Design Strategy for Improving Optical and Electrical Properties and Stability of Lead-Halide Semiconductors

Broad absorption, long-lived photogenerated carriers, high conductance, and high stability are all required for a light absorber toward its real application on solar cells. Inorganic–organic hybrid lead-halide materials have shown tremendous potential for applications in solar cells. This work offers a new design strategy to improve the absorption range, conductance, photoconductance, and stability of these materials. We synthesized a new photochromic lead-chloride semiconductor by incorporating a photoactive viologen zwitterion into a lead-chloride system in the coordinating mode. This semiconductor has a novel inorganic–organic hybrid structure, where 1-D semiconducting inorganic lead-chloride nanoribbons covalently bond to 1-D semiconducting organic π-aggregates. It shows high stability against light, heat, and moisture. After photoinduced electron transfer (PIET), it yields a long-lived charge-separated state with a broad absorption band covering the 200–900 nm region while increasing its conductance and photoconductance. This work is the first to modify the photoconductance of semiconductors by PIET. The observed increasing times of conductivity reached 3 orders of magnitude, which represents a record for photoswitchable semiconductors. The increasing photocurrent comes mainly from the semiconducting organic π-aggregates, which indicates a chance to improve the photocurrent by modifying the organic component. These findings contribute to the exploration of light absorbers for solar cells

Design Strategy for Improving Optical and Electrical Properties and Stability of Lead-Halide Semiconductors

Broad absorption, long-lived photogenerated carriers, high conductance, and high stability are all required for a light absorber toward its real application on solar cells. Inorganic–organic hybrid lead-halide materials have shown tremendous potential for applications in solar cells. This work offers a new design strategy to improve the absorption range, conductance, photoconductance, and stability of these materials. We synthesized a new photochromic lead-chloride semiconductor by incorporating a photoactive viologen zwitterion into a lead-chloride system in the coordinating mode. This semiconductor has a novel inorganic–organic hybrid structure, where 1-D semiconducting inorganic lead-chloride nanoribbons covalently bond to 1-D semiconducting organic π-aggregates. It shows high stability against light, heat, and moisture. After photoinduced electron transfer (PIET), it yields a long-lived charge-separated state with a broad absorption band covering the 200–900 nm region while increasing its conductance and photoconductance. This work is the first to modify the photoconductance of semiconductors by PIET. The observed increasing times of conductivity reached 3 orders of magnitude, which represents a record for photoswitchable semiconductors. The increasing photocurrent comes mainly from the semiconducting organic π-aggregates, which indicates a chance to improve the photocurrent by modifying the organic component. These findings contribute to the exploration of light absorbers for solar cells

Design Strategy for Improving Optical and Electrical Properties and Stability of Lead-Halide Semiconductors

Broad absorption, long-lived photogenerated carriers, high conductance, and high stability are all required for a light absorber toward its real application on solar cells. Inorganic–organic hybrid lead-halide materials have shown tremendous potential for applications in solar cells. This work offers a new design strategy to improve the absorption range, conductance, photoconductance, and stability of these materials. We synthesized a new photochromic lead-chloride semiconductor by incorporating a photoactive viologen zwitterion into a lead-chloride system in the coordinating mode. This semiconductor has a novel inorganic–organic hybrid structure, where 1-D semiconducting inorganic lead-chloride nanoribbons covalently bond to 1-D semiconducting organic π-aggregates. It shows high stability against light, heat, and moisture. After photoinduced electron transfer (PIET), it yields a long-lived charge-separated state with a broad absorption band covering the 200–900 nm region while increasing its conductance and photoconductance. This work is the first to modify the photoconductance of semiconductors by PIET. The observed increasing times of conductivity reached 3 orders of magnitude, which represents a record for photoswitchable semiconductors. The increasing photocurrent comes mainly from the semiconducting organic π-aggregates, which indicates a chance to improve the photocurrent by modifying the organic component. These findings contribute to the exploration of light absorbers for solar cells

Cation-Induced Strategy toward an Hourglass-Shaped Cu₆I₇^– Cluster and Its Color-Tunable Luminescence

