Tailoring Spin-Orbit Coupling by Aligned Earth-Abundant Metals for Extending Lifetime of Charge-Transfer Excited State

摘要

The long charge-transfer excited state (CTES) lifetime of organometal complexes make them very promising in the applications of photovoltaic, photocatalysis and photosensor. Employing the spin-orbit coupling (SOC) of noble metals for achieving long-lived CTES are often essential to guarantee high performance. There is much interest in replacing these noble metals with non-noble metals due to low cost and environmental friendliness. However, despite the exploration of advanced molecular designs, it is failing to access a long-lived CTES of earth-abundant metal-containing complexes by the SOC effect. Because weak ligand field splitting of non-noble metals causes rapid deactivation of CTES. Here, the SOC of orderly aligned non-noble metals on a layered double hydroxide (LDH) nanosheet is enhanced through the Rashba effect caused by breaking of the inversion symmetry. Taking porphyrins-Pd (Pd-TCPP) as a model chromophore, a series of (LDHs/Pd-TCPP)(n) films are fabricated, and a high polar distortion (alinged Pd-TCPP dipoles on LDH nanosheet) amplifies the signals of SOC sufficiently to realize a long-lived CTES. By virtue of designability of LDH elements, the lifetime of CTES can be regulated through changed interaction, assembly process, and charge-transfer path. Therefore, this strategy opens up new avenue for the application of earth-abundant metal in SOC effect-regulated optical devices and sensors.