High-efficiency upconversion luminescence in UCNPs/CsPbBr3 nanocomposites enhanced by silver nanoparticles.

Upconversion nanocomposites with multiple light-emitting centers have attracted great attention as functional materials, but their low efficiency limits their further applications. Herein, a novel, to the best of our knowledge, system for nanocomposites consisting of upconversion nanoparticles (UCNPs) and perovskite quantum dots (PeQDs) assembled with Ag nanoparticles (NPs) is proposed. Upconversion luminescence (UCL) operation from PeQDs is triggered by near-infrared (NIR) sensitization through Förster resonance energy transfer (FRET) and photon reabsorption (PR). Especially, the photoluminescence (PL) emission efficiency is found to be significantly enhanced due to the increased energy transfer efficiency and radiative decay rate in the UCNPs/CsPbBr3 nanocomposites. The results offer new opportunities to improve the UCL properties of perovskites and open new development in the fields of LED lighting, solar cells, biomedicine, and so on.

Insights into Photogenerated Carrier Dynamics and Overall Water Splitting of the CrS3/GeSe Heterostructure.

Based on the nonadiabatic molecular dynamics (NAMD) simulations and the first-principles calculations, we explore the overall water-splitting schemes and the photogenerated carrier dynamics for two configurations (CG and CyG) of the CrS3/GeSe van der Waals heterostructures. The photocatalytic direct Z-schemes and carrier migration pathways for hydrogen and oxygen evolution reactions (HER/OER) are constructed based on the electronic properties. The solar-to-hydrogen efficiency (η'STH values) of the schemes can reach 10.60% and 10.17% and further rise under tensile strain. The NAMD results demonstrate similar transfer times of the electron/hole for HER/OER and more rapid electron-hole recombination in CG enables it to be superior to CyG in photocatalytic performance. Moreover, the Gibbs free energy indicates that both the HERs and OERs turn to spontaneously proceed with CG and CyG at pH = 0-12.37 and pH = 2.55-11.01, respectively. These facts reveal that the CrS3/GeSe heterostructure is promising in photocatalytic overall water splitting.

Multiple strategies of improving photocatalytic water splitting efficiency in 2D arsenic sesquichalcogenides.

Improving the solar-to-hydrogen efficiency has always been a significant topic in the field of photocatalysis. Based on first-principles calculations, herein, we propose multiple strategies to improve the photocatalytic properties of 2D arsenic sesquichalcogenides for full water splitting. The new configurations As2STe2 and As2SeTe2 monolayers, derived from the As2Te3 monolayers by surface modification, are manifested to be typical infrared-light driven photocatalysts. Notably, under the built-in electric field, As2STe2 and As2SeTe2 monolayers can fulfil overall water splitting and the predicted solar-to-hydrogen efficiencies even reach up to 36.19% and 29.36%, respectively. The Gibbs free energy calculations indicate that the OER can be successfully driven under light irradiation. In addition, the overpotentials can provide most of the energy for HER when illuminated, especially for As2STe2 with the . In addition, both As2S3 and As2Se3 monolayers are capable of satisfying the conditions for photocatalytic water splitting. Furthermore, the band gaps of As2Se3 and As2S3 can dramatically be narrowed by increasing the number of layers and doping, respectively. These findings provide a theoretical basis for As2X3 monolayers to achieve efficient photocatalytic water splitting.

Synergistic luminescence effect and high-pressure optical properties of CsPbBr2Cl@EuMOFs nanocomposites.

Metal-organic frameworks (MOFs) are a class of highly porous materials that have garnered significant attention in the field of optoelectronics due to their exceptional properties. In this study, CsPbBr2Cl@EuMOFs nanocomposites were synthesized using a two-step method. The fluorescence evolution of the CsPbBr2Cl@EuMOFs was investigated under high pressure, revealing a synergistic luminescence effect between CsPbBr2Cl and Eu3+. The study found that the synergistic luminescence of CsPbBr2Cl@EuMOFs remains stable even under high pressure, and there is no energy transfer among different luminous centers. These findings provide a meaningful case for future research on nanocomposites with multiple luminescent centers. Additionally, CsPbBr2Cl@EuMOFs exhibit a sensitive color-changing mechanism under high pressure, making them a promising candidate for pressure calibration via the color change of the MOF materials.

