Common Dopants Research Articles

Carbon and Silicon Impurity Defects in GaN: Simulating Single-Photon Emitters by First Principles.

Defect single-photon emitters (SPE) in gallium nitride (GaN) have garnered great attentions in recent years due to the advantages they offer, including the ability to operate at room temperature, narrow emission linewidths, and high brightness. Nevertheless, the precise nature of the single-photon emission mechanism remains uncertain due to the multitude of potential defects that can form in GaN. In this work, our systematical investigation with the ab initio calculation indicates that carbon and silicon, as common dopants in gallium nitride, can interact with intrinsic defects in GaN and form new high-speed defect single-photon sources. Our findings identify a ternary defect NGaVNCN that possesses a short lifetime of less than 1 ns and a small zero-photon line (ZPL) of 864 nm. In other words, this defect can serve as a high-speed single photon source in the short wavelength window for fiber communication. In sharp contrast, the Si-supported defect NGaVNSiN has a higher unoccupied defect energy level which enters the conduction band and is therefore unsuitable for single photon emission. A systematic investigation has been conducted into the potential defects, thermal stability, and single-photon emission properties. The relaxation calculation and self-consistent calculations employed the Perdew-Burke-Ernzerhof exchange-correlation functional and Heyd-Scuseria-Ernzerhof exchange-correlation functional, respectively. These findings indicate the potential for high-performance single-photon sources through carbon or silicon doping of GaN.

Achieving n-type doped monoclinic (InxAl1-x)2O3 alloys

The monoclinic (In0.25Al0.75)2O3 alloy has been suggested as an ideal material to create monoclinic Ga2O3 heterostructures, as it provides a close lattice match to β-Ga2O3 along with a 1 eV conduction-band offset. Achieving intentional n-type doping in Ga2O3 heterostructures is important for device applications, but this may be difficult due to the high Al content of this alloy. Here, we use density functional theory with a hybrid functional to investigate common donor dopants, in particular, Si, Sn, C, and Ge substituting on cation sites, and H interstitials, in In2O3 and InAlO3. We identify Si as the optimal donor, as it is a shallow donor for In concentrations above 14%. Its formation energy is also low, indicating that these donors will incorporate during growth. For higher In concentrations, Sn (above 33% In) and Ge (above 35% In) are also promising donors, with Sn having comparable formation energies to Si.

Investigating the Molecular Orientation and Thermal Stability of Spiro-OMeTAD and Its Dopants By Near Edge X-Ray Absorption Fine Structure

This work describes the utilization of near edge X-ray absorption fine structure (NEXAFS) to investigate the hole transporting material (HTM) 2,2ʹ,7,7ʹ-tetrakis(N,N-di-p-methoxyphenylamine)- 9,9ʹ-spirobifluorene (Spiro-OMeTAD) and its most common dopants, lithium bis-(trifluoromethylsulfonyl) imide (LiTFSI), 4-tert-butylpiridine (tBP) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). Utilizing angle resolved NEXAFS, the orientation of the molecules on the surface can be observed. The data suggests it is difficult to determine any orientational preference for Spiro-OMeTAD deposited on a surface due to the 3D propeller-like geometry of this molecule. Both doped and undoped samples show thermal stability beyond the glass transition temperature of the molecules. Significant changes to the Spiro-OMeTAD spectra were observed with the addition of the dopants, in particular the C K-edge. Differences are also observed in the valence band spectra when dopants are added. It is also demonstrated how the doping combination of LiFTSI with tBP and, F4-TCNQ act as p-type dopants by altering the position of the HOMO levels. The F4-TCNQ induces a larger change in the HOMO levels when compared to the LiTFSI and tBP. These results are important to increase our understanding of Spiro-OMeTAD and the effect dopants have on this material for next generation solar cells.

A Highly Conductive n-Type Polythiophene Derivative: Effect of Molecular Weight on n-Doping Behavior and Thermoelectric Performance.

