The 70th JSAP Spring Meeting 2023

Presentation information

Oral presentation

1 Interdisciplinary Physics and Related Areas of Science and Technology » 1.4 Energy conversion, storage, resources and environment

[15a-D505-1~7] 1.4 Energy conversion, storage, resources and environment

Wed. Mar 15, 2023 9:30 AM - 11:15 AM D505 (Building No. 11)

Katsushi Fujii(RIKEN)

9:45 AM - 10:00 AM

[15a-D505-2] Near-infrared-to-visible photon upconversion in solid state using PbS QD sensitized triplet-triplet annihilation system by 980-nm excitation

Neeti Tripathi1, Masanori Ando2, Tomoko Akai1, Kenji Kamada1 (1.NMRI, AIST, 2.BMRI, AIST)

Keywords:Photon Upconversion, PbS quantum dots, Triplet-Triplet annihilation

Development of near infrared (NIR)-to-visible upconversion materials is extremely important for the efficient use of solar energy. Triplet-triplet annihilation photon upconversion (TTA-UC) may allow to achieve it under the excitation intensities as low as sunlight. Recently, quantum dot (QD) sensitized TTA-UC showed significant progress in this field, however, upconversion performance of QD-sensitized hybrid system is affected by various factors, i.e., capping ligand, defect states etc. Changing the physical state of the system from solution to solid also give significant impact.
We developed a solid-state TTA-UC system using PbS QD as sensitizer and (5,11-bis(triethylsilylethynyl)anthradi- thiophene, TES-ADT) as visible emitter, which successfully converts 980-nm photons into a 660-nm visible photon. A narrow bandgap PbS QD with emission wavelength 1100 nm, is suitable to absorb NIR photons and TES-ADT having ability to attach to QD, providing ~93% triplet energy transfer (TET) from QD to TES-ADT. With optimized concentrations and other experimental conditions, the best upconversion emission efficiency (UC-QE) (at 100% scale) of 0.68% under the 980 nm excitation. These solid UC films showed superior UC-QE, compared to than that of the solution system.