Efficient Visible‐to‐UV Photon Upconversion Systems Based on CdS Nanocrystals Modified with Triplet Energy Mediators
Artikel i vetenskaplig tidskrift, 2021

Developing high-performance visible-to-UV photon upconversion systems based on triplet–triplet annihilation photon upconversion (TTA-UC) is highly desired, as it provides a potential approach for UV light-induced photosynthesis and photocatalysis. However, the quantum yield and spectral range of visible-to-UV TTA-UC based on nanocrystals (NCs) are still far from satisfactory. Here, three different sized CdS NCs are systematically investigated with triplet energy transfer to four mediators and four annihilators, thus substantially expanding the available materials for visible-to-UV TTA-UC. By improving the quality of CdS NCs, introducing the mediator via a direct mixing fashion, and matching the energy levels, a high TTA-UC quantum yield of 10.4% (out of a 50% maximum) is achieved in one case, which represents a record performance in TTA-UC based on NCs without doping. In another case, TTA-UC photons approaching 4 eV are observed, which is on par with the highest energies observed in optimized organic systems. Importantly, the in-depth investigation reveals that the direct mixing approach to introduce the mediator is a key factor that leads to close to unity efficiencies of triplet energy transfer, which ultimately governs the performance of NC-based TTA-UC systems. These findings provide guidelines for the design of high-performance TTA-UC systems toward solar energy harvesting.

photon upconversion

triplet energy transfer

semiconductor nanocrystals

triplet–triplet annihilation

CdS nanocrystals


Lili Hou

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Axel Olesund

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Shameel Thurakkal

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Xiaoyan Zhang

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Bo Albinsson

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Advanced Functional Materials

1616-301X (ISSN) 16163028 (eISSN)

Vol. 31 47 2106198

Uppkonvertering av fotonenergier i fastfas: Nya material för att bryta Shockley-Queisser gränsen

Energimyndigheten (46526-1), 2019-01-01 -- 2023-12-31.

Okonventionell solelsteknologi

Energimyndigheten (36436-2), 2017-01-17 -- 2020-12-31.


Oorganisk kemi

Annan fysik

Kompositmaterial och -teknik



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