Here, we examine the impact of the molecular weight of an n-type conjugated polymer (n-PT2) on molecular doping and thermoelectric parameters. Two common dopants TDAE and N-DMBI with different doping mechanisms are used for molecular doping of n-PT2. It turns out that n-PT2 with a higher molecular weight is more miscible with the dopant, leading to more charge carriers. Moreover, the crystal structures and morphology of n-PT2 with a higher molecular weight are more tolerant against the intrusion of dopant molecules and charging. Finally, these factors work in synergy to endow the doped n-PT2 with the best conductivity and power factor (144 S cm-1/75.0 μW m-1 K-2 and 75.4 S cm-1/98.5 μW m-1 K-2 after doping by TDAE and N-DMBI, respectively). This study indicates that regulating the molecular weight allows for synergistic regulation of conductivity and Seebeck coefficient and is a feasible means to improve the performance for a given n-type organic thermoelectric material.

Investigating the Molecular Orientation and Thermal Stability of Spiro‐OMeTAD and its Dopants by Near Edge X‐Ray Absorption Fine Structure

AbstractThis study describes the utilization of near edge X‐ray absorption fine structure (NEXAFS) to investigate the hole transporting material (HTM) 2,2ʹ,7,7ʹ‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐ 9,9ʹ‐spirobifluorene (Spiro‐OMeTAD) and its most common dopants, lithium bis‐(trifluoromethylsulfonyl) imide (LiTFSI), 4‐tert‐butylpiridine (tBP), and 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4‐TCNQ). By changing the angle of the sample with respect to the beam, the orientation of the molecules on the surface can be observed. The data suggest that it is difficult to determine any orientational preference for Spiro‐OMeTAD deposited on a surface due to the 3D propeller‐like geometry of this molecule. Both doped and undoped samples show thermal stability beyond the glass transition temperature of the molecules. Significant changes to the Spiro‐OMeTAD spectra are observed with the addition of the dopants, in particular the C K‐edge. Differences are also observed in the valence band spectra when dopants are added. It is also demonstrated how the doping combination of LiFTSI with tBP and, F4‐TCNQ act as p‐type dopants by altering the position of the HOMO levels. The F4‐TCNQ induces a larger change in the HOMO levels when compared to the LiTFSI and tBP. These results are important to increase the understanding of Spiro‐OMeTAD and the effect dopants have on this material for next generation solar cells.

First-principles screening of surface-charge-transfer molecular dopants for n-type diamond

Surface charge transfer doping (SCTD) is an alternative approach to achieving n-type doped diamonds since the n-type bulk doping of diamonds remains a challenge, but so far efficient diamond n-type SCTD has not been achieved. Here we provide a comprehensive study of the n-type SCTD of the diamond by using first-principles calculations based on the density functional theory. Taking the principle that ionization potentials of the dopants must be higher than those of the diamond, we screened a series of molecules that may be suitable for diamond n-type SCTD doping. Methyl viologen and benzyl viologen provide the largest amount of transfer electron among the common n-type SCTD dopants for the oxygen and fluorine terminated (100) surface diamond, with the electron areal densities of and respectively. It is indicated that the transferred electron amount is positively correlated with the difference between the ionization potentials of the dopants and the electron affinity of the diamond, while the density of dopants also has a positive impact with a decreasing trend. The present work provides a useful understanding of the physical mechanism for the n-type SCTD of diamonds, and benefits the development of n-type SCTD diamond materials.

Low-temperature vacuum deposition of green phosphorescent OLED devices using close-space sublimation of spirobifluorene hosts

Commercial organic light-emitting diode (OLED) displays are mainly produced by line-of-sight vacuum thermal evaporation (VTE) methods that operate at high temperatures with low material utilization, exerting thermal stress on shadow masks and driving up costs. Further advancement of OLED displays towards higher resolutions at reduced cost demands more efficient deposition sources and OLED materials that can be reliably evaporated at low temperatures. In this study, we utilized close-space sublimation (CSS), an area deposition technique with a high material utilization rate, to lower the evaporation temperature of materials and deposition time drastically. By employing a spirobifluorene-based host that has a matching CSS profile with common iridium-based dopants, we have successfully reduced the evaporation temperature of the emitting layer (EML) to as low as 120 °C in CSS, less than half of the temperature required in VTE, and shortened the deposition time from minutes to seconds. The CSS-deposited green phosphorescent OLEDs exhibited comparable efficiencies with their VTE-deposited counterparts and demonstrated promising lifetimes.