Dual transmission channels at metal-MoS2/WSe2 hetero-bilayer interfaces.

van der Waals heterostructures (vdWHs) open the possibility of creating novel semiconductor materials at the atomic scale that demonstrate totally new physics and enable unique functionalities, and have therefore attracted great interest in the fields of advanced electronic and optoelectronic devices. However, the interactions between metals and vdWHs semiconductors require further investigation as they directly affect or limit the advancement of high-performance electronic devices. Here we study the contact behavior of MoS2/WSe2 vdWHs in contact with a series of bulk metals using ab initio electronic structure calculations and quantum transport simulations. Our study shows that dual transmission paths for electrons and holes exist at the metal-MoS2/WSe2 hetero-bilayer interfaces. In addition, the metal-induced bandgap state (MIGS) of the original monolayer disappears due to the creation of the heterolayer, which weakens the Fermi level pinning (FLP) effect. We also find that the creation of the heterolayer causes a change in the Schottky barrier height (SBH) of the non-ohmic contact systems, whilst this does not occur so easily in the ohmic contact systems. In addition, our results indicate that when Al, Ag and Au are in contact with a MoS2/WSe2 hetero-bilayer semiconductor, a low contact barrier exists throughout the whole transmission process causing the charge to tunnel to the MoS2 layer, irrespective of whether the MoS2 is in contact with the metals as the nearest layer or as the next-nearest layer. Our work not only offers new insights into electrical contact issues between metals and hetero-bilayer semiconductors, but also provides guidance for the design of high-performance vdWHs semiconductor devices.

Suppressed Phase Separation of Mixed-Halide Perovskite Quantum Dots Confined in Mesoporous Metal Organic Frameworks.

Mixed-halide perovskite quantum dots (PeQDs) are the most competitive candidates in designing solar cells and light-emitting devices (LEDs) due to their tunable bandgap and high-efficiency quantum yield. However, phase separation in mixed-halide perovskites under illumination can form rich iodine and bromine regions, which change its optical responses. Herein, we synthesize PeQDs combined with mesoporous zinc-based metal organic framework (MOF) crystals, which can greatly improve the stability of anti-anion exchange, including photo-, thermal, and long-term stabilities under illumination. This unique structure provides a solution for improving the performance of perovskite optoelectronic devices and stabilizing mixed-halide perovskite devices.

Electron-phonon coupling, bipolar effects, and thermoelectric performance of the CuSbS2 monolayer.

The thermoelectric performance of the CuSbS2 monolayer is determined using the relaxation times obtained from electron-phonon coupling calculations and the transport properties of phonons and electrons. Based on the fully relaxed structure, the lattice thermal conductivity and the electronic transport coefficients are evaluated by solving the Boltzmann transport equation for phonons and electrons under relaxation time approximation, respectively. The tendencies of the transport coefficients depending on the carrier concentrations and temperatures are studied to understand the thermoelectric performance. Based on the bipolar effect, the transport coefficients and intrinsic carrier concentrations, we determined the dimensionless figure of merit ZT in the 300-800 K range. The results demonstrate that the CuSbS2 monolayer should be an p-type semiconductor, and the maximum ZT of 1.36 is obtained, indicating that the monolayer is a good candidate for high-temperature thermoelectric devices. Substantial bipolar effects are observed, and the ones in the x-direction are stronger in comparison to those in the y-direction, which is responsible for the smaller ZT in the x-direction.

Efficient photocatalytic hydrogen evolution and CO2 reduction by HfSe2/GaAs3 and ZrSe2/GaAs3 heterostructures with direct Z-schemes.

The elaborate configuration of the heterostructure is crucial and challenging to achieve high solar-to-hydrogen efficiency or CO2 reduction efficiency . Here, we predict two heterostructures composed of HfSe2, ZrSe2, and GaAs3 monolayers. The maximum of 42.71%/35.12% with the heterostructures can be reached with the perfect match between the bandgap and band edges. The configurations of the heterostructures are discovered from 12 possible stacking types of the three monolayers. The formation energy, potentials of band edges, carrier mobilities, and optical absorption were used to identify the feasibility of the CO2 reduction reaction (CO2RR), the hydrogen evolution reaction (HER), and the oxygen evolution reaction (OER). The and based on overpotentials and bandgaps and the Gibbs free energies (ΔGs) are evaluated to quantificationally access the photocatalytic performance of the constructed heterostructures. The results demonstrate that high can be obtained for the solar photocatalytic Z-schemes with the HfSe2/GaAs3 and ZrSe2/GaAs3 heterostructures, and these values can be further enhanced through strain engineering. Moreover, small changes in ΔGs were observed for HER, OER, and CO2RR. Therefore, the two heterostructures have excellent performance in photocatalytic hydrogen evolution and CO2 reduction. The results of the electronic properties revealed that the delicate matching of the projected band edges of the monolayers in the heterostructures is responsible for the high photocatalytic performance.

