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Oxyhydrides of rare-earth metals (REMOHs) exhibit notable photochromic behaviors. Among these, yttrium oxyhydride (YHO) stands out for its impressive transparency and swift UV-responsive color change, positioning it as an optimal material for self-cleaning window applications. Although semiconductor photocatalysis holds potential solutions for critical environmental issues, optimizing the photocatalytic efficacy of photochromic substances has not been adequately addressed. This research advances the study of REMOHs, focusing on the properties of gadolinium oxyhydride (GdHO) both theoretically and experimentally. The electronic and structural characteristics of GdHO, vital for ceramic technology, are thoroughly examined. Explicitly determined work functions for GdH2, GdHO, and Gd2O3 stand at 3.4 eV, 3.0 eV, and 4.3 eV, respectively. Bader charge analysis showcases GdHO’s intricate bonding attributes, whereas its electron localization function majorly presents an ionic nature. The charge neutrality level is situated about 0.33 eV below the top valence band, highlighting these materials’ inclination for acceptor-dominant electrical conductivity. Remarkably, this research unveils GdHO films’ photocatalytic capabilities for the first time. Even with their restricted surface due to thinness, these films follow the Langmuir–Hinshelwood degradation kinetics, ensuring total degradation of methylene blue in a day. It was observed that GdHO’s work function diminishes with reduced deposition pressure, and UV exposure further decreases it by 0.2 eV—a change that reverts post-UV exposure. The persistent stability of GdHO films, hinting at feasible recyclability, enhances their potential efficiency, underlining their viability in practical applications. Overall, this study accentuates GdHO’s pivotal role in electronics and photocatalysis, representing a landmark advancement in the domain.

Oxyhydrides of rare-earth metals (REMOHs) exhibit notable photochromic behaviors. Among these, yttrium oxyhydride (YHO) stands out for its impressive transparency and swift UV-responsive color change, positioning it as an optimal material for self-cleaning window applications. Although semiconductor photocatalysis holds potential solutions for critical environmental issues, optimizing the photocatalytic efficacy of photochromic substances has not been adequately addressed. This research advances the study of REMOHs, focusing on the properties of gadolinium oxyhydride (GdHO) both theoretically and experimentally. The electronic and structural characteristics of GdHO, vital for ceramic technology, are thoroughly examined. Explicitly determined work functions for GdH2, GdHO, and Gd2O3 stand at 3.4 eV, 3.0 eV, and 4.3 eV, respectively. Bader charge analysis showcases GdHO’s intricate bonding attributes, whereas its electron localization function majorly presents an ionic nature. The charge neutrality level is situated about 0.33 eV below the top valence band, highlighting these materials’ inclination for acceptor-dominant electrical conductivity. Remarkably, this research unveils GdHO films’ photocatalytic capabilities for the first time. Even with their restricted surface due to thinness, these films follow the Langmuir–Hinshelwood degradation kinetics, ensuring total degradation of methylene blue in a day. It was observed that GdHO’s work function diminishes with reduced deposition pressure, and UV exposure further decreases it by 0.2 eV—a change that reverts post-UV exposure. The persistent stability of GdHO films, hinting at feasible recyclability, enhances their potential efficiency, underlining their viability in practical applications. Overall, this study accentuates GdHO’s pivotal role in electronics and photocatalysis, representing a landmark advancement in the domain.

Oxyhydrides of rare-earth metals (REMOHs) exhibit notable photochromic behaviors. Among these, yttrium oxyhydride (YHO) stands out for its impressive transparency and swift UV-responsive color change, positioning it as an optimal material for self-cleaning window applications. Although semiconductor photocatalysis holds potential solutions for critical environmental issues, optimizing the photocatalytic efficacy of photochromic substances has not been adequately addressed. This research advances the study of REMOHs, focusing on the properties of gadolinium oxyhydride (GdHO) both theoretically and experimentally. The electronic and structural characteristics of GdHO, vital for ceramic technology, are thoroughly examined. Explicitly determined work functions for GdH2, GdHO, and Gd2O3 stand at 3.4 eV, 3.0 eV, and 4.3 eV, respectively. Bader charge analysis showcases GdHO’s intricate bonding attributes, whereas its electron localization function majorly presents an ionic nature. The charge neutrality level is situated about 0.33 eV below the top valence band, highlighting these materials’ inclination for acceptor-dominant electrical conductivity. Remarkably, this research unveils GdHO films’ photocatalytic capabilities for the first time. Even with their restricted surface due to thinness, these films follow the Langmuir–Hinshelwood degradation kinetics, ensuring total degradation of methylene blue in a day. It was observed that GdHO’s work function diminishes with reduced deposition pressure, and UV exposure further decreases it by 0.2 eV—a change that reverts post-UV exposure. The persistent stability of GdHO films, hinting at feasible recyclability, enhances their potential efficiency, underlining their viability in practical applications. Overall, this study accentuates GdHO’s pivotal role in electronics and photocatalysis, representing a landmark advancement in the domain.