Nitroxide-based triradical dopants for efficient low-temperature dynamic nuclear polarization in aqueous solutions over a broad pH range

Dynamic nuclear polarization (DNP) can provide substantial sensitivity enhancements in solid state nuclear magnetic resonance (ssNMR) measurements on frozen solutions, thereby enabling experiments that would otherwise be impractical. Previous work has shown that nitroxide-based triradical compounds are particularly effective as dopants in DNP-enhanced measurements at moderate magic-angle spinning frequencies and moderate magnetic field strengths, generally leading to a more rapid build-up of nuclear spin polarizations under microwave irradiation than the more common biradical dopants at the same electron spin concentrations. Here we report the synthesis and DNP performance at 25 K and 9.41 T for two new triradical compounds, sulfoacetyl-DOTOPA and PEG12-DOTOPA. Under our experimental conditions, these compounds exhibit ssNMR signal enhancements and DNP build-up times that are nearly identical to those of previously described triradical dopants. Moreover, these compounds have high solubility in aqueous buffers and water/glycerol mixtures at both acidic and basic pH values, making them useful in a wide variety of experiments on biomolecular systems.

Revealing the mechanisms of mercury adsorption on metal-doped kaolinite(001) surfaces by first principles

Natural kaolinite exhibit high affinity for heavy metals while the interaction mechanisms in the presence of heteroatoms remain largely elusive, which are tackled by first principles. In this paper, three common dopants (Mg, Ca, Fe) were employed to construct metal-doped kaolinite(001) (K(001)) surfaces. We found that Mg-doped K(001) was the most stable surface in terms of thermal stability and structural analysis, consistent with the pervasive isomorphic substitution in kaolinite minerals. The interaction of mercury with Mg-doped K(001) surface was investigated in the form of predominant top-site and bridge-site models. The effects of chloride on the interaction were also studied. The results demonstrated that the strongest adsorption occured in the present of dopants and the absence of chloride. The electronic properties revealed a significant charge transfer (up to 1.28 electrons) and chemisorption character at the interfaces when dopants were introduced, which could be ascribed to the overlapping of Hg-5d and Os-2p (surface O) orbitals in the range of −7.5 eV to +0.5 eV. Additionally, the chloride had a profoundly adverse influence on mercury adsorption due to the upward shift of Hg-6s and Hg-6p orbitals. The studies are beneficial to understand the interaction mechanisms of natural minerals toward environmental pollutants in actual applications.

Monitoring of Dose Dependent Damage in MeV Energy Hydrogen Implanted Silicon by Photo-Modulated Reflectance Measurements

High-energy low-mass proton implantation achieved considerable interest in semiconductor technology, due to much deeper penetration of hydrogen ions into silicon as compared to common dopants, boron, phosphorous, and arsenic. Accordingly, monitoring the accumulation kinetics and stability of proton-implantation induced defects and their influence on the optical and electrical properties of Si achieved increased attention both in technological process control and scientific research. We show that photo-modulated-reflectance (PMR) is effective technique to measure very low defect concentrations in the ppb-ppm range in high energy proton implanted silicon. After ion irradiation, the as-implanted dilute damage structure may lead to long term changes of the defect distribution and the formation of defect compounds due to mobility of point defects at room temperature. Moreover, low-mass hydrogen atoms may move significantly faster at room temperature compared to heavier dopants. We show that PMR is capable to detect differences in implanted proton dose with high sensitivity in a wide dose range, and, on a longer time scale, allows to follow changes in free carrier generation and recombination processes through the measurement of the long term decay of the PMR signal which is related to the sample response based on electro-optic and thermo-optic effects. Our experiments may pave the way toward high precision process control of device structure fabrication which utilizes the high-energy hydrogen implantation step. Also, our aim is to gain insight into the main processes underlying the dose dependent change and long-term decay of the PMR signal in high energy proton implanted Si.

A review on the effects of various elemental doping and nanostructuring of [formula omitted]-[formula omitted]/[formula omitted] composites on the thermoelectric performance enhancement

