For healthy lighting,daily lighting that considers both visible light and near-infrared(NIR)light is necessary.However,at~900 nm,the extensively used solar-like phosphor-converted light-emitting diodes(pc-LEDs)are lim...For healthy lighting,daily lighting that considers both visible light and near-infrared(NIR)light is necessary.However,at~900 nm,the extensively used solar-like phosphor-converted light-emitting diodes(pc-LEDs)are limited by a lack of high-performance NIR luminescent materials.We report a broadband NIR phosphor Sr_(2)ScSbO_(6):Cr^(3+) with a double perovskite-type structure,thus simultaneously demonstrating high luminescence efficiency and good thermal stability.Under 550-nm excitation,Sr_(2)ScSbO_(6):Cr^(3+) demonstrates broadband NIR emission centered at~890 nm with luminescence internal/external efficiencies of 82.0%/35.7%,respectively.Furthermore,the luminescence integrated intensity at 430 K remains at~66.4% of the initial intensity.We successfully fabricated pc-LED devices using a 465-nm-sized blue chip and other commercial phosphors,presenting a relatively complete solar-like spectrum from blue to NIR light and is expected to be used in solar-like lighting.展开更多
Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical ...Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical water splitting systems because of their high theoretical solar-to-hydrogen efficiencies.Nevertheless,the synthesis of perovskite oxynitride single crystals requires the coupling of cation exchange and ammonization processes,which is exceptionally challenging.The present study demonstrates an inorganic vapor method that provides,for the first time ever,high-quality epitaxial perovskite SrTaO_(2)N single crystals on the centimeter scale.Assessments using Raman spectroscopy,crystal structure analysis and density functional theory determined that the conversion mechanism followed a topotactic transition mode.Compared with conventional SrTaO_(2)N particle-assembled films,the SrTaO_(2)N single crystals made in this work were free of interparticle interfaces and grain boundaries,which exhibited extremely high performance during photoelectrochemical water oxidation.In particular,these SrTaO_(2)N single crystals showed the highest photocurrent density at 0.6 V vs.RHE(1.20 mA cm^(−2)) and the highest photocurrent filling factor(47.6%)reported to date,together with a low onset potential(0.35 V vs.RHE).This onset potential was 200 mV less than that of the reported in situ SrTaO_(2)N film,and the photocurrent fill factor was improved by 2 to 3 times.展开更多
基金supported by the National Natural Science Foundation of China(51972020 and 51832005)。
文摘For healthy lighting,daily lighting that considers both visible light and near-infrared(NIR)light is necessary.However,at~900 nm,the extensively used solar-like phosphor-converted light-emitting diodes(pc-LEDs)are limited by a lack of high-performance NIR luminescent materials.We report a broadband NIR phosphor Sr_(2)ScSbO_(6):Cr^(3+) with a double perovskite-type structure,thus simultaneously demonstrating high luminescence efficiency and good thermal stability.Under 550-nm excitation,Sr_(2)ScSbO_(6):Cr^(3+) demonstrates broadband NIR emission centered at~890 nm with luminescence internal/external efficiencies of 82.0%/35.7%,respectively.Furthermore,the luminescence integrated intensity at 430 K remains at~66.4% of the initial intensity.We successfully fabricated pc-LED devices using a 465-nm-sized blue chip and other commercial phosphors,presenting a relatively complete solar-like spectrum from blue to NIR light and is expected to be used in solar-like lighting.
基金supported by the National Key Research and Development Program of China(2018YFA0209303)the National Natural Science Foundation of China(22025202 and 51972165)Natural Science Foundation of Jiangsu Province(BK20202003)。
文摘Large-scale single crystals have potential applications in many fields,such as in ferroelectric and photoelectric energy conversion devices.Perovskite oxynitrides have also attracted attention in photoelectrochemical water splitting systems because of their high theoretical solar-to-hydrogen efficiencies.Nevertheless,the synthesis of perovskite oxynitride single crystals requires the coupling of cation exchange and ammonization processes,which is exceptionally challenging.The present study demonstrates an inorganic vapor method that provides,for the first time ever,high-quality epitaxial perovskite SrTaO_(2)N single crystals on the centimeter scale.Assessments using Raman spectroscopy,crystal structure analysis and density functional theory determined that the conversion mechanism followed a topotactic transition mode.Compared with conventional SrTaO_(2)N particle-assembled films,the SrTaO_(2)N single crystals made in this work were free of interparticle interfaces and grain boundaries,which exhibited extremely high performance during photoelectrochemical water oxidation.In particular,these SrTaO_(2)N single crystals showed the highest photocurrent density at 0.6 V vs.RHE(1.20 mA cm^(−2)) and the highest photocurrent filling factor(47.6%)reported to date,together with a low onset potential(0.35 V vs.RHE).This onset potential was 200 mV less than that of the reported in situ SrTaO_(2)N film,and the photocurrent fill factor was improved by 2 to 3 times.