Oxyhydrides of rare-earth metals (REMOHs) exhibit notable photochromic behaviors. Among these, yttrium oxyhydride (YHO) stands out for its impressive transparency and swift UV-responsive color change, positioning it as an optimal material for self-cleaning window applications. Although semiconductor photocatalysis holds potential solutions for critical environmental issues, optimizing the photocatalytic efficacy of photochromic substances has not been adequately addressed. This research advances the study of REMOHs, focusing on the properties of gadolinium oxyhydride (GdHO) both theoretically and experimentally. The electronic and structural characteristics of GdHO, vital for ceramic technology, are thoroughly examined. Explicitly determined work functions for GdH2, GdHO, and Gd2O3 stand at 3.4 eV, 3.0 eV, and 4.3 eV, respectively. Bader charge analysis showcases GdHO’s intricate bonding attributes, whereas its electron localization function majorly presents an ionic nature. The charge neutrality level is situated about 0.33 eV below the top valence band, highlighting these materials’ inclination for acceptor-dominant electrical conductivity. Remarkably, this research unveils GdHO films’ photocatalytic capabilities for the first time. Even with their restricted surface due to thinness, these films follow the Langmuir–Hinshelwood degradation kinetics, ensuring total degradation of methylene blue in a day. It was observed that GdHO’s work function diminishes with reduced deposition pressure, and UV exposure further decreases it by 0.2 eV—a change that reverts post-UV exposure. The persistent stability of GdHO films, hinting at feasible recyclability, enhances their potential efficiency, underlining their viability in practical applications. Overall, this study accentuates GdHO’s pivotal role in electronics and photocatalysis, representing a landmark advancement in the domain.

Oxyhydrides of rare-earth metals (REMOHs) exhibit notable photochromic behaviors. Among these, yttrium oxyhydride (YHO) stands out for its impressive transparency and swift UV-responsive color change, positioning it as an optimal material for self-cleaning window applications. Although semiconductor photocatalysis holds potential solutions for critical environmental issues, optimizing the photocatalytic efficacy of photochromic substances has not been adequately addressed. This research advances the study of REMOHs, focusing on the properties of gadolinium oxyhydride (GdHO) both theoretically and experimentally. The electronic and structural characteristics of GdHO, vital for ceramic technology, are thoroughly examined. Explicitly determined work functions for GdH2, GdHO, and Gd2O3 stand at 3.4 eV, 3.0 eV, and 4.3 eV, respectively. Bader charge analysis showcases GdHO’s intricate bonding attributes, whereas its electron localization function majorly presents an ionic nature. The charge neutrality level is situated about 0.33 eV below the top valence band, highlighting these materials’ inclination for acceptor-dominant electrical conductivity. Remarkably, this research unveils GdHO films’ photocatalytic capabilities for the first time. Even with their restricted surface due to thinness, these films follow the Langmuir–Hinshelwood degradation kinetics, ensuring total degradation of methylene blue in a day. It was observed that GdHO’s work function diminishes with reduced deposition pressure, and UV exposure further decreases it by 0.2 eV—a change that reverts post-UV exposure. The persistent stability of GdHO films, hinting at feasible recyclability, enhances their potential efficiency, underlining their viability in practical applications. Overall, this study accentuates GdHO’s pivotal role in electronics and photocatalysis, representing a landmark advancement in the domain.

When exposed to air, metallic yttrium dihydride YH2 films turn into insulating and transparent yttrium oxyhydride (YHO). The incorporation of oxygen causes the lattice expansion of YH2 and the emergence of photochromic properties, i.e., YHO darkens reversibly when illuminated with light of adequate energy and intensity. However, the adequate bleaching of the photodarkened samples once the illumination has stopped is much faster in air than in inert atmosphere. According to this experimental evidence, the photochromic mechanism has to be related to an oxygen diffusion and exchange process. Since this process is accompanied by a lattice expansion/contraction, it can be said that YHO "breathes" when subjected to illumination/darkness cycling. Another interesting side effect of the breathing is the unexpected enhancement of the hydrophobicity of the YHO samples under illumination. A theoretical model able to explain the breathing in YHO is presented, together with the discussion of other alternative explanations.