Pressure-induced distinct excitonic properties of 2D perovskites with isomeric organic molecules for spacer cations.

Spacer organic cations in two-dimensional (2D) perovskites play vital roles in inducing structural distortion of the inorganic components and dominating unique excitonic properties. However, there is still little understanding of spacer organic cations with identical chemical formulas, and different configurations have an impact on the excitonic dynamics. Herein, we investigate and compare the evolution of the structural and photoluminescence (PL) properties of [CH3(CH2)4NH3]2PbI4 ((PA)2PbI4) and [(CH3)2CH(CH2)2NH3]2PbI4 ((PNA)2PbI4) with isomeric organic molecules for spacer cations by combining steady-state absorption, PL, Raman and time-resolved PL spectra under high pressures. Intriguingly, the band gap is continuously tuned under pressure and decreased to 1.6 eV at 12.5 GPa for (PA)2PbI4 2D perovskites. Simultaneously, multiple phase transitions occur and the carrier lifetimes are prolonged. In contrast, the PL intensity of (PNA)2PbI4 2D perovskites exhibits an almost 15-fold enhancement at 1.3 GPa and an ultrabroad spectral range of up to 300 nm in the visible region at 7.48 GPa. These results indicate that the isomeric organic cations (PA+ and PNA+) with different configurations significantly mediate distinct excitonic behaviors due to different resilience to high pressures and reveal a novel interaction mechanism between organic spacer cations and inorganic layers under compression. Our findings not only shed light on the vital roles of isomeric organic molecules as organic spacer cations in 2D perovskites under pressure, but also open a route to rationally design highly efficient 2D perovskites incorporating such spacer organic molecules in optoelectronic devices.

Synthesis, structure, and luminescence properties of Europium/Cerium/Terbium doped strontium-anorthite-type green phosphor for solid state lighting.

Novel phosphor exploration and luminescence property regulation are two important strategies in pursing high performance phosphors for white light emitting diodes, and have attracted great attention from the researchers. Herein, novel green phosphors Sr2Ga2SiO7:Eu2+ and Sr2Ga2SiO7:Ce3+,Tb3+ had been obtained by high-temperature solid-state reactions and their luminescence properties had been investigated in detail. Powder X-ray diffraction and Rietveld structure refinement results verified the phase purity and gave the crystal structure of the prepared samples. Due to the electric dipole transition between inter configurations of 4fN and 4fN-15d1, Sr2Ga2SiO7:Eu2+ and Sr2Ga2SiO7:Ce3+ exhibited intense broad excitation and emission bands, giving out green and blue emitting light under UV excitation, respectively. By codoping Tb3+ with Ce3+ in the host and utilizing the energy transfer, tunable blue to green emission had been obtained. The energy transfer mechanism had been determined to be electric dipole-quadrupole interaction through dynamic luminescence analysis using I-H model. The prepared phosphors exhibited good thermal stability with integral emission intensity at 150 °C remaining more than 80 % of the emission intensity at 25 °C. Moreover, by coating Sr2Ga2SiO7:Eu2+ and Sr2Ga2SiO7:Ce3+,Tb3+ on UV chips, green LED devices had been obtained. The investigation results indicated that the Eu2+ singly doped and Ce3+-Tb3+ codoped Sr2Ga2SiO7 might be potential UV excited green phosphors for solid state lighting.

Molecular Simulation Study on the Aging Mechanism of NEPE Propellant Matrix.

