To break through the bottle-neck of quantum yield in upconversion （UC） core-shell system, we elucidated that the energy transfer efficiency in core-shell system had an evident contribution from the charge transfer o...To break through the bottle-neck of quantum yield in upconversion （UC） core-shell system, we elucidated that the energy transfer efficiency in core-shell system had an evident contribution from the charge transfer of interface with related to two factors： （i） band offsets and （2） binding energy area density. These two variables were determined by material intrinsic properties and core-shell thickness ratio. We further unraveled the mechanism of non-radiative energy transfer by charge transfer induced dipole at the inter- face, based on a quasi-classical derivation from F6rster type resonant energy transfer （FRET） model. With stable bonding across the interface, the contributions on energy transfer in both radiative and non-radiative energy transfer should also be accounted together in Auzel＇s energy transfer （ETU） model in core-shell system. Based on the discussion about interface bonding, band offsets, and forma- tion energies, we figured out the significance of interface bonding induced gap states （IBIGS） that played a significant role for influ- encing the charge transfer and radiative type energy transfer. The interface band offsets were a key factor in dominating the non-radiative energy transfer, which was also correlated to core-shell thickness ratio. We found that the energy area density with re- lated to core/shell thickness ratio followed the trend of Boltzman sigmoidal growth function. By the physical trend, this work contrib- uted a reference how the multi-layered core-shell structure was formed starting from the very beginning within minimum size. A route was paved towards a systematic study of the interface to unveil the energy transfer mechanism in core-shell systems.展开更多
基金Project supported by the National Natural Science Foundation of China(NSFC)(21425101,21321001,21371011,21331001)Ministry of Science and Technology(MOST)of China(2014CB643800)+3 种基金Natural Science Foundation of China(NSFC) for the Youth Scientist grant(11504309)the Initial Start-up Grant Support from the Department General Research Fund(Dept.GRF) from ABCT in the Hong Kong Polytechnic Universitythe Early Career Scheme(ECS) Fund(PolyU 253026/16P) from the Research Grant Council(RGC)in Hong Kongthe High Performance Supercomputer(ATOM Project)in PolyU
文摘To break through the bottle-neck of quantum yield in upconversion （UC） core-shell system, we elucidated that the energy transfer efficiency in core-shell system had an evident contribution from the charge transfer of interface with related to two factors： （i） band offsets and （2） binding energy area density. These two variables were determined by material intrinsic properties and core-shell thickness ratio. We further unraveled the mechanism of non-radiative energy transfer by charge transfer induced dipole at the inter- face, based on a quasi-classical derivation from F6rster type resonant energy transfer （FRET） model. With stable bonding across the interface, the contributions on energy transfer in both radiative and non-radiative energy transfer should also be accounted together in Auzel＇s energy transfer （ETU） model in core-shell system. Based on the discussion about interface bonding, band offsets, and forma- tion energies, we figured out the significance of interface bonding induced gap states （IBIGS） that played a significant role for influ- encing the charge transfer and radiative type energy transfer. The interface band offsets were a key factor in dominating the non-radiative energy transfer, which was also correlated to core-shell thickness ratio. We found that the energy area density with re- lated to core/shell thickness ratio followed the trend of Boltzman sigmoidal growth function. By the physical trend, this work contrib- uted a reference how the multi-layered core-shell structure was formed starting from the very beginning within minimum size. A route was paved towards a systematic study of the interface to unveil the energy transfer mechanism in core-shell systems.
