Chiral dual-annihilator model for controllable photon upconversion and multi-dimensional optical modulation.

Triplet-triplet annihilation photon upconversion seeks efficient conversion of low-energy photons to high-energy emission. However, the triplet-triplet annihilation photon upconversion system faces limitations in emission gamut because efficient triplet-triplet energy transfer between sensitizer and annihilator relies on triplet energy matching, making it challenging to realize multi-channel luminescence and multi-dimensional optical control. Here, to overcome this barrier, we propose a chiral dual-annihilator model, which mitigates the restriction of energy matching and achieves facile manipulation of circularly polarized luminescence through a dual-channel triplet-triplet energy transfer process. A theoretical equation for quantifying the overall triplet-triplet energy transfer efficiency and the energy flow between the sensitizer and two kinds of annihilators is proposed. Its accuracy is demonstrated by fine-controlling the emission bandwidth of triplet-triplet annihilation photon upconversion (average error less than 4.5%) in the experimental aspect. In addition, by introducing chiral liquid crystals, the dual-annihilator model achieves data coding and multi-dimensional optical encryption applications. This dual-annihilator model deepens the understanding of energy flow and lays the foundation for accurate, multidimensional modulation of photon upconversion.