Photon Upconversion through a Cascade Process of Two-Photon Absorption in CsPbBr₃ and Triplet–Triplet Annihilation in Porphyrin/Diphenylanthracene

Photon upconversion constitutes an exceptionally rich area of research in photonics and electronics, where low-energy light is converted to high-energy light through nonlinear processes represented by two-photon absorption (TPA) and triplet–triplet annihilation (TTA). Here, we report a cascade process of TPA in inorganic perovskite quantum dots (PQDs) of CsPbBr₃ and TTA in an organic molecule (9,10-diphenylanthracene) mediated by an octaethylporphyrinatoplatinum­(II) (PtOEP) sensitizer. This sequential energy transfer enables upconversion from four photons from a near-infrared femtosecond laser at 800 nm to one photon at 430 nm with a large anti-Stokes shift of ∼1.3 eV. We characterize the energy transfer from PQDs to PtOEP by picosecond lifetime spectroscopy and a Stern–Volmer plot of the steady-state photoluminescence while considering dynamic and static quenching as well as trivial absorption and Förster (fluorescence) resonance energy transfer. The serial connection of TPA and TTA achieved in a simple system opens up an attractive avenue in nonlinear photonics and harvesting of low-energy photons

Investigation of Asian Dyes and Pigments from the Artifact of “Murongzhi” and the Silk Road in China

In this paper, a series of modern analysis methods, including Raman spectroscopy, X-ray diffraction, UV–vis spectrophotometry, and ultra-high-pressure liquid chromatography coupled with a thermoelectric LTQ-Orbitrap XL ETD mass spectrometer (UHPLC-MS/MS), were applied to analyze and accurately identify the chemical composition of plant dyes and the mineral pigment from the samples collected from grave goods. As a result, the textiles were dyed by the madder, Kermes, Phellodendron chinense, indigo, Lithospermum L., and so forth. In addition, the mineral pigment, charcoal, hematite, minium, cinnabar, azurite, and malachite were used to paint the exquisite artifacts in the tomb of Murongzhi. This research demonstrates the profound impact on cultural transmission and fusion in the “Tuyuhong” dynasty and explores the Silk Road in Tang dynasty