Polyethylene glycols (PEG) and toluene diisocyanate (TDI) are often used as the main components of binders and curing agents in solid propellants, and their aging is an important issue in the storage and use of propellants. To study the aging behavior and aging mechanism of nitrate ester plasticized polyether propellant (NEPE) matrix during storage, the transition states of aging reactions of binder and curing agent were optimized at the (U)B3LYP/6-311G(d,p) level of theory, and the rate coefficients over the temperature range of 298-1000 K were calculated by CVT theory. The results showed that there were five kinds of aging reactions for binder, which included decomposition, nitration, H abstraction, oxidation, and crosslinking reactions. Among them, theenergy barriers of oxidation and H abstraction reactions were relatively low (79.3-91.2 kJ·mol-1) and the main reaction types of binder aging. The main aging reaction of curing agent was decomposition. Compared with the aging reactions of binder, the energy barriers of curing agent are higher (196.6-282.7 kJ·mol-1) and the reaction is more difficult to occur. By comparing the energy barriers and rate constants of different reactions, it is found that the aging of NEPE propellant matrix can be divided into two stages. In the first stage, the propellant matrix mainly undergoes H abstraction and oxidation reaction, and as the reaction proceeds, the products crosslink to form -O-O-, -C-C-, and -C-O-C- bonds. At this time, the long chain molecules of the propellant matrix crosslink, and the molecular weight increases. This stage corresponds to the rising stage of mechanical properties in the aging process of the propellant. In the second stage, the propellant matrix mainly undergoes decomposition and nitration, resulting in degradation, the reduction of molecular weights, and the appearance of holes and microcracks in the matrix. This stage corresponds to the decline of mechanical properties in the aging process of the propellant. The above simulation results are in good agreement with the aging experimental phenomena, revealing the microscopic mechanism of the changes in the macroscopic properties of NEPE propellant during the aging process, and providing a theoretical basis for the related research on the aging properties and anti-aging technology of NEPE propellant.

Multi-color UCNPs/CsPb(Br1-xIx)3 for upconversion luminescence and dual-modal anticounterfeiting.

Advanced hybrid materials have attracted extensive attention in optoelectronics and photonics application due to their unique and excellent properties. Here, the multicolor upconversion luminescence properties of the hybrid materials composed of CsPbX3(X = Br/I) perovskite quantum dots and upconversion nanoparticles (UCNPs, core-shell NaYF4:25%Yb3+,0.5%Tm3+@NaYF4) is reported, achieving the upconversion luminescence with stable and bright of CsPbX3 perovskite quantum dots under 980 nm excitation. Compared with the nonlinear upconversion of multi-photon absorption in perovskite, UCNPs/CsPbX3 achieves lower power density excitation by using the UCNPs as the physical energy transfer level, meeting the demand for multi-color upconversion luminescence in optical applications. Also, the UCNPs/CsPbX3 combined with ultraviolet curable resin (UVCR) shows excellent water and air stability, which can be employed as multicolor fluorescent ink for screen printing security labels. Through the conversion strategy, the message of the security labels can be encrypted and decrypted by using UV light and a 980 nm continuous wave excitation laser as a switch, which greatly improves the difficulty of forgery. These findings provide a general method to stimulate photon upconversion and improve the stability of perovskite nanocrystals, which will be better applied in the field of anti-counterfeiting.

Molecular structure and spectroscopic properties of two radicals of C4H2N: a DFT study.

CONTEXT: The cyano propargyl radical (CH2C3N and HC3HCN) is important reaction intermediate in both combustion flames and extraterrestrial environments such as cold molecular clouds and circumstellar envelopes of carbon stars. The acquisition of spectroscopic constants and anharmonic effect facilitates a more in-depth study of this radical. However, the data available in the literature do not allow the precise predictions for it in the interstellar medium. In this work, complete spectroscopic parameters as well as anharmonic constants of two radicals of C4H2N have been evaluated by different DFT methods. The calculated results show that it is reasonable to study the molecular spectroscopic properties of C4H2N by wB97XD/6-311++G theoretical level. On this basis, the sextic centrifugal distortion constants, anharmonic constants, vibration-rotation interaction constants, and so on are predicted for the study of high-precision rovibrational spectrum. In addition, the relationship between the anharmonic effect and vibration mode of CH2C3N and HC3HCN and their infrared spectroscopic characteristics are discussed. METHODS: The calculation of the anharmonic force fields and spectroscopy properties was performed using B3LYP, B3PW91, CAM-B3LYP, and wB97XD methods combined with the 6-311++G and aug-ccpVTZ basis sets, respectively, by the Gaussian16 program suite. The IR spectra were performed with Multiwfn3.8.

