Light Scattering-enhanced Upconversion Efficiency in Silica Microparticles-embedded Polymeric Thin Film

고분자 박막 내에 담지 된 실리카 마이크로입자의 광산란 효과에 의한 광에너지 상향전환 효율 향상

Choe, Hyun-Seok;Lee, Hak-Lae;Lee, Myung-Soo;Park, Jeong-Min;Kim, Jae-Hyuk

  • Received : 2018.11.26
  • Accepted : 2018.12.09
  • Published : 2019.02.10


Triplet-triplet annihilation upconversion (TTA-UC) is a photochemical process wherein two or more low-energy photons are converted to a high-energy photon through a special energy transfer mechanism. Herein, we report a strategy to enhance the efficiency of TTA-UC through the light-scattering effect induced by silica microparticles (SM) embedded in polymeric thin films. By incorporating monodisperse uniform silica microparticles with a uniform size of 950 nm synthesized by $St{\ddot{o}}ber$-based seeded growth method into UC polymeric thin films, the UC intensity in the 430-570 nm range was enhanced by as much as 64% when irradiated by 635 nm laser. Analyzing the lifetime of PdTPBP phosphorescence revealed that the presence of SM in the UC layer does not affect triplet-triplet energy transfer (TTET) between sensitizers and acceptors, supporting the enhancement of TTA-UC originated from the light-scattering effect. On the other hand, the incorporation of SM in UC layer is shown to enhance the triplet-triplet annihilation (TTA) efficiency, which results in a 1.5-fold increase of the ${\Phi}_{UC}$, by scattering light source and thus increasing the number of excited photons to be utilized in TTA-UC process.


Silica microparticles;Seeded growth;Triplet-triplet annihilation;Upconversion;Polymeric thin film


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Supported by : 한국연구재단