High-quality II-VI semiconductor ZnSe nanowires were facilely prepared in the oleic acid and oleylamine mixed solution at low temperatures of 130°C-200°C through an Ag2Se-catalyzed growth mechanism. Oleylami...High-quality II-VI semiconductor ZnSe nanowires were facilely prepared in the oleic acid and oleylamine mixed solution at low temperatures of 130°C-200°C through an Ag2Se-catalyzed growth mechanism. Oleylamine served as an effective reducing agent and a surfactant in the synthesis. Many of the resultant nanowires were terminated by an Ag2Se catalyst particle at one of their ends, confirming that the nanowire growth followed a catalytic mechanism. The crystal structure of Ag2Se catalyst was examined, which exhibited a metastable tetragonal phase, not the common orthorhombic phase. Meanwhile, the optical properties of as-synthesized ZnSe nanowire solid powder were evaluated by the UV-Visible diffuse reflectance and photoluminescence spectroscopy and a significant blue shift was observed compared to the bulk ZnSe with a band gap of 2.7 eV. This work would provide an alternative and effective catalytic route for the preparation of one-dimensional (1D) nanostructures of ZnSe and other metal selenides.展开更多
Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass pl...Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450℃. Then,the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal,and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs,the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light,which have been confirmed by the photoelectrochemical measurements.展开更多
The coupling of charge carrier and phonon transport limits the application of Ag_(2)Se as a low-toxic near-room-temperature thermoelectric material.Strategies that reduce the thermal conductivity via enhanc-ing the ph...The coupling of charge carrier and phonon transport limits the application of Ag_(2)Se as a low-toxic near-room-temperature thermoelectric material.Strategies that reduce the thermal conductivity via enhanc-ing the phonon scattering usually lead to reduced carrier mobility due to high grain boundary potential barrier.In this study,we developed a cell-membrane-mimic grain boundary engineering strategy for de-coupling the charge carrier and phonon scattering through decorating high-dielectric-constant rutile TiO_(2) at Ag_(2)Se grain boundaries to enable the charge carrier/phonon selective permeability.The nano-sized TiO_(2) with high dielectric permittivity can secure the charge carrier transport by shielding the interfacial Coulomb potential to lower the energy barrier of grain boundaries,rendering an enhanced power factor.Additionally,benefited from the enhanced phonon scattering by TiO_(2) nanoparticles,a significantly de-creased lattice thermal conductivity of~0.20 W m^(-1) K^(-1) and a high zT of~0.97 at 390 K are obtained in the Ag_(2)Se-based nanocomposites.This work demonstrates that such cell-membrane-mimic grain bound-ary engineering strategy may shed light on developing high-performance thermoelectric materials.展开更多
In this work,Ag/Ag_(2)Se composite films with excellent thermoelectric(TE)properties and flexibility are prepared based on a simple one-pot method.By adjusting the nominal ratios of Ag/Se,an optimal Ag/Ag_(2)Se compos...In this work,Ag/Ag_(2)Se composite films with excellent thermoelectric(TE)properties and flexibility are prepared based on a simple one-pot method.By adjusting the nominal ratios of Ag/Se,an optimal Ag/Ag_(2)Se composite film shows a large power factor of~2275 μW m^(-1) K^(-2) at 300 K.Such an outstand-ing TE performance of the composite film is due to the unique microstructure and the synergistic effect between the Ag and Ag_(2)Se.Meanwhile,the composite film also shows outstanding flexibility(~91.8%of the initial electrical conductivity is maintained,and the S is unchanged after 1500 bending cycles with a bending radius of 4 mm).Furthermore,a 4-leg flexible TE generator assembled with the optimal film produces a voltage of 14.06 mV and 4.96 μW at a temperature difference of 30.4 K.This work provides a new inspiration for the preparation of flexible Ag_(2)Se-based films with excellent TE performance near room temperature.展开更多
文摘High-quality II-VI semiconductor ZnSe nanowires were facilely prepared in the oleic acid and oleylamine mixed solution at low temperatures of 130°C-200°C through an Ag2Se-catalyzed growth mechanism. Oleylamine served as an effective reducing agent and a surfactant in the synthesis. Many of the resultant nanowires were terminated by an Ag2Se catalyst particle at one of their ends, confirming that the nanowire growth followed a catalytic mechanism. The crystal structure of Ag2Se catalyst was examined, which exhibited a metastable tetragonal phase, not the common orthorhombic phase. Meanwhile, the optical properties of as-synthesized ZnSe nanowire solid powder were evaluated by the UV-Visible diffuse reflectance and photoluminescence spectroscopy and a significant blue shift was observed compared to the bulk ZnSe with a band gap of 2.7 eV. This work would provide an alternative and effective catalytic route for the preparation of one-dimensional (1D) nanostructures of ZnSe and other metal selenides.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20875001, 20775001, 50532030 & 20771001)Innovation Foundation of Anhui Province (Grant No. 2006KJ007TD)
文摘Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450℃. Then,the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal,and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs,the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light,which have been confirmed by the photoelectrochemical measurements.
基金National Natural Science Foundation of China(Nos.12074015,52002254,52272160)Sichuan Science and Technology Program(No.2023YFG0220)+3 种基金Fundamental Research Funds for the Central Universities(No.YJ202242)Research Funding from West China School/Hospital of Stomatology Sichuan University,(No.QDJF2022-2)State Key Laboratory for Mechanical Behavior of Materials(No.20232509)fund of the State Key Laboratory of Solidifica-tion Processing in NPU(No.SKLSP202315).
文摘The coupling of charge carrier and phonon transport limits the application of Ag_(2)Se as a low-toxic near-room-temperature thermoelectric material.Strategies that reduce the thermal conductivity via enhanc-ing the phonon scattering usually lead to reduced carrier mobility due to high grain boundary potential barrier.In this study,we developed a cell-membrane-mimic grain boundary engineering strategy for de-coupling the charge carrier and phonon scattering through decorating high-dielectric-constant rutile TiO_(2) at Ag_(2)Se grain boundaries to enable the charge carrier/phonon selective permeability.The nano-sized TiO_(2) with high dielectric permittivity can secure the charge carrier transport by shielding the interfacial Coulomb potential to lower the energy barrier of grain boundaries,rendering an enhanced power factor.Additionally,benefited from the enhanced phonon scattering by TiO_(2) nanoparticles,a significantly de-creased lattice thermal conductivity of~0.20 W m^(-1) K^(-1) and a high zT of~0.97 at 390 K are obtained in the Ag_(2)Se-based nanocomposites.This work demonstrates that such cell-membrane-mimic grain bound-ary engineering strategy may shed light on developing high-performance thermoelectric materials.
基金National Natural Science Foundation of China (Nos. 92163118 and 51972234).
文摘In this work,Ag/Ag_(2)Se composite films with excellent thermoelectric(TE)properties and flexibility are prepared based on a simple one-pot method.By adjusting the nominal ratios of Ag/Se,an optimal Ag/Ag_(2)Se composite film shows a large power factor of~2275 μW m^(-1) K^(-2) at 300 K.Such an outstand-ing TE performance of the composite film is due to the unique microstructure and the synergistic effect between the Ag and Ag_(2)Se.Meanwhile,the composite film also shows outstanding flexibility(~91.8%of the initial electrical conductivity is maintained,and the S is unchanged after 1500 bending cycles with a bending radius of 4 mm).Furthermore,a 4-leg flexible TE generator assembled with the optimal film produces a voltage of 14.06 mV and 4.96 μW at a temperature difference of 30.4 K.This work provides a new inspiration for the preparation of flexible Ag_(2)Se-based films with excellent TE performance near room temperature.