LiXO2(X = Co, Rh, Ir) and solar light photocatalytic water splitting for hydrogen generation.

Alkali metal transition oxide LiCoO2 has been successfully commercialized as a lithium-ion battery material, and some attention is paid to its homologous derivatives LiRhO2 and LiIrO2. However, the photocatalytic properties have not been explored yet for these compounds. Using the first-principles calculations, we carry out investigations on the electronic properties, light absorption, and mobility to understand the feasibility of LiXO2(X = Co, Rh, Ir) for solar light photocatalytic hydrogen generation from water-splitting. The results show that the band edges of LiCoO2 and LiRhO2 meet the redox potential requirements of the water-splitting hydrogen evolution reaction. In addition, the enhanced absorptions of LiXO2(X = Co, Rh, Ir) in the visible light range imply that they could well respond to solar light, while the significant difference in the mobilities of electrons or holes can strengthen spatial charge separation of the photoexcited electron-hole pairs. The solar-energy-to-hydrogen conversion efficiencies of LiCoO2 and LiRhO2 can reach 11.2% and 15.5%, respectively. The results support LiCoO2 and LiRhO2 as promising candidates for visible-light photocatalytic hydrogen production from water-splitting.

Two-dimensional ZnO/BlueP van der Waals heterostructure used for visible-light driven water splitting: A first-principles study.

Solar driven water splitting for hydrogen generation has been considered as an important method for collecting clean energy. Herein, based on first-principles calculations, we propose that ZnO/BlueP van der Waals heterostructure can realize overall water splitting reaction for hydrogen generation. Strikingly, the band-gap of 1.83 eV is appropriate, and band alignments straddle the water redox potentials, ensuring the occurrence of hydrogenevolutionreaction and oxygen evolution reaction. Charge density distribution and carrier mobility exhibit significant charge separation and transfer. Visible-light response is improved compared with those of the isolated monolayers. Moreover, hydrogenevolutionreaction is actually realized on the ZnO layer, while oxygen evolution reaction is implemented on the BlueP layer. Through the investigation of the adsorption and dissociation reactions of H2O, we observe that two neighboring H*s prefer to combine to form H2 by overcoming a lowered energy barrier of 0.75 eV. Strain effect indicates that the lateral compressive strain of -4% to 0% and the vertical tensile strain of 0% to +6% can effectively tune band-gap and band alignments. The results indicate that ZnO/BlueP vdW heterostructure is probable highly efficient photoelectric material used for visible-light driven water splitting for hydrogen generation.

Tunable Dirac states in doped B2S3 monolayers.

Two-dimensional (2D) Dirac materials have been a research hotspot due to their intriguing properties, such as high carrier mobility and ballistic charge transport. Here, we demonstrate that the B2S3 monolayer with a hexagonal structure, which has been reported as a photocatalyst, can be tuned to new 2D Dirac materials by doping atoms. The Young's modulus can reach 65.23 N m-1, indicating that the monolayer can be used as a buffer materials. The electronic structures of the pristine B2S3 monolayer show that some Dirac points appear but do not occur exactly on the Fermi level (EF). Fortunately, we find that the Dirac cone can be tuned to the EF by doping C, N, or Sn atoms. The C-doped B2S3 monolayer can be a half-metallic Dirac material, which has significant potential application in spintronics. For N- and Sn-doped B2S3 monolayers, the typical kagome bands are formed near the EF, which arise from three molecular orbitals hybridized by B, S, and N (Sn) atoms. These outstanding properties render the doped B2S3 monolayers promising 2D Dirac materials for future nanoelectronic devices.

The molecular structure and spectroscopic properties of C3H2O and its isomers: An ab initio study.

The spectroscopic parameters and anharmonic force fields of three isomers (c-H2C3O, HCCCHO and CH2CCO) of C3H2O have been calculated by Density Functional Theory (B3LYP, CAM-B3LYP, wB97XD) and second-order Møller-Plesset perturbation theory (MP2) combining with 6-311++G (3df, 3pd) and aug-cc-pVTZ basis sets. The equilibrium geometries, energies, rotational constants, harmonic and fundamental frequencies, and centrifugal distortion constants of three isomers of C3H2O are calculated and compared with the existed results. The anharmonic constants, vibration-rotation interaction constants, Coriolis coupling constants and force constants of three isomers of C3H2O are firstly predicted. The ingredients of complex vibration modes, and infrared spectral characteristics of three isomers as well as the relationship between structure and spectroscopic properties are detailedly discussed.

