Visible‐Light Harvesting with Cyclometalated Iridium(III) Complexes Having Long‐Lived ³IL Excited States and Their Application in Triplet–Triplet‐Annihilation Based Upconversion

Abstract

Cyclometalated iridium(III) complexes with intense absorption in the visible region (ε = 70920 M -1 cm -1 at 466 nm) were prepared by incorporating light-harvesting coumarin into the diimine ligand (for comparison: ε = 7030 M -1 cm -1 at 371 nm for the model diimine complex without light-harvesting ability). The complexes feature long-lived intraligand triplet excited states ( 3 IL, supported by spin density analysis of the triplet state). At room temperature, lifetimes, τ T , are up to 75.5 μs, as determined by nanosecond time-resolved transient absorption spectroscopy. Despite the weak phosphorescence (Φ P = 0.6-0.7 %) observed for the complexes, the triplet excited state (T 1 ) was demonstrated to be efficiently

Long‐Lived Room‐Temperature Near‐IR Phosphorescence of BODIPY in a Visible‐Light‐Harvesting N^C^N PtII–Acetylide Complex with a Directly Metalated BODIPY Chromophore

“…[14, [16][17][18][19][20] However, the photophysics of these dyads are very often elusive; for example, the phosphorescence was quenched and short T 1 lifetimes were observed when perylenediimide (PDI) and boron-dipyrromethene (BODIPY) were used for the preparation of Pt II and Ir III complexes. [21,22] On the other hand, BODIPY is a particularly interesting chromophore, [23,24] and has been incorporated into Pt II , Ru II , and Ir III complexes to afford visible-light harvesting and long-lived T 1 excited states.…”

An N^N Platinum(II) Bis(acetylide) Complex with Naphthalimide and Pyrene Ligands: Synthesis, Photophysical Properties, and Application in Triplet–Triplet Annihilation Upconversion

“…Compared to the emission at room temperature, the phosphorescence bands of the three complexes were all slightly blueshifted at 77 K, and this is attributed to a thermally induced Stokes shift (Δ E s ). The small values of Δ E s (0.033, 0.020, and 0.036 eV for Pt‐NI‐Py, Pt‐NI, and Pt‐Py, respectively) exclude a charge‐transfer emissive triplet state and reveal triplet intraligand ( 3 IL) excited‐state assignments , . The phosphorescence lifetime at 77 K was three times longer than that measured at room temperature (Table ).…”

Dicyanovinyl-unit-induced absorption enhancement of iridium(III) complexes in long-wavelength range and potential application in dye-sensitized solar cells

“…For most of them, the absorption response them is less than 400 nm [5]. Recently, several iridium complexes have been documented to show enhanced absorption capacity, from 400 to 500 nm, by modifying phenylpyridine ligand with oligothiophene pendants [7] