical composition and the consumer perception of the beverage. The aim of this work is to evaluate the impact of extrusion process in green Arabica healthy and defective coffee beans in order to increase oil yield. The chromatographic analyses of the non-processed beans showed that caffeine, diterpenes and serotonin amides did not vary between the samples (p<0.05), while moisture and ash content varied significantly. The extrusion process followed by Soxhlet was optimized using central composite rotation design (CCRD) 22. Extrusion at the point selected as optimal (68ºC and 60 rpm) proved to be efficient when applied in combination with Soxhlet extraction, causing an increase of 61–81 % of oil yield (15.29 ± 0.42 % from defective beans and 16.42 ± 0.63 % from healthy beans), while its use combined with pressing (6.99 ± 0.08 %) was not significant compared to Soxhlet extraction alone (9.05 ± 0.24 %). Caffeine, diterpenes, serotonin amides and fatty acids methyl esters (FAMES) were analyzed in the oils where most of the fatty acids showed similar percentage values (p ≤ 0.05). The total diterpene content was higher in the extruded beans, while serotonin amides varied according to healthy and defective beans and pre-treatment (for defective grains), with defective grains showing consistently higher content compared to healthy grains (p ≥ 0.05). Caffeine content was similar between the healthy extruded, defective and defective extruded grains, with the lowest content in the healthy grain. It can be concluded that extrusion is a pre-treatment with a high impact in coffee oil yield. Green coffee oil is commercially explored by cosmetics and pharmaceutical industries due to its emollient and moisturizer properties. Besides, this oil protects skin against UV radiation. These properties are related to bioactive compounds present in the lipid fraction of coffee bean as diterpene esters, fatty acids and serotonin amides, which together justify this study.

Manipulating disorder within cathodes of alkali-ion batteries.

The fact that ordered materials are rarely perfectly crystalline is widely acknowledged among materials scientists, but its impact is often overlooked or underestimated when studying how structure relates to properties. Various investigations demonstrate that intrinsic and extrinsic defects, and disorder generated by physicochemical reactions, are responsible for unexpectedly detrimental or beneficial functionalities. The task remains to modulate the disorder to produce desired properties in materials. As disorder is often correlated with local interactions, it is controllable. In this Review, we explore the structural disorder in cathode materials as a novel approach for improving their electrochemical performance. We revisit cathode materials for alkali-ion batteries and outline the origins and beneficial consequences of disorder. Focusing on layered, cubic rocksalt and other metal oxides, we discuss how disorder improves electrochemical properties of cathode materials and which interactions generate the disorder. We also present the potential pitfalls of disorder that must be considered. We conclude with perspectives for enhancing the electrochemical performance of cathode materials by using disorder.

The electronic structure, optical property and n-type conductivity for W-doped α-Ga2O3: hybrid functional study

Based on the hybrid functional method, the electronic structure, optical property and electron effective mass of α-Ga2O3, together with the properties for intrinsic and extrinsic defects incorporated into α-Ga2O3 are studied. Obtained results indicate the α-Ga2O3 possesses a wide band gap (5.31 eV), small electron effective mass (0.22 m0) and a high visible light transmittance. The nonstoichiometric α-Ga2O3 is not an excellent n-type semiconductor. To improve the n-type conductivity, the W-doped α-Ga2O3 is studied. We find that W Ga is a promising n-type defect due to its relatively small ionization energy ϵ(0/+) (0.30 eV). When the equilibrium fabrication method is selected, the WO2 is a promising dopant source. Using the equilibrium fabrication method, the defect complex (V O+ W Ga) would be formed, and the ionization energy ϵ(0/+) for defect complex (V O + W Ga) would decrease to 0.08 eV, which implies that a great number of free electrons could be induced in the samples. We expect that this work can promote the understanding of the n-type conductivity for α-Ga2O3 and provide significant insights for the development of a transparent n-type semiconductor.

The effects of graphene intrinsic defects on the formation of extrinsic defects by plasma treatment

Two-dimensional materials, like graphene, are expected to make highly efficient permeation membranes for separation and sensing applications; however, defects of a specific size and location must be added to the film to make them selectively permeable. Though techniques like TEM drilling give precise information on size and location, this method is not scalable for eventual commercial use. Plasma treatments are a scalable alternative, but there is less information on where the defect formation begins and how intrinsic defects affect pore formation. This work seeks to understand these effects by using Raman spectroscopy at the same location before and after plasma treatments to map how the intrinsic defects affect the formation of extrinsic defects to create nanopores. Defect density increases with increasing RF power, independent of the gas used during the plasma treatment, suggesting that the mechanism is due to ion bombardment. Coalesced and arrested graphene syntheses are used to study the relative trends of defect formation and map existing graphene grain boundary locations. The results show that regions starting with high densities of intrinsic defects, potentially due to strain, were found to degrade into nanocrystalline graphene first on the amorphization trajectory, even before grain boundaries.

Li-Site Defects Induce Formation of Li-Rich Impurity Phases: Implications for Charge Distribution and Performance of LiNi0.5- xMxMn1.5O4 Cathodes (M = Fe and Mg; x = 0.05-0.2).

An understanding of the structural properties that allow for optimal cathode performance, and their origin, is necessary for devising advanced cathode design strategies and accelerating the commercialization of next-generation cathodes. High-voltage, Fe- and Mg-substituted LiNi0.5Mn1.5O4 cathodes offer a low-cost, cobalt-free, yet energy-dense alternative to commercial cathodes. In this work, the effect of substitution on several important structure properties is explored, including Ni/Mn ordering, charge distribution, and extrinsic defects. In the cation-disordered samples studied, a correlation is observed between increased Fe/Mg substitution, Li-site defects, and Li-rich impurity phase formation-the concentrations of which are greater for Mg-substituted samples. This is attributed to the lower formation energy of MgLi defects when compared to FeLi defects. Li-site defect-induced impurity phases consequently alter the charge distribution of the system, resulting in increased [Mn3+] with Fe/Mg substitution. In addition to impurity phases, other charge compensators are also investigated to explain the origin of Mn3+ (extrinsic defects, [Ni3+], oxygen vacancies and intrinsic off-stoichiometry), although their effects are found to be negligible.

The atomic configuration and metallic state of extrinsic defects in Nb-doped BiFeO3 thin films

Defects in ferroelectric materials can cause microscopic strain and electron doping, which opens up new possibilities for unique physical properties in nanoelectronics. However, comprehending the relationship between these deep-buried defect configurations and the resulting physical properties is a long-term challenge. Here, utilizing the integrated differential phase imaging technique equipped in scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy, we show the full element-resolved atomic configuration of characteristic extrinsic defects in Nb-doped epitaxial BiFeO3 thin films. Atomic-resolution characterization reveals that the Nb doping substitutes Fe at the center of an oxygen octahedron and creates Fe vacancies near the defect core, leading to the formation of one perovskite cell-wide BiNbO3 chain that is expanded by 19 % in perovskite cell volume and rotated by 45° relative to the matrix lattice. Further quantitative analysis of the defect demonstrates that the ferroelectric polarization distribution around the dopant-induced defects displays a “head-to-head” configuration, indicating the accumulation of negative charges. Supported by electron energy loss spectroscopy and density functional theory calculations, the linear defect leads to one-dimensional metallic channels embedded within the ferroelectric BiFeO3 matrix. These atomic-scale findings establish the structure-functionality relationship of extrinsic defect in Nb-doped BiFeO3 thin films, providing new insight into their fundamental understanding and potential use in low-dimensional nanoelectronics devices.

Nickel Oxide Hole Injection Layers for Balanced Charge Injection in Quantum Dot Light-Emitting Diodes.

Quantum dot (QD) light-emitting diodes (QLEDs) are promising for next-generation displays, but suffer from carrier imbalance arising from lower hole injection compared to electron injection. A defect engineering strategy is reported to tackle transport limitations in nickel oxide-based inorganic hole-injection layers (HILs) and find that hole injection is able to enhance in high-performance InP QLEDs using the newly designed material. Through optoelectronic simulations, how the electronic properties of NiOx affect hole injection efficiency into an InP QD layer, finding that efficient hole injection depends on lowering the hole injection barrier and enhancing the acceptor density of NiOx is explored. Li doping and oxygen enriching are identified as effective strategies to control intrinsic and extrinsic defects in NiOx, thereby increasing acceptor density, as evidenced by density functional theory calculations and experimental validation. With fine-tuned inorganic HIL, InP QLEDs exhibit a luminance of 45200cdm-2 and an external quantum efficiency of 19.9%, surpassing previous inorganic HIL-based QLEDs. This study provides a path to designing inorganic materials for more efficient and sustainable lighting and display technologies.

Nickel-hexagonal phase induced in Ni3Si-monoclinic intermetallic phase by ion beam irradiation

A hypereutectic Ni alloy with 22 at. % Si was irradiated with a high-energy nickel ion beam and high ion fluence at 650°C to induce the formation of intrinsic and extrinsic point defects. Under these irradiation conditions, high concentrations of point defects were formed in the irradiated region. The recovery process initiated due to the damage induced by irradiation led to the formation of a nanoparticle population in the irradiated region. The irradiated region was characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The experimental evidence obtained permitted the establishment of an event sequence that culminated in nanoparticle population formation. The event sequence had the following stages: (a) Ni atom population implantation within a specific zone of the irradiated region; (b) nucleation and growth of a Nickel-hexagonal phase due to ordering of the implanted nickel atoms; and (c) Ni-hexagonal phase nanoparticle growth within a specific region of the irradiated region. The HRTEM analysis yielded crucial insights into the mechanisms underlying nanoparticle formation. The two most important aspects are as follows: firstly, the nucleation of Nickel-hexagonal phase into an amorphous region, and secondly, the non-equilibrium nature of the Nickel-hexagonal phase of the Nickel metallic system. These experimental findings are important for implantation technology; implanting atomic species into certain materials to create composite materials can lead to the formation of non-equilibrium phases and amorphous regions. Both of these outcomes have the potential to adversely affect the properties of the composite material.

Defect engineering and alloying strategies for tailoring thermoelectric behavior in GeTe and its alloys

GeTe exhibits excellent p-type medium-temperature thermoelectric properties with low toxicity and good mechanical characteristics, making it highly promising for development in the thermoelectric field. However, GeTe is prone to producing Ge vacancies, leading to high p-type carrier concentration, which results in elevated electronic thermal conductivity and a low Seebeck coefficient. This study systematically analyzes intrinsic and extrinsic defects in GeTe and its alloys, focusing on reducing p-type carrier concentration through first-principles calculations. The results reveal that substituting Ge-sites with Bi (BiGe) yields lower donor defect formation energy, effectively reducing p-type carrier concentration of GeTe and its alloys compared to other elemental doping. Additionally, alloying with certain elements, such as Pb, proves favorable for decreased p-type carrier concentration due to lowered energy levels of valence band maximum (VBM). Inspired by this, screening divalent elements for alloying on Ge-sites reveals that Sr, Ba, Eu, and Yb substantially reduce the VBM of GeTe. Further calculations for Ba and Yb-alloyed GeTe confirm changes in formation energies for donor (favorable) and acceptor (unfavorable) defects. Our work provides a systematic investigation of intrinsic and various extrinsic doping defects in GeTe and its alloys, shedding light on possible strategies of optimizing carrier concentration in these compounds.

Investigating the effects of varying sulfur concentration on ZnSxSe1-x (0 ≤ x ≤ 1.0) thin films prepared by photo-assisted chemical bath method

Zinc sulfur-selenide (ZnSxSe1-x) (0 ≤ x ≤ 1.0) thin films were grown on glass substrates using photo-assisted chemical bath deposition technique and the deposited samples were annealed in an open-air furnace at 250 ℃ for 3 h. X-ray diffraction analysis revealed a phase transition from hexagonal ZnSe to cubic ZnS as x changes from 0 to 1.0. Raman scattering showed two longitudinal optical modes due to ZnSe structure. The effects of S and Se ions variation is observed by the change in surface morphology from nanoflakes to spherical particles as x increased. The presence of the expected elementary composition was confirmed by the energy dispersive x-ray spectroscopy. The bandgap of the films was found to increase from 2.68 to 3.50 eV with a corresponding decrease in crystallite size (11.9 – 7.1 nm) as x varied from 0 to 1.0. Photoluminescence excitation and emission showed defect emission peaks ascribed to intrinsic and extrinsic deep level defects such as Zn2+ or S2- ions vacancies and interstitials. The emission colours were tuned from red to yellowish-green with increased x values as confirmed from Commission Internationale de L’Eclairage analysis. The tunability of the ZnSxSe1-x structural, optical and morphological properties makes it a good candidate for optoelectronic applications.

Intrinsic heterogeneity of grain boundary phase transitions in the Cu–Bi system: insights from grain boundary diffusion measurements

Abstract Diffusion of Bi and Ag in a series of polycrystalline Cu–Bi alloys is investigated using a radiotracer technique and applying the 207Bi and 110m Ag isotopes, respectively. Together with the previous measurements (Divinski S., Lohmann M., Herzig C., Straumal B., Baretzky B., Gust W. Grain-boundary Melting Phase Transition in the Cu−Bi System. Phys. Rev. B 2005, 71, 104104), a temperature–concentration interval of strong, by orders of magnitude, enhancements of Bi grain boundary diffusion rates is distinguished and the results are interpreted in terms of a grain boundary pre-wetting/wetting phase transition. Grain boundary diffusivity of Ag exhibits as well a step-wise increase with rising Bi content, mirroring the behaviour observed for the Bi tracer. However, contrary to the Bi tracer atoms for which grain boundary enhancement is observed at about 60 ppm of Bi in Cu–Bi alloys, this transition is revealed by the Ag tracer atoms at a significantly higher concentration, specifically between 90 and 100 ppm of Bi at 1080 K. The Ag diffusion rates in alloys with a moderate Bi content turn out to be not affected by the Bi-induced grain boundary phase transition and the measured grain boundary diffusion coefficients of Ag are nearly the same as those determined for pure polycrystalline Cu. This spectacular result suggests a strong heterogeneity of Bi segregation and Bi-induced phase transition for general high-angle grain boundaries in a given alloy. The behaviour is discussed in terms of the extrinsic grain boundary defects and their impact on mechano-chemical coupling which is accompanying the grain boundary phase transitions.

Extrinsic defects-rich biochar for efficient peroxydisulfate activation: Electronic structure modulation and disparate nonradical mechanisms

Doping nitrogen atoms into carbon materials will produce abundant extrinsic defects, which can significantly improve the catalytic activity toward water remediation. However, there is still a lack of systematic research on which extrinsic defect is the real active site and how extrinsic defects enhance the catalytic activity of carbon materials. In this work, the sludge derived biochar with different configuration of extrinsic defects (pyrrolic-N, pyridinic-N, and graphitic-N.) were successfully synthesized by controlling nitrogen doping amount. The adsorption experiments showed that the biochar with rich graphitic-N significantly enhanced the adsorption ability of peroxydisulfate (PDS), which further led to the excellent catalytic activity toward norfloxacin (NOR) degradation, with 91 % removal efficiency within 90 min. The pseudo-first-order degradation rate constant (Kobs) was strongly positively correlated with the content of graphitic-N. Electron paramagnetic resonance (EPR) analysis and quenching experiments revealed that metastable reactive species (PDS*) were the dominated reactive species in NBC/PDS system. Besides, density functional theory (DFT) calculations demonstrated that the existence of graphitic-N most effectively improved the charge transfer among biochar, PDS and NOR compared to pyrrolic-N and pyridinic-N. Electrochemical characterization and Raman results further identified that graphitic-N heightened the direct electron transfer rate due to the formation of PDS*. The Fukui function predicted the reactive sites of NOR. All of these led to the high NOR removal efficiency. This study provided new insights for the design of non-metallic biochar catalysts with rich extrinsic defects for effectively activating PDS to degrade fluoroquinolone antibiotics.

A first-principles study of the electronic structure and point defects in higher manganese silicide Mn4Si7.

Point defects play a crucial role in determining the physical properties of solid-state semiconductor materials. However, theoretical investigations dedicated to point defects in higher manganese silicides (HMSs), promising thermoelectric materials composed of earth-abundant and eco-friendly elements, are surprisingly absent in the literature. Here, using first-principles calculations we systematically investigate the intrinsic and extrinsic point defects in a HMS, Mn4Si7. Our results indicate that the formation energies of intrinsic defects in Mn4Si7 are sufficiently high to preclude their significant concentration under thermal equilibrium growth conditions, and the experimentally observed p-type conductivity of the pure HMS could be a result of self-doping. Additionally, we calculated the defect formation energies of 14 candidate dopants by fully considering the secondary phases, which are in good agreement with experimental findings. Our results provide valuable guidance for optimizing the doping strategy of HMSs for device applications.

Defects of perovskite semiconductor CsPbBr3 investigated via photoluminescence and thermally stimulated current spectroscopies

Halide perovskites are essential materials for hard radiation detectors at ambient temperature. To improve detector performance, charge transport must be investigated and optimized. Using photoluminescence (PL) and thermally stimulated current (TSC) spectroscopies, we investigate photogenerated charge carriers in Bridgman-grown CsPbBr3 single crystals to understand the nature of charge transport. PL spectroscopy of these halide perovskites revealed the presence of strong emission bands at the band edge, which were attributed to free or bound excitons. It is shown that a wide broadening of the excitonic linewidth in these halide perovskites arises from strong exciton–phonon coupling, which is substantially dominated by longitudinal optical phonons via Fröhlich interaction. An additional contribution due to the presence of ionized impurities was also observed. Crystals with a detectable sensitivity to high-energy gamma radiation are characterized by a higher intensity and a narrower linewidth of the principal PL peak at 2.326 eV. Defect states beyond 2.214 eV have a negative impact on detector sensitivity to high-energy gamma radiation. TSC spectroscopy reveals an array of trap levels spanning 0.15–0.70 eV, attributed to intrinsic point defects and multiple extrinsic defects involving dopants or impurities. Defects identified included Cs and Br vacancies, as well as Pb interstitials with concentrations in the 1011–1016 cm−3 range. Understanding how the synthesis process impacts the types and concentrations of the defects present is currently under investigation. Elimination or suppression of the defect/trap states should result in halide perovskite materials with longer carrier diffusion lengths and improved detector characteristics.