2D XBiSe3(X = Ga, In, Tl) monolayers with high carrier mobility and enhanced visible-light absorption.

The geometrical configurations of the XBiSe3 (X = Ga, In, Tl) monolayers are identified by employing the first-principles density functional theory calculations, and the stabilities are confirmed by phonon dispersion, formation energy, and ab initio molecular dynamics simulation, respectively. The bandgap and band edges, the density of states, the optical absorption, mobility, and effect of strain engineering are evaluated to understand the photoelectronic properties of the monolayers. The results show that the XBiSe3 monolayers have the indirect bandgaps of 1.14-1.69 (1.20-1.84) eV by HSE06(GW), leading to the enhanced optical absorption from the visible to near-ultraviolet region. The large mobility of the electron and hole are also observed, which is helpful for the separation and transfer of the photogenerated carrier pair. The band edges and bandgaps, as well as the optical absorptions, can effectively be tuned by strain engineering. It should be noted that the band edges of the InBiSe3 monolayer could satisfy the condition of redox potential for the hydrogen evolution reaction under the compressive strain heavier than -3%, implicating this monolayer can also be used for photocatalytic water splitting to produce hydrogen. Therefore, these monolayers have potential applications in photocatalytic materials or photoelectronic devices such as energy harvesters and visible-light sensors.

Luminescence property improvement and controllable color regulation of a novel Bi3+ doped Ca2Ta2O7 green phosphor through charge compensation engineering and energy transfer.

In pursuit of warm WLEDs, exploration of novel phosphors and regulation of the existing phosphors are the two approaches usually used in the luminescent material field. In this work, we prepared green Ca2Ta2O7:Bi3+ phosphors firstly and investigated their properties in detail. The as-prepared Ca2Ta2O7:Bi3+ exhibits intense green emission in the 450-580 nm range under UV excitation, which matches well with the UV chip and can efficiently avoid the re-absorption problem. The improvement in the emission intensity and thermal stability of the phosphor was achieved using different charge compensation methods including codoping alkali metal ions (Li+, Na+, and K+), creating a cation vacancy, and host co-substitution (Ca2+ + Ta5+ → Bi3+ + Si4+, Ca2+ + Ta5+ → Bi3+ + Ge4+). Through systematic research, the emission intensity at room temperature was improved 2.1 times and the thermal stability was improved 2.9 times at 200 °C. By coating the prepared green sample with other commercial phosphors on the UV chip, warm WLEDs with Ra being 91.1 and CCT being 3990 K were obtained. Moreover, taking the Bi3+ → Eu3+ energy transfer strategy, the emitting color of the phosphor was tuned and yellow emitting phosphor was obtained. Our study indicates that Bi3+ doped Ca2Ta2O7 might be a potential UV excited green phosphor for WLEDs. The charge compensation methods and the Bi3+ → Eu3+ energy transfer approach are valuable ways to improve and adjust the luminescence properties, which can further derivate a series of novel phosphors for improving the quality of WLED devices.

STED microscopy reveals in-situ photoluminescence properties of single nanostructures in densely perovskite thin films.

All-inorganic perovskite nanomaterials have attracted much attention recently due to their prominent optical performance and potential application for optoelectronic devices. The carriers dynamics of all-inorganic perovskites has been the research focus because the understanding of carriers dynamics process is of critical importance for improving the fluorescence conversion efficiency. While photophysical properties of excited carrier are usually measured at the macroscopic scale, it is necessary to probe the in-situ dynamics process at the nanometer scale and gain deep insights into the photophysical mechanisms and their localized dependence on the thin-film nanostructures. Stimulated emission depletion (STED) nanoscopy with super-resolution beyond the diffraction limit can directly provide explicit information at a single particle level or nanometer scale. Through this unique technique, we firstly study the in-situ dynamics process of single CsPbBr3 nanocrystals(NCs) and nanostructures embedded inside high-dense samples. Our findings reveal the different physical mechanisms of PL blinking and antibunching for single CsPbBr3 NCs and nanostructures that correlate with thin-film nanostructural features (e.g. defects, grain boundaries and carrier mobility). The insights gained into such nanostructure-localized physical mechanisms are critically important for further improving the material quality and its corresponding device performance.