Thermoelectric device is a transformative technology for renewable energy generation. It is designed in a small compact feature with a quiet mechanism and has no gas emission, enabling it to conserve energy and preserve the global environment. Iron disilicide (β-FeSi2/Si) composite materials prepared by eutectoid reaction is found promising for thermoelectric applications. The strategies to enhance the thermoelectric properties of these composites are mainly by conducting band structure engineering such as elemental doping and nanostructure engineering. This article reviews the effects of elemental doping and nanostructuring of β-FeSi2/Si composite materials. Mn and Co were found to be the most common dopants due to their contribution to carrier mobility and carrier concentration. Other dopant elements such as Al, introduced point defects on the composite structure that is effective in lowering thermal conductivity. P was also found to be effective on both electronic and lattice contribution of thermal conductivity. Furthermore, in thin films structure, flatter surface is highly recommended rather than the crystallinity of films to enhance carrier mobility and suppress thermal conductivity. Thus, the way to optimize β-FeSi2/Si composite materials were discovered by the significant number of studies on refinement of composite structure into nanoscale. From these studies, electrical conductivity value was significantly enhanced while reducing its thermal conductivity and Seebeck coefficient value. The deterioration of Seebeck coefficient is yet to be improved hence was estimated possible by introducing doping mechanisms. Therefore, this review concludes some potential strategies for improving Seebeck coefficient while simultaneously increasing electrical conductivity and decreasing thermal conductivity towards enhancing its thermoelectric performance.

Diffusion of dopants and impurities in β-Ga2O3

The understanding and availability of quantitative measurements of the diffusion of dopants and impurities in Ga2O3 are currently at an early stage. In this work, we summarize what is known about the diffusivity of the common donor dopants, Sn, Ge, and Si, as well as some of the deep acceptors, N, Fe, and Mg, and donors, Ir. Two commonly encountered interstitial impurities are H and F, the former through growth and processing ambients and the latter through its use in plasmas used for stripping dielectrics from Ga2O3. Both are found to have high diffusion coefficients and an effect on electrical conductivity, and H shows anisotropy in its diffusion behavior. Si, Ge, and Sn implanted into bulk β-Ga2O3 at total doses from 2 × 1013 to 2 × 1015 cm−2 and annealed at 1100 °C for 10–120 s in either O2 or N2 ambients showed a significant effect of the annealing ambient on the donor's diffusivity. In the case of O2 annealing, there was extensive redistribution of the Si, Sn, and Ge across the entire dose range, while, in sharp contrast, the use of N2 annealing suppressed this diffusion. The N2 ambient also suppressed loss of dopants to the surface, with >90% of the initial dose retained after annealing at 1100 °C for 120 s, compared to 66%–77% with O2 anneals under the same conditions.

Multimodal gadolinium oxysulfide nanoparticles for bioimaging: A comprehensive biodistribution, elimination and toxicological study

For some years now, gadolinium oxysulfide nanoparticles (NPs) appear as strong candidates for very efficient multimodal in vivo imaging by: 1) Magnetic Resonance (MRI), 2) X-ray Computed Tomography (CT) and 3) photoluminescence imaging. In this paper, we present a selection of results centered on the evaluation of physico-chemical stability, toxicity, bio-distribution and excretion mechanisms of Gd2O2S:Ln3+ nanoparticles intravenously injected in rats. Two formulations are here tested with a common matrix and different dopants: Gd2O2S:Eu3+5% and Gd2O2S:Yb3+4%/Tm3+0.1%. The NPs appear to be almost insoluble in pure water and human plasma but corrosion/degradation phenomenon appears in acidic conditions classically encountered in cell lysosomes. Whole body in vivo distribution, excretion and toxicity evaluation revealed a high tolerance of nanoparticles with a long-lasting imaging signal associated with a slow hepatobiliary clearance and very weak urinary excretion. The results show that the majority of the injected product (>60%) has been excreted through the feces after five months. Experiments have evidenced that the NPs mainly accumulate in macrophage-rich organs, that is mainly liver and spleen and to a lesser extent lungs and bones (mainly marrow). No significant amounts have been detected in other organs such as heart, kidneys, brain, intestine and skin. Gd2O2S:Ln3+ NPs appeared to be very well tolerated up to 400 mg/kg when administered intravenously. Statement of SignificanceSince 2011, we have focused our work on Gd2O2S nanoparticles (NPs) for multimodal bioimaging using fluorescence, Magnetic Resonance Imaging (MRI) and Computed Tomography with very efficient results already published. However, since the European Medicines Agency has concluded its review of gadolinium contrast agents, confirming recommendations to restrict the use of some linear gadolinium agents used in MRI, a particular attention must be paid to any new contrast media containing gadolinium. Therefore, we present in this paper a compilation of studies about toxicity, bio-distribution and excretion mechanisms of Gd2O2S:Ln3+ NPs intravenously injected into rats. We also present an in vitro kinetic study of NPs degradation in aqueous and biological media to provide some information on chemical and biological stability.

