Bi doped n-type SnSe thin films were prepared by chemical vapor deposition(CVD)and their structure and thermoelectric properties were studied.The x-ray diffraction patterns,x-ray photoelectron spectroscopy,and microsc...Bi doped n-type SnSe thin films were prepared by chemical vapor deposition(CVD)and their structure and thermoelectric properties were studied.The x-ray diffraction patterns,x-ray photoelectron spectroscopy,and microscopic images show that the prepared SnSe thin films were composed of pure SnSe crystals.The Seebeck coefficients of the Bi-doped SnSe were greatly improved compared to that of undoped SnSe thin films.Specifically,Sn_(0.99)Bi_(0.01)Se thin film exhibited a Seebeck coefficient of905.8μV·K^(-1) at 600 K,much higher than 285.5μV·K^(-1) of undoped SnSe thin film.Further first-principles calculations reveal that the enhancement of the thermoelectric properties can be explained mainly by the Fermi level lifting and the carrier pockets increasing near the Fermi level due to Bi doping in the SnSe samples.Our results suggest the potentials of the Bi-doped SnSe thin films in thermoelectric applications.展开更多
Silica glasses doped with Bi2S3 microcystallite was prepared by the sol-gel process. Photoinduced second harmonic generation (SHG) was observed in the glass when it was irradiated with intense 1.06 μm and frequency d...Silica glasses doped with Bi2S3 microcystallite was prepared by the sol-gel process. Photoinduced second harmonic generation (SHG) was observed in the glass when it was irradiated with intense 1.06 μm and frequency doubled laser beams from a mode-locked Nd: YAG laser. It was found that the signal intensity increased with the irradiating time and approached a saturation gradually. The effect may be explained reasonably by the DC field model.展开更多
A series of Bi^(3+)-doped YAG:Ce^(3+), Mn^(2+) ceramics was synthesized successfully by gel-casting method and structurally characterized by XRD and SEM. The doping effect and related mechanism of Bi^(3+) upon the lum...A series of Bi^(3+)-doped YAG:Ce^(3+), Mn^(2+) ceramics was synthesized successfully by gel-casting method and structurally characterized by XRD and SEM. The doping effect and related mechanism of Bi^(3+) upon the luminescent property were studied. It can be assigned to the energy transfer of multipolar interaction from Bi^(3+) to Ce^(3+), leading to the improvement of emission intensity about 58% for 0.0001 Bi^(3+) and 0.05 Mn^(2+) doping. In addition, the emission is significantly red-shifted with the peak at 590 nm for the Y2.9939 Ce0.006 Bi0.0001 Al4.96 Mn0.02 Si0.02 O12 ceramic specimen with in-line transmittance 81.6% at 1100 nm. The LED module assembled from Y2.9939 Ce0.006 Bi0.0001 Al4.96 Mn0.02 Si0.02 O12 ceramic owns correlated color temperature(CCT) of 3960 K and luminous efficiency(LE) of 92 lm/W, implying that doping Bi^(3+) shows a good sensitization effect in the YAG:Ce^(3+), Mn^(2+) ceramic system and further serving as an attracting phosphor candidates for warm WLEDs applications.展开更多
The increase in occurrence and severity of cyanobacteria blooms is causing increasing concern;moreover,human and animal health is affected by the toxic effects of Microcystin-LR released into the water.In this paper,a...The increase in occurrence and severity of cyanobacteria blooms is causing increasing concern;moreover,human and animal health is affected by the toxic effects of Microcystin-LR released into the water.In this paper,a floating photocatalyst for the photocatalytic inactivation of the harmful algae Microcystis aeruginosa(M.aeruginosa)was prepared using a simple sol-gel method,i.e.,coating g-C_(3)N_(4) coupled with Bi-doped TiO_(2) on Al_(2)O_(3)-modified expanded perlite(CBTA for short).The impact of different molar ratios of Bi/Ti on CBTA was considered.The results indicated that Bi doping in TiO_(2) inhibited photogenerated electron-hole pair recombination.With 6 h of visible light illumination,75.9%of M.aeruginosa(initial concentration=2.7106 cells/L)and 83.7%of Microcystin-LR(initial concentration=100μg/L)could be removed with the addition of 2 g/L CBTA1%(i.e.,Bi/Ti molar ratio=1%).The key reactive oxygen species(ROSs)in the photocatalytic inactivation process are h+andOH.The induction of the Bi^(4+)/Bi^(3+)species by the incorporation of Bi could narrow the bandgap of TiO_(2),trap electrons,and enhance the stability of CBTA-1%in the solutions with coexisting environmental substances.展开更多
Bi doped SrTiO3 ceramics with Sr deficiency,i.e.Sr1-1.5xBixTiO3(x=0,0.01,0.05,0.1),were prepared via conventional solid-state reaction route.A colossal permittivity(CP)over 104 with low dielectric loss less than 0.05w...Bi doped SrTiO3 ceramics with Sr deficiency,i.e.Sr1-1.5xBixTiO3(x=0,0.01,0.05,0.1),were prepared via conventional solid-state reaction route.A colossal permittivity(CP)over 104 with low dielectric loss less than 0.05wasobtained in x=0.05 Sr1-1.5xBixTiO3 ceramics.In addition,the dielectric constant is maintained at a value greater than 104 in the range of 102-105 Hz and almost frequency independent.Phase structure analysis and density functional theory calculations suggest that the Bi·Sr-V"Sr-Bi·Sr defect complex with hole-pinned defect-dipoles maybe responsible for the high-performance CP properties.This work gives a new way to achieve high performance CP materials in ABO3 perovskite ceramics.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB0405702)the National Natural Science Foundation of China(Grant No.51672179).