We have designed and synthesized a series of two-dimensional materials featuring with a (3,6)-connected <b>kgd</b> layer, in which an unprecedented anionic Cu₆I₇^– cluster was first trapped through a cation-induced synthetic strategy. The emission colors of these cluster-based luminophores gradually shift from blue to yellow as the monovalent cations (Li⁺, Na⁺, NH₄⁺, K⁺, TEA⁺) located between the neighboring layers changed. SCXRD analyses discover that the variation of the emission may be attributed to the transformation of the hourglass-shaped Cu₆I₇^– cluster. The bright, tunable, and broad luminescent emissions make them promising candidates as phosphors for light-emitting diodes (LEDs). Particularly, compound <b>1-TEA</b> emitting intensive yellow light with high luminescence quantum efficiency (QY = 79.9%) shows extremely high thermal, pH, organic solvent, and mechanical photostabilities. By employing it as a yellow phosphor, we fabricate a series of white lighting materials with high color rendering index (CRI)

Nitrogen-Rich Tetranuclear Metal Complex as a New Structural Motif for Energetic Materials

For designing energetic materials (EMs), the most challenging issue is to achieve a balance between energetic performance and reliable stability. In this work, we employed an efficient and convenient method to synthesize a new class of EMs: nitrogen-rich tetranuclear metal complexes [M­(Hdtim)­(H₂O)₂]₄ (M = Zn <b>1</b>, Mn <b>2</b>; H₃dtim = 1<i>H</i>-imidazol-4,5-tetrazole) with the N content of >46%. The structural analyses illustrate that isomorphous compounds <b>1</b> and <b>2</b> feature isolated hollow ellipsoid tetranuclear units, which are linked by both π–π interactions and hydrogen-bonding interactions to give a 3D supramolecular architecture. Compounds <b>1</b> and <b>2</b> exhibit prominent energetic characteristics: excellent detonation performances and reliable thermal, impact, and friction stabilities. Being nitrogen-rich tetrazolate compounds, the enthalpies of combustion of <b>1</b> (−11.570 kJ g^–1) and <b>2</b> (−12.186 kJ g^–1) are higher than those of classical EMs, RDX and HMX, and they possess high positive heats of formation. Sensitivity tests demonstrate that <b>1</b> and <b>2</b> are insensitive to external mechanical action. Excellent energetic performances and low sensitivities promote <b>1</b> and <b>2</b> to serve as a new class of promising EMs with a desirable level of safety

Nitrogen-Rich Tetranuclear Metal Complex as a New Structural Motif for Energetic Materials

For designing energetic materials (EMs), the most challenging issue is to achieve a balance between energetic performance and reliable stability. In this work, we employed an efficient and convenient method to synthesize a new class of EMs: nitrogen-rich tetranuclear metal complexes [M­(Hdtim)­(H₂O)₂]₄ (M = Zn <b>1</b>, Mn <b>2</b>; H₃dtim = 1<i>H</i>-imidazol-4,5-tetrazole) with the N content of >46%. The structural analyses illustrate that isomorphous compounds <b>1</b> and <b>2</b> feature isolated hollow ellipsoid tetranuclear units, which are linked by both π–π interactions and hydrogen-bonding interactions to give a 3D supramolecular architecture. Compounds <b>1</b> and <b>2</b> exhibit prominent energetic characteristics: excellent detonation performances and reliable thermal, impact, and friction stabilities. Being nitrogen-rich tetrazolate compounds, the enthalpies of combustion of <b>1</b> (−11.570 kJ g^–1) and <b>2</b> (−12.186 kJ g^–1) are higher than those of classical EMs, RDX and HMX, and they possess high positive heats of formation. Sensitivity tests demonstrate that <b>1</b> and <b>2</b> are insensitive to external mechanical action. Excellent energetic performances and low sensitivities promote <b>1</b> and <b>2</b> to serve as a new class of promising EMs with a desirable level of safety

Nitrogen-Rich Tetranuclear Metal Complex as a New Structural Motif for Energetic Materials

