Photoinduced ligand-to-metal charge transfer(LMCT) has emerged as an effective strategy for synthesizing organic molecules in a sustainable manner. However, the majority of existing reports on selective C(sp^(3))–H b...Photoinduced ligand-to-metal charge transfer(LMCT) has emerged as an effective strategy for synthesizing organic molecules in a sustainable manner. However, the majority of existing reports on selective C(sp^(3))–H bond functionalization via photoinduced LMCT focus on the use of late transition metals or rare-earth metals for radical additions or cross-couplings. In contrast, the utilization of photoinduced LMCT with 3d early transition metals poses a significant challenge. Herein, we describe an unprecedented approach to allylic C(sp^(3))–H addition to aldehydes, employing chromium(Cr) complexes as catalysts through visible-light-induced LMCT. By investigating the reaction pathway through various mechanistic studies, including radical trapping, kinetic isotope effect(KIE) analysis, and transient absorption spectroscopy, valuable insights have been gained. The proposed mechanism suggests the intermediacy of bromine radicals through homolysis of the Cr–Br bond. Notably, this protocol expands our understanding of the photochemical properties of earth-abundant Cr complexes.展开更多
Exciton-polaritons offer the potential to achieve electrically pumped perovskite polariton lasers with much lower current thresholds than conventional photonic lasers. While optically pumped exciton-polaritons have be...Exciton-polaritons offer the potential to achieve electrically pumped perovskite polariton lasers with much lower current thresholds than conventional photonic lasers. While optically pumped exciton-polaritons have been widely studied in halide perovskites, electrically-pumped polaritons remain limited. In this study, we demonstrate the use of a solution-processing strategy to develop halide perovskite polariton light-emitting diodes(LEDs) that operate at room temperature. The strong coupling of excitons and cavity photons is confirmed through the dispersion relation from angle-resolved reflectivity, with a Rabi splitting energy of 64 meV. Our devices exhibit angle-resolved electroluminescence following the low polariton branch and achieve external quantum efficiencies of 1.7%, 3.85%, and 3.7% for detunings of 1.1,-77, and-128 meV, respectively. We also explore devices with higher efficiency of 5.37% and a narrower spectral bandwidth of 6.5 nm through the optimization of a top emitting electrode. Our work demonstrates, to our knowledge, the first room-temperature perovskite polariton LED with a typical vertical geometry and represents a significant step towards realizing electrically pumped perovskite polariton lasers.展开更多
基金supported by the National Natural Science Foundation of China (22001215, 22171231)WE-Syn Bio Center at Westlake University (WU2022A007)Zhejiang Leading Innovative and Entrepreneur Team Introduction Program (2020R01004)。
文摘Photoinduced ligand-to-metal charge transfer(LMCT) has emerged as an effective strategy for synthesizing organic molecules in a sustainable manner. However, the majority of existing reports on selective C(sp^(3))–H bond functionalization via photoinduced LMCT focus on the use of late transition metals or rare-earth metals for radical additions or cross-couplings. In contrast, the utilization of photoinduced LMCT with 3d early transition metals poses a significant challenge. Herein, we describe an unprecedented approach to allylic C(sp^(3))–H addition to aldehydes, employing chromium(Cr) complexes as catalysts through visible-light-induced LMCT. By investigating the reaction pathway through various mechanistic studies, including radical trapping, kinetic isotope effect(KIE) analysis, and transient absorption spectroscopy, valuable insights have been gained. The proposed mechanism suggests the intermediacy of bromine radicals through homolysis of the Cr–Br bond. Notably, this protocol expands our understanding of the photochemical properties of earth-abundant Cr complexes.
基金National Key Research and Development Program of China (2017YFA0207700)Outstanding Youth Fund of Zhejiang Natural Science Foundation(LR18F050001)National Natural Science Foundation of China (61804134, 61874096, 62074136)。
文摘Exciton-polaritons offer the potential to achieve electrically pumped perovskite polariton lasers with much lower current thresholds than conventional photonic lasers. While optically pumped exciton-polaritons have been widely studied in halide perovskites, electrically-pumped polaritons remain limited. In this study, we demonstrate the use of a solution-processing strategy to develop halide perovskite polariton light-emitting diodes(LEDs) that operate at room temperature. The strong coupling of excitons and cavity photons is confirmed through the dispersion relation from angle-resolved reflectivity, with a Rabi splitting energy of 64 meV. Our devices exhibit angle-resolved electroluminescence following the low polariton branch and achieve external quantum efficiencies of 1.7%, 3.85%, and 3.7% for detunings of 1.1,-77, and-128 meV, respectively. We also explore devices with higher efficiency of 5.37% and a narrower spectral bandwidth of 6.5 nm through the optimization of a top emitting electrode. Our work demonstrates, to our knowledge, the first room-temperature perovskite polariton LED with a typical vertical geometry and represents a significant step towards realizing electrically pumped perovskite polariton lasers.
