Photon upconversion based on sensitized triplet-triplet annihilation (sTTA) is considered as a promising strategy for the development of light-managing materials aimed to enhance the performance of solar devices by recovering unused low-energy photons. Here, we demonstrate that, thanks to the fast diffusion of excitons, the creation of triplet pairs in metal-organic framework nanocrystals (nMOFs) with size smaller than the exciton diffusion length implies a 100% TTA yield regardless of the illumination condition. This makes each nMOF a thresholdless, single-unit annihilator. We develop a kinetic model for describing the upconversion dynamics in a nanocrystals ensemble, which allows us to define the threshold excitation intensity Ith box required to reach the maximum conversion yield. For materials based on thresholdless annihilators, Ith box is determined by the statistical distribution of the excitation energy among nanocrystals. The model is validated by fabricating a nanocomposite material based on nMOFs, which shows efficient upconversion under a few percent of solar irradiance, matching the requirements of real life solar technologies. The statistical analysis reproduces the experimental findings, and represents a general tool for predicting the optimal compromise between dimensions and concentration of nMOFs with a given crystalline structure that minimizes the irradiance at which the system starts to fully operate.

Meinardi, F., Ballabio, M., Yanai, N., Kimizuka, N., Bianchi, A., Mauri, M., et al. (2019). Quasi-thresholdless Photon Upconversion in Metal-Organic Framework Nanocrystals. NANO LETTERS, 19(3), 2169-2177 [10.1021/acs.nanolett.9b00543].

Quasi-thresholdless Photon Upconversion in Metal-Organic Framework Nanocrystals

Meinardi, F.;Mauri, M.
Membro del Collaboration Group
;
Simonutti, R.;Ronchi, A.
Membro del Collaboration Group
;
Campione, M.;Monguzzi, A.
2019

Abstract

Photon upconversion based on sensitized triplet-triplet annihilation (sTTA) is considered as a promising strategy for the development of light-managing materials aimed to enhance the performance of solar devices by recovering unused low-energy photons. Here, we demonstrate that, thanks to the fast diffusion of excitons, the creation of triplet pairs in metal-organic framework nanocrystals (nMOFs) with size smaller than the exciton diffusion length implies a 100% TTA yield regardless of the illumination condition. This makes each nMOF a thresholdless, single-unit annihilator. We develop a kinetic model for describing the upconversion dynamics in a nanocrystals ensemble, which allows us to define the threshold excitation intensity Ith box required to reach the maximum conversion yield. For materials based on thresholdless annihilators, Ith box is determined by the statistical distribution of the excitation energy among nanocrystals. The model is validated by fabricating a nanocomposite material based on nMOFs, which shows efficient upconversion under a few percent of solar irradiance, matching the requirements of real life solar technologies. The statistical analysis reproduces the experimental findings, and represents a general tool for predicting the optimal compromise between dimensions and concentration of nMOFs with a given crystalline structure that minimizes the irradiance at which the system starts to fully operate.
Articolo in rivista - Articolo scientifico
metal-organic frameworks; nanocomposite; nanocrystals; Photon upconversion; triplet-triplet annihilation; Bioengineering; Chemistry (all); Materials Science (all); Condensed Matter Physics; Mechanical Engineering
English
2019
19
3
2169
2177
partially_open
Meinardi, F., Ballabio, M., Yanai, N., Kimizuka, N., Bianchi, A., Mauri, M., et al. (2019). Quasi-thresholdless Photon Upconversion in Metal-Organic Framework Nanocrystals. NANO LETTERS, 19(3), 2169-2177 [10.1021/acs.nanolett.9b00543].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/240432
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