- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Zn <sub/>3</sub> Ga <sub/>2</sub> Ge <sub/>2</sub> O <sub/>10</sub> :Cr <sup>3+</sup> Uniform Microspheres: Template-Free Synthesis, Tunable Bandgap/Trap Depth, and <i>In Vivo</i> Rechargeable Near-Infrared-Persistent Luminescence
摘要： Near-infrared (NIR) emitting persistent phosphors of Cr3+-doped zinc gallogermanate have emerged for in vivo bio-imaging with the advantages of no need for in situ excitation. However, it is challenging to synthesize well-dispersed and uniform spherical particles with high brightness, high resolution, and distinguished NIR long afterglow. In this work, Zn3Ga2Ge2O10:Cr3+ (ZGGC) monospheres were directly synthesized by a facile hydrothermal method with the assistance of citric anions (Cit3-), which emit a NIR emission at ~696 nm and exhibit excellent NIR persistent luminescence with rechargeability. Controlled experiments indicated that the shape evolution of ZGGC product is significantly affected by Cit3-, solution pH, and the duration and temperature of hydrothermal reaction. Furthermore, compositional influence on the crystal structure, bandgap, trap depth, and luminescence characteristics of ZnyGa2Ge2O10-δ:Cr3+ (y = 2.8, 3.0, 3.2) were investigated in details, which allows to construct an energy level diagram of the ZGGC host, Cr3+ ions, and electron traps. It was found that the bandgap and conduction-band minimum (CBM) are significantly affected by the Zn content, while the valence-band maximum (VBM) is not. The y = 3.0 sample exhibited the best persistent luminescence, owing to its deepest defects. The ZGGC-NH2 prepared through surface functionalization of ZGGC spheres showed distinguished NIR long afterglow, low toxicity, and great potential for in vitro cell imaging and in vivo bio-imaging in the absence of excitation. Moreover, the persistent-luminescence signal from the ZGGC-NH2 can be repeated in vivo through in situ recharge with external excitation of a red LED lamp, indicating that the ZGGC-NH2 is suitable for applications in long-term in vivo imaging.
关键词： in vivo imaging,Near infrared persistent luminescence,conduction band minimum,monospheres
更新于2025-09-23 15:23:52
-
Application of Al-Doped (Zn, Mg)O on pure-sulfide Cu(In, Ga)S2 solar cells for enhancement of open-circuit voltage
摘要： In this study, interfacial recombination observed by activation energy (Ea) is reduced with an improvement in the built-in potential (Vbi) by raising the conduction band minimum (EC) in Al-doped (Zn, Mg)O (AZMO) layer for pure-sul?de Cu(In, Ga)S2 (CIGS) solar cells. It is observed that the optical band gap in AZMO ?lms can be widened from 3.56 to 3.97 eV with increasing Mg/(Mg + Zn) ratio from 0 to 0.23, suggesting the shift of EC toward the vacuum level. AZMO layers with Mg/(Mg + Zn) ratio of 0–0.23 are applied as transparent conductive oxide (TCO) for the pure-sul?de CIGS solar cells. The open-circuit voltage is clearly enhanced from 0.641 to 0.713 V with increasing Mg/(Mg + Zn) ratio from 0 to 0.09 and then decreased to 0.651 V at Mg/(Mg + Zn) ratio of 0.23 in the AZMO layer. Reverse saturation current density (J0) was minimized to 9.4 × 10?7 A/cm2 at Mg/(Mg + Zn) of 0.09, although J0 was 4.7 × 10?6 A/cm2 in Al-doped ZnO (Mg/(Mg + Zn) of 0). From Mott-Schottky plot, it is observed that Vbi for the pure-sul?de CIGS solar cells gradually enhanced with an increase in Mg/(Mg + Zn) from 0 to 0.23 in the AZMO layer. These results suggest that Vbi improves by controlling EC in the TCO layer, which ultimately reduces the recombination at the hetero interface owing to strengthened electric ?eld.
关键词： Al-doped (Zn, Mg)O,Chalcopyrite,Thin-?lm solar cell,Built-in potential,Conduction band minimum,Cu(In, Ga)S2
更新于2025-09-16 10:30:52
-
Optical properties and electronic structures of Cu <sub/>2</sub> ZnSnS <sub/>4</sub> , Cu <sub/>2</sub> ZnGeS <sub/>4</sub> , and Cu <sub/>2</sub> Zn(Ge,Sn)S <sub/>4</sub> and Cu <sub/>2</sub> Zn(Ge,Sn)Se <sub/>4</sub> solid solutions
摘要： Cu2Zn(GexSn1%x)S4 (CZGTS) samples were synthesized by a mechanochemical process and sequential heating. The phases in the obtained powders were analyzed by X-ray di?raction. The band-gap energies of the CZGTS samples were determined by the di?use re?ectance spectra of UV–vis–NIR spectroscopy. The band gap energy of the CZGTS system linearly increased from 1.49 eV for Cu2ZnSnS4 (x = 0.0) to 2.25 eV for Cu2ZnGeS4 (x = 1.0). Their energy levels of valence band maximum (VBM) from the vacuum level were estimated from the ionization energies measured by photoemission yield spectroscopy (PYS). The energy levels of conduction band minimum (CBM) were determined by addition of the band-gap energies to the VBM levels. The energy level of VBM of the CZGTS solid solution was almost constant. On the other hand, the CBM level of the CZGTS solid solution linearly increased from %3.96 eV for Cu2ZnSnS4 (x = 0.0) to %3.28 eV for Cu2ZnGeS4 (x = 1.0) with the increasing Ge content. For CZGTS solar cells with CdS bu?er layer, unfavorable cli?-type conduction band o?set was expected. We also synthesized Cu2ZnSnSe4, Cu2ZnGeSe4, and Cu2Zn(Ge,Sn)Se4 (CZGTSe) solid solution samples and determined their energy levels of VBM and CBM. For Cu2Zn(GexSn1%x)Se4 system with 0.3 3 x 3 1.0, similar cli?-type conduction band o?set was is expected. However, desirable positive spike-type conduction band o?set was expected for the Cu2Zn(GexSn1%x)Se4 solar cells with 0.0 3 x 3 0.2 and CdS bu?er layer.
关键词： photoemission yield spectroscopy,Cu2Zn(GexSn1%x)S4,conduction band minimum,valence band maximum,band-gap energies,solar cells
更新于2025-09-09 09:28:46