文摘Bi doped n-type SnSe thin films were prepared by chemical vapor deposition(CVD)and their structure and thermoelectric properties were studied.The x-ray diffraction patterns,x-ray photoelectron spectroscopy,and microscopic images show that the prepared SnSe thin films were composed of pure SnSe crystals.The Seebeck coefficients of the Bi-doped SnSe were greatly improved compared to that of undoped SnSe thin films.Specifically,Sn_(0.99)Bi_(0.01)Se thin film exhibited a Seebeck coefficient of905.8μV·K^(-1) at 600 K,much higher than 285.5μV·K^(-1) of undoped SnSe thin film.Further first-principles calculations reveal that the enhancement of the thermoelectric properties can be explained mainly by the Fermi level lifting and the carrier pockets increasing near the Fermi level due to Bi doping in the SnSe samples.Our results suggest the potentials of the Bi-doped SnSe thin films in thermoelectric applications.
文摘Silica glasses doped with Bi2S3 microcystallite was prepared by the sol-gel process. Photoinduced second harmonic generation (SHG) was observed in the glass when it was irradiated with intense 1.06 μm and frequency doubled laser beams from a mode-locked Nd: YAG laser. It was found that the signal intensity increased with the irradiating time and approached a saturation gradually. The effect may be explained reasonably by the DC field model.
基金supported by the grants of CAS Priority Research program(XDB20010300,XDA21010204)Natural Science Foundation of Fujian Province(2017H0048)。
文摘A series of Bi^(3+)-doped YAG:Ce^(3+), Mn^(2+) ceramics was synthesized successfully by gel-casting method and structurally characterized by XRD and SEM. The doping effect and related mechanism of Bi^(3+) upon the luminescent property were studied. It can be assigned to the energy transfer of multipolar interaction from Bi^(3+) to Ce^(3+), leading to the improvement of emission intensity about 58% for 0.0001 Bi^(3+) and 0.05 Mn^(2+) doping. In addition, the emission is significantly red-shifted with the peak at 590 nm for the Y2.9939 Ce0.006 Bi0.0001 Al4.96 Mn0.02 Si0.02 O12 ceramic specimen with in-line transmittance 81.6% at 1100 nm. The LED module assembled from Y2.9939 Ce0.006 Bi0.0001 Al4.96 Mn0.02 Si0.02 O12 ceramic owns correlated color temperature(CCT) of 3960 K and luminous efficiency(LE) of 92 lm/W, implying that doping Bi^(3+) shows a good sensitization effect in the YAG:Ce^(3+), Mn^(2+) ceramic system and further serving as an attracting phosphor candidates for warm WLEDs applications.
基金the support of this research by the National Natural Science Foundation of China(Grant Nos.22008057 and 51909165)financially supported by the PhD.Scientific Research Starting Foundation of Henan Normal University(No.5101219170135)ostdoctoral Research Foundation of Henan Normal University(No.5101219470222).
文摘The increase in occurrence and severity of cyanobacteria blooms is causing increasing concern;moreover,human and animal health is affected by the toxic effects of Microcystin-LR released into the water.In this paper,a floating photocatalyst for the photocatalytic inactivation of the harmful algae Microcystis aeruginosa(M.aeruginosa)was prepared using a simple sol-gel method,i.e.,coating g-C_(3)N_(4) coupled with Bi-doped TiO_(2) on Al_(2)O_(3)-modified expanded perlite(CBTA for short).The impact of different molar ratios of Bi/Ti on CBTA was considered.The results indicated that Bi doping in TiO_(2) inhibited photogenerated electron-hole pair recombination.With 6 h of visible light illumination,75.9%of M.aeruginosa(initial concentration=2.7106 cells/L)and 83.7%of Microcystin-LR(initial concentration=100μg/L)could be removed with the addition of 2 g/L CBTA1%(i.e.,Bi/Ti molar ratio=1%).The key reactive oxygen species(ROSs)in the photocatalytic inactivation process are h+andOH.The induction of the Bi^(4+)/Bi^(3+)species by the incorporation of Bi could narrow the bandgap of TiO_(2),trap electrons,and enhance the stability of CBTA-1%in the solutions with coexisting environmental substances.
基金This work was supported by the National Natural Science Foundation of China[Grant Nos.51677033,51802061,51702069].
文摘Bi doped SrTiO3 ceramics with Sr deficiency,i.e.Sr1-1.5xBixTiO3(x=0,0.01,0.05,0.1),were prepared via conventional solid-state reaction route.A colossal permittivity(CP)over 104 with low dielectric loss less than 0.05wasobtained in x=0.05 Sr1-1.5xBixTiO3 ceramics.In addition,the dielectric constant is maintained at a value greater than 104 in the range of 102-105 Hz and almost frequency independent.Phase structure analysis and density functional theory calculations suggest that the Bi·Sr-V"Sr-Bi·Sr defect complex with hole-pinned defect-dipoles maybe responsible for the high-performance CP properties.This work gives a new way to achieve high performance CP materials in ABO3 perovskite ceramics.