The selective electrochemical sensing of dopamine at a polypyrrole film doped with an anionic β−cyclodextrin

Pyrrole was electropolymerised in a 0.01 M sulfonated β−cyclodextrin solution to generate an adherent polypyrrole film doped with the anionic sulfonated β−cyclodextrin, PPy−SβCD. This polymeric material was used as an electrochemical sensor for the detection of dopamine (DA), and compared with the sensing abilities of polypyrrole doped with several more common anionic dopants. The sensing performance of the PPy−SβCD film was significantly better, with a linear calibration curve extending to 50 μM, with a sensitivity of 0.90 μA μM−1 cm−2 and a detection limit of 1.0 × 10−6 M. Excellent selectivity was achieved and no interference was observed from a range of interference compounds, including ascorbic acid, uric acid, aspartic acid, acetylcholine, aminobutyric acid, glutamic acid, glycine, histamine, acetaminophenol 5−hydroxytryptamine and 5−hydroxyindole acetic acid. However, interference was seen with the structurally−related epinephrine (Ep) and 3,4−dihydroxyphenylacetic acid (DOPAC), with the oxidation of DA, Ep and DOPAC occurring at similar potentials. The good selectivity in the presence of the other interference species was attributed to an interaction between the cyclodextrin dopant and the protonated DA molecule which was evident when data were fitted to Michaelis−Menten and Lineweaver−Burk kinetics.

Tuning the Optical and Electrical Properties of Few-Layer Black Phosphorus via Physisorption of Small Solvent Molecules.

Black phosphorus (BP) is recently becoming more and more popular among semiconducting 2D materials for (opto)electronic applications. The controlled physisorption of molecules on the BP surface is a viable approach to modulate its optical and electronic properties. Solvents consisting of small molecules are often used for washing 2D materials or as liquid media for their chemical functionalization with larger molecules, disregarding their ability to change the opto-electronic properties of BP. Herein, it is shown that the opto-electronic properties of mechanically exfoliated few-layer BP are altered when physically interacting with common solvents. Significantly, charge transport analysis in field-effect transistors reveals that physisorbed solvent molecules induce a modulation of the charge carrier density which can be as high as 1012 cm-2 in BP, i.e., comparable to common dopants such as F4 -TCNQ and MoO3 . By combining experimental evidences with density functional theory calculations, it is confirmed that BP doping by solvent molecules not only depends on charge transfer, but is also influenced by molecular dipole. The results clearly demonstrate how an exquisite tuning of the opto-electronic properties of few-layer BP can be achieved through physisorption of small solvent molecules. Such findings are of interest both for fundamental studies and more technological applications in opto-electronics.

Multimodal Gadolinium Oxysulfide Nanoparticles for Bioimaging: A Comprehensive Biodistribution, Elimination and Toxicological Study

For some years now, gadolinium oxysulfide nanoparticles (NPs) appear as strong candidates for very efficient multimodal in vivo imaging by: 1) Magnetic Resonance (MRI), 2) X-ray Computed Tomography (CT) and 3) photoluminescence imaging. In this paper, we present a selection of results centered on the evaluation of physico-chemical stability, toxicity, bio-distribution and excretion mechanisms of Gd2O2S:Ln3+ nanoparticles intravenously injected in rats. Two formulations are here tested with a common matrix and different dopants: Gd2O2S:Eu3+5% and Gd2O2S:Yb3+4%/Tm3+0.1%. The NPs appear to be almost insoluble in pure water and human plasma but corrosion/degradation phenomenon appears in acidic conditions classically encountered in cell lysosomes. Whole body in vivo distribution, excretion and toxicity evaluation revealed a high tolerance of nanoparticles with a long-lasting imaging signal associated with a slow hepatobiliary clearance and very weak urinary excretion. The results show that the majority of the injected product (> 60%) has been excreted through the feces after five months. Experiments have evidenced that the NPs mainly accumulate in macrophage-rich organs, that is mainly liver and spleen and to a lesser extent lungs and bones (mainly marrow). No significant amounts have been detected in other organs such as heart, kidneys, brain, intestine and skin. Gd2O2S:Ln3+ NPs appeared to be very well tolerated up to 400 mg/kg when administered intravenously.

