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Efficient energy transfer from sensitizer to activator in phosphors is very important for white LEDs. Bi 3+ and Eu 3+ co-doped red phosphor is a potential alternative for white LEDs. However, energy transfer from Bi 3+ to Eu 3+ ions is still not efficient enough in most cases. Here we have found that every six Zn sites forming an S-shaped cluster in ZnMoO4 crystal. Two Zn(2) sites will be occupied preferentially in ZnMoO4 according to the comparison between calculated and experimental A band positions of Bi 3+ in ZnMoO4 host. Considering the S-shaped cluster and site occupation preference, a super energy transfer process from Bi 3+ to Eu 3+ ions is proposed. The distance between Bi 3+ and Eu 3+ ions can be controlled by their total doping concentrations. When their total molar concentration is beyond 1/6, Bi 3+ and Eu 3+ began to sit two adjacent Zn(2) sites. Thus, the new super energy transfer from Bi 3+ to Eu 3+ emerged due to adjacent Bi 3+ and Eu 3+ ions. When excited at 331 or 350 nm, which is assigned to 1 S0→ 3 P1 transition of Bi 3+ , the phosphor emits intense red light. The relative intensity is about 6 times higher than that with ordinary transfer process. It gives a good example to utilize the site occupation preference and provides a new way to design efficient phosphors. Therefore, we believe that the concentrate quenching occurred due to the same reason in ZnMoO 4 :Tb 3+ .In ZnMoO 4 phosphor, Bi 3+ and Eu 3+ ions were trapped together in the S-shaped cluster. The super energy transfer process from Bi 3+ to Eu 3+ occurred due to their short distance.

Local drug injection therapy for tumor site, as a neoadjuvant chemotherapy method, shows important significance in clinical application; however, it obtains unsatisfying therapeutic effect due to the serious toxic and side effect in normal tissues caused by drug diffusion or complexity of the preparation. In this article, the influence factors of the gelling time of traditional Chitosan (CTS) thermo-sensitive hydrogels were analyzed, and the gelling properties were improved significantly, and a thermosensitive hydrogel with precisely regulated gelling time was obtained through a green and simple preparation method, and the shortest gelling time (gelling time = 27 ± 2 s) of this hydrogel was 5% of that of the common CTS thermo-sensitive hydrogels. After loaded with different chemotherapy drugs with different pH values (gemctiabin hydrochloride, levofloxacin, and 5-foluorouracil), the hydrogels' gelling performance was not affected, while the gelling time could be shortened by 5-foluorouracil, effectively hindering the drug loss at the early stage of sustained release. in vitro and in vivo experiments proved that precise encapsulation toward tumors with different volumes was achieved by the hydrogels, with minimal damage to surrounding normal tissues and higher utilization of drugs in tumor sites, ultimately achieving better tumor therapeutic effect. In conclusion, the new thermo-sensitive hydrogels with precisely regulated gelling time showed great significance and potential for drug delivery and neoadjuvant chemotherapy. K E Y W O R D S drug-controlled release, gelling time, neoadjuvant chemotherapy, therapy in situ, thermosensitive hydrogels 1 | INTRODUCTION Thermo-sensitive hydrogels could achieve transformation between liquid and hydrogels according to the actual environmental temperature and act as a drug reservoir in injection site, with the advantages of controlled release, targeted drug delivery, and low toxicity (Culver,