0428同步年報-2021-全

064 ACTIVITY REPORT 2021 confirms the feasibility and great prospects of NASICON- type LZPO coatings for sulfide-based HVASSLB. In summary, NASICON-type LZPO with high oxidation limits and reasonable ionic conductivity was demonstrated as a proof of concept for a bidirectionally compatible buffering- layer design scheme to overcome the interfacial challenges of sulfide-based HVASSLB. 4.5-V LZPO-LCO/LPSCl/In-Li HVASSLBs could thereby exhibit an initial discharge capacity up to 143.3 mA h g −1 at 0.2 C, and excellent long- cycle performance (95.53% capacity retention after 100 cycles). This work sheds light on the great prospects of sulfide-based HVASSLB with high-rate characteristics, and constitutes a crucial step toward the rational design of the interface and interphase chemistry for high-performance sulfide-based HVASSLB. (Reported by Yan-Gu Lin) This report features the work of Guanglei Cui and his collaborators published in Adv. Energy Mater. 11 , 2100881 (2021). TLS 16A1 Tender X-ray Absorption, Diffraction • XANES, EXAFS • Materials Science, Chemistry, Condensed-matter Physics, Environmental and Earth Science Reference 1. L. Wang, X. Sun, J. Ma, B. Chen, C. Li, J. Li, L. Chang, X. Yu, T.-S. Chan, Z. Hu, M. Noked, G. Cui, Adv. Energy Mater. 11 , 2100881 (2021). Catching Hidden Structural Evolution in Near- Infrared Phosphors The random distribution of Ga 3+ and Sc 3+ ions at the Ga2 site of Ga 2 O 3 greatly affects the photoluminescent properties. R ecently, phosphor-converted IR light-emitting diodes (pc-IR LEDs) have evolved into smart devices with the advantages of large output power, high efficiency and small size. IR phosphor materials are crucial components of these devices, affecting the overall performance of the resulting spectrum. Cr 3+ , as a unique and ideal near-IR emitter that can produce either sharp-line or broadband spectra, has become a promising candidate for producing IR light. Although substantial progress has been achieved in this popular topic, most studies have focused on a single compound or on changing activators without systematically tuning the crystal structure and the luminescent wavelength. Consequently, understanding the control mechanism is considered an important issue in tuning luminescent properties. Some local structural distortions or phase transitions might result in unexpected photoluminescent properties. Moreover, a subtle change in the local structure might tune photoluminescence between sharp-line or broadband emissions. This phenomenon has been seldom discussed in previous studies. The overall tuning mechanism remains vague. Ru-Shi Liu (National Taiwan University) and his coworkers recently conducted a complete study on the unexpected structure evolution behavior in Cr 3+ -doped phosphors. Ga 1.994− x Sc x O 3 :0.006Cr 3+ (Ga 2− x Sc x O 3 :Cr 3+ ) phosphors in a series were synthesized; their unique structural and photoluminescent properties were characterized, demonstrating their high potential in IR-LED applications. Employing X-ray diffraction (XRD) measurements at beamline TLS 01C2 , 1 the unique partial substitution (~87%) of Sc 3+ in the octahedral site was demonstrated via Rietveld refinement. The synchrotron XRD patterns of Ga 2− x Sc x O 3 :Cr 3+ phosphors with varied Sc 3+ concentration are shown in Fig. 1(a) . The pure phase was obtained at x = 0–0.8; Sc 2 O 3 impurities existed at x = 1 and 1.2. The diffraction signals shifted toward lower angle on incorporation of Sc 3+ ions because of the ionic size of Sc 3+ (0.745 Å; CN = 6) larger than that of Ga 3+ (0.47 Å; CN = 6) (CN denotes coordination number). Unexpectedly, the diffraction peaks did not shift linearly for x > 0.8. This finding might indicate the failure of the Sc 3+ doping when x > 0.8. To investigate this unique behavior in-depth, Rietveld refinements of Ga 2− x Sc x O 3 :Cr 3+ were conducted and analyzed. The lattice parameters, namely, a , b , c , and V , linearly increased for x = 0–0.8, as shown in Fig. 1(b) . The speed of ascent decreased from x = 0.8–1.0 and even stopped increasing from x = 1.0–1.2. To understand this property, the crystal structure and local coordinated environment of Ga 2 O 3 were also carefully examined. Ga 2 O 3 possesses a monoclinic structure with space group C2/m. Two distinct Ga 3+ sites, namely, Ga1 and Ga2, were found in the Ga 2 O 3 structure. Ga2 is coordinated with six O 2– forming an octahedron; Ga1 is coordinated by four O 2– forming a tetrahedron. When introducing Sc 3+ into