For designing energetic materials (EMs), the most challenging issue is to achieve a balance between energetic performance and reliable stability. In this work, we employed an efficient and convenient method to synthesize a new class of EMs: nitrogen-rich tetranuclear metal complexes [M­(Hdtim)­(H₂O)₂]₄ (M = Zn <b>1</b>, Mn <b>2</b>; H₃dtim = 1<i>H</i>-imidazol-4,5-tetrazole) with the N content of >46%. The structural analyses illustrate that isomorphous compounds <b>1</b> and <b>2</b> feature isolated hollow ellipsoid tetranuclear units, which are linked by both π–π interactions and hydrogen-bonding interactions to give a 3D supramolecular architecture. Compounds <b>1</b> and <b>2</b> exhibit prominent energetic characteristics: excellent detonation performances and reliable thermal, impact, and friction stabilities. Being nitrogen-rich tetrazolate compounds, the enthalpies of combustion of <b>1</b> (−11.570 kJ g^–1) and <b>2</b> (−12.186 kJ g^–1) are higher than those of classical EMs, RDX and HMX, and they possess high positive heats of formation. Sensitivity tests demonstrate that <b>1</b> and <b>2</b> are insensitive to external mechanical action. Excellent energetic performances and low sensitivities promote <b>1</b> and <b>2</b> to serve as a new class of promising EMs with a desirable level of safety

Coordination Polymerization of Metal Azides and Powerful Nitrogen-Rich Ligand toward Primary Explosives with Excellent Energetic Performances

Advancement in explosive systems toward miniaturization and enhanced safety has prompted the development of primary explosives with powerful detonation performance and relatively low sensitivities. Energetic coordination polymers (ECPs) as a new type of energetic materials have attracted wide attention. However, regulating the energetic characters of ECPs and establishing the relationship between structure and energetic property remains great challenges. In this study, two isomorphic 2D π-stacked solvent-free coordination polymers, [M­(N₃)₂(atrz)]_<i>n</i> (M = Co <b>1</b>, Cd <b>2</b>; atrz = 4,4′-azo-1,2,4-triazole), were hydrothermally prepared and structurally characterized by X-ray diffraction. The two compounds exhibit reliable stabilities, remarkable positive enthalpies of formation, and prominent heats of detonation. The enthalpy of formation of <b>1</b> is 4.21 kJ·g^–1, which is higher than those of all hitherto known primary explosives. Repulsive steric clashes between the sensitive azide ions in <b>1</b> and <b>2</b> influence the mechanical sensitivities deduced from the calculated noncovalent interaction domains. The two energetic π-stacked ECPs <b>1</b> and <b>2</b> can serve as candidates for primary explosives with an approved level of safety

Coordination Polymerization of Metal Azides and Powerful Nitrogen-Rich Ligand toward Primary Explosives with Excellent Energetic Performances

Advancement in explosive systems toward miniaturization and enhanced safety has prompted the development of primary explosives with powerful detonation performance and relatively low sensitivities. Energetic coordination polymers (ECPs) as a new type of energetic materials have attracted wide attention. However, regulating the energetic characters of ECPs and establishing the relationship between structure and energetic property remains great challenges. In this study, two isomorphic 2D π-stacked solvent-free coordination polymers, [M­(N₃)₂(atrz)]_<i>n</i> (M = Co <b>1</b>, Cd <b>2</b>; atrz = 4,4′-azo-1,2,4-triazole), were hydrothermally prepared and structurally characterized by X-ray diffraction. The two compounds exhibit reliable stabilities, remarkable positive enthalpies of formation, and prominent heats of detonation. The enthalpy of formation of <b>1</b> is 4.21 kJ·g^–1, which is higher than those of all hitherto known primary explosives. Repulsive steric clashes between the sensitive azide ions in <b>1</b> and <b>2</b> influence the mechanical sensitivities deduced from the calculated noncovalent interaction domains. The two energetic π-stacked ECPs <b>1</b> and <b>2</b> can serve as candidates for primary explosives with an approved level of safety