We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H-2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.

When exposed to air, metallic yttrium dihydride YH2 films turn into insulating and transparent yttrium oxyhydride (YHO). The incorporation of oxygen causes the lattice expansion of YH2 and the emergence of photochromic properties, i.e., YHO darkens reversibly when illuminated with light of adequate energy and intensity. However, the adequate bleaching of the photodarkened samples once the illumination has stopped is much faster in air than in inert atmosphere. According to this experimental evidence, the photochromic mechanism has to be related to an oxygen diffusion and exchange process. Since this process is accompanied by a lattice expansion/contraction, it can be said that YHO "breathes" when subjected to illumination/darkness cycling. Another interesting side effect of the breathing is the unexpected enhancement of the hydrophobicity of the YHO samples under illumination. A theoretical model able to explain the breathing in YHO is presented, together with the discussion of other alternative explanations.

When exposed to air, metallic yttrium dihydride YH2 films turn into insulating and transparent yttrium oxyhydride (YHO). The incorporation of oxygen causes the lattice expansion of YH2 and the emergence of photochromic properties, i.e., YHO darkens reversibly when illuminated with light of adequate energy and intensity. However, the adequate bleaching of the photodarkened samples once the illumination has stopped is much faster in air than in inert atmosphere. According to this experimental evidence, the photochromic mechanism has to be related to an oxygen diffusion and exchange process. Since this process is accompanied by a lattice expansion/contraction, it can be said that YHO "breathes" when subjected to illumination/darkness cycling. Another interesting side effect of the breathing is the unexpected enhancement of the hydrophobicity of the YHO samples under illumination. A theoretical model able to explain the breathing in YHO is presented, together with the discussion of other alternative explanations.

We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H-2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.

We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H-2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.

When exposed to air, metallic yttrium dihydride YH2 films turn into insulating and transparent yttrium oxyhydride (YHO). The incorporation of oxygen causes the lattice expansion of YH2 and the emergence of photochromic properties, i.e., YHO darkens reversibly when illuminated with light of adequate energy and intensity. However, the adequate bleaching of the photodarkened samples once the illumination has stopped is much faster in air than in inert atmosphere. According to this experimental evidence, the photochromic mechanism has to be related to an oxygen diffusion and exchange process. Since this process is accompanied by a lattice expansion/contraction, it can be said that YHO "breathes" when subjected to illumination/darkness cycling. Another interesting side effect of the breathing is the unexpected enhancement of the hydrophobicity of the YHO samples under illumination. A theoretical model able to explain the breathing in YHO is presented, together with the discussion of other alternative explanations.

When exposed to air, metallic yttrium dihydride YH2 films turn into insulating and transparent yttrium oxyhydride (YHO). The incorporation of oxygen causes the lattice expansion of YH2 and the emergence of photochromic properties, i.e., YHO darkens reversibly when illuminated with light of adequate energy and intensity. However, the adequate bleaching of the photodarkened samples once the illumination has stopped is much faster in air than in inert atmosphere. According to this experimental evidence, the photochromic mechanism has to be related to an oxygen diffusion and exchange process. Since this process is accompanied by a lattice expansion/contraction, it can be said that YHO "breathes" when subjected to illumination/darkness cycling. Another interesting side effect of the breathing is the unexpected enhancement of the hydrophobicity of the YHO samples under illumination. A theoretical model able to explain the breathing in YHO is presented, together with the discussion of other alternative explanations.

We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H-2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.

When exposed to air, metallic yttrium dihydride YH2 films turn into insulating and transparent yttrium oxyhydride (YHO). The incorporation of oxygen causes the lattice expansion of YH2 and the emergence of photochromic properties, i.e., YHO darkens reversibly when illuminated with light of adequate energy and intensity. However, the adequate bleaching of the photodarkened samples once the illumination has stopped is much faster in air than in inert atmosphere. According to this experimental evidence, the photochromic mechanism has to be related to an oxygen diffusion and exchange process. Since this process is accompanied by a lattice expansion/contraction, it can be said that YHO "breathes" when subjected to illumination/darkness cycling. Another interesting side effect of the breathing is the unexpected enhancement of the hydrophobicity of the YHO samples under illumination. A theoretical model able to explain the breathing in YHO is presented, together with the discussion of other alternative explanations.

We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H-2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.