Polar Side Chains Enhance Processability, Electrical Conductivity, and Thermal Stability of a Molecularly p-Doped Polythiophene.

Molecular doping of organic semiconductors is critical for optimizing a range of optoelectronic devices such as field-effect transistors, solar cells, and thermoelectric generators. However, many dopant:polymer pairs suffer from poor solubility in common organic solvents, which leads to a suboptimal solid-state nanostructure and hence low electrical conductivity. A further drawback is the poor thermal stability through sublimation of the dopant. The use of oligo ethylene glycol side chains is demonstrated to significantly improve the processability of the conjugated polymer p(g4 2T-T)-a polythiophene-in polar aprotic solvents, which facilitates coprocessing of dopant:polymer pairs from the same solution at room temperature. The use of common molecular dopants such as 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is explored. Doping of p(g4 2T-T) with F4TCNQ results in an electrical conductivity of up to 100 S cm-1 . Moreover, the increased compatibility of the polar dopant F4TCNQ with the oligo ethylene glycol functionalized polythiophene results in a high degree of thermal stability at up to 150 °C.

Atomic Adsorption on Nitrogenated Holey Graphene

Two-dimensional (2D) crystals with C2N stoichiometry have recently been synthesized. This novel material, dubbed nitrogenated holey graphene (NHG), is a semiconductor unlike pristine graphene. For any novel material, it is fundamental to understand the behaviors of different adatoms on its surface, a process responsible for a rich phenomenology. In this work, we employed first-principles calculations and a hybrid quantum mechanics/molecular mechanics method to investigate the adsorption of H, B, and O on NHG sheets. The adsorption of H atoms could prove important for applications in hydrogen storage and gas sensors, whereas the adsorption of O in any new material is important to understand its oxidation process. Both N and B are common dopants in carbon-based systems, such as in BNC structures. We found that H and B prefer to adsorb on top of a nitrogen atom, whereas O prefers to adsorb on top of a carbon–carbon bond. The electronic structure of NHG also changes as a result of the presence of adatoms, wit...

Conflicting Roles of Anion Doping on the Electrochemical Performance of Li-Ion Battery Cathode Materials

Anion doping is one of the most widely adopted strategies to improve the electrochemical performance of cathode materials for Li-ion batteries. However, undesirable side effects are often observed together with enhanced electrochemical properties, leading to an unsatisfactory overall performance. In order to develop an anion doping strategy which enhances the positive effects and suppresses undesirable side effects, the understanding of their origin at the atomic scale is a crucial step. In this work, using density functional theory (DFT), we report a systematic study on the effects of three common anion dopants (F, S, Cl) on a wide range of properties of a model cathode material, LiNiO2, including redox potential, ionic conductivity, Li/Ni exchange, lattice distortion, and Ni migration upon delithiation. The results show that the dopants improve certain properties but worsen others, revealing some distance-dependent features. Overall, our work shows conflicting roles of anion doping on the battery voltag...

Factors limiting doping efficiency of Iridium in pulsed laser deposited TiO2 transparent conducting oxide

High transmittance and low resistivity make doped TiO2 films outstanding electrodes for use in optoelectronic devices operating in the infra-red region. In this work, we studied the impact of Ir doping in TiO2 thin films on the optoelectrical properties. High-quality nanocrystalline Ti1−xIrxO2 thin films ~60 nm thick were grown by pulsed laser deposition from an Ir-doped target (x = 0–0.15 wt%). Films were deposited on quartz glass at a base pressure of 2 × 10−3 Pa and a substrate temperature of 780 K. The resistivity of the films decreased by 3 orders of magnitude when x increased from 0 to 0.10. The carrier mobility and concentrations increased by a factor of 2.55 from 18 to 46 cm2 V−1 s−1 at 5 %, and rose by ~2 orders of magnitude from 1019 to 1021 cm−3 at 15 % Ir, respectively. Optimal film properties were measured to be at x = 0.10, where resistivity, mobility, and carrier concentrations were 5 × 10−4 Ω cm, 32 cm2 V−1 s−1, and 1020 cm−3, respectively. The highest observed doping efficiency was ~1.1 which is similar to common dopants. At the same time, film transmittance was measured to be above 80 % in the visible and infrared regions, suitable for use in both spectral regimes. The films were characterized by X-ray diffraction, Hall transport, optical transmission, and Raman spectroscopy.