Triplet properties and intersystem crossing mechanism of PtAg28 nanocluster sensitizers achieving low threshold and efficient photon upconversion

The combination of the PtAg28 nanocluster sensitizer with a 9,10-diphenylanthracene emitter achieved a low upconversion threshold of 0.8 mW cm −2 at 532 nm excitation, along with efficient upconversion under 1-sun conditions.