A series of Yb：Tm：LiNbO_3 crystals doped with x mol% Hf^（4＋）ions（x = 2, 4, and 6） were grown by the Czochralski method. The dopant occupancy and defect structure of Hf：Yb：Tm：LiNbO_3 crystals were investigate...A series of Yb：Tm：LiNbO_3 crystals doped with x mol% Hf^（4＋）ions（x = 2, 4, and 6） were grown by the Czochralski method. The dopant occupancy and defect structure of Hf：Yb：Tm：LiNbO_3 crystals were investigated by x-ray diffraction and infrared transmission spectra. The influence of Hf^（4＋）ions concentration on UV–VIS–NIR absorption spectra of Hf：Yb：Tm：LiNbO_3 crystals was discussed. The upconversion luminescence of Hf：Yb：Tm：LiNbO_3 crystals was obtained under 980 nm excitation. Strong emissions were observed at 475 nm in the blue wavelength range and 651 nm in the red wavelength range. Remarkably, enhancement of the red and blue upconversion luminescence was achieved by tridoping Hf^（4＋）ions.展开更多
Nanomaterials with low-dimensional morphology have been explored for enhancing the performance of strain sensors,but it remains difficult to achieve high stretchability and sensitivity simultaneously.In this work,a co...Nanomaterials with low-dimensional morphology have been explored for enhancing the performance of strain sensors,but it remains difficult to achieve high stretchability and sensitivity simultaneously.In this work,a composite structure strain sensor based on nanomaterials and conductive liquid is designed,demonstrated,and engineered.The nanowire-microfluidic hybrid(NMH)strain sensor responds to multiscale strains from 4%to over 400%,with a high sensitivity and durability under small strain.Metal nanowires and carbon nanotubes are used to fabricate the NMH strain sensors,which simultaneously exhibit record-high average gauge factors and stretchability,far better than the conventional nanowire devices.Quantitative modeling of the electrical characteristics reveals that the effective conductivity percolation through the hybrid structures is the key to achieving high gauge factors for multiscale sensing.The sensors can operate at low voltages and are capable of responding to various mechanical deformations.When fixed on human skin,the sensors can monitor large-scale deformations(skeleton motion)and small-scale deformations(facial expressions and pulses).The sensors are also employed in multichannel,interactive electronic system for wireless control of robotics.Such demonstrations indicate the potential of the sensors as wearable detectors for human motion or as bionic ligaments in soft robotics.展开更多
基金Project supported by Special Funds of Harbin Innovation Talents in Science and Technology Research,China(Grant No.2015RQQXJ045)Science Funds for the Young Innovative Talents of HUST,China
文摘A series of Yb：Tm：LiNbO_3 crystals doped with x mol% Hf^（4＋）ions（x = 2, 4, and 6） were grown by the Czochralski method. The dopant occupancy and defect structure of Hf：Yb：Tm：LiNbO_3 crystals were investigated by x-ray diffraction and infrared transmission spectra. The influence of Hf^（4＋）ions concentration on UV–VIS–NIR absorption spectra of Hf：Yb：Tm：LiNbO_3 crystals was discussed. The upconversion luminescence of Hf：Yb：Tm：LiNbO_3 crystals was obtained under 980 nm excitation. Strong emissions were observed at 475 nm in the blue wavelength range and 651 nm in the red wavelength range. Remarkably, enhancement of the red and blue upconversion luminescence was achieved by tridoping Hf^（4＋）ions.
基金The authors gratefully acknowledge thefinancial support of the Guangdong Natural Science Funds for Distinguished Young Scholars under Grant 2016A030306046the Guangdong Youth Top-notch Talent Support Program(No.2016TQ03X648)the“985”Project(30000-31101200).
文摘Nanomaterials with low-dimensional morphology have been explored for enhancing the performance of strain sensors,but it remains difficult to achieve high stretchability and sensitivity simultaneously.In this work,a composite structure strain sensor based on nanomaterials and conductive liquid is designed,demonstrated,and engineered.The nanowire-microfluidic hybrid(NMH)strain sensor responds to multiscale strains from 4%to over 400%,with a high sensitivity and durability under small strain.Metal nanowires and carbon nanotubes are used to fabricate the NMH strain sensors,which simultaneously exhibit record-high average gauge factors and stretchability,far better than the conventional nanowire devices.Quantitative modeling of the electrical characteristics reveals that the effective conductivity percolation through the hybrid structures is the key to achieving high gauge factors for multiscale sensing.The sensors can operate at low voltages and are capable of responding to various mechanical deformations.When fixed on human skin,the sensors can monitor large-scale deformations(skeleton motion)and small-scale deformations(facial expressions and pulses).The sensors are also employed in multichannel,interactive electronic system for wireless control of robotics.Such demonstrations indicate the potential of the sensors as wearable detectors for human motion or as bionic ligaments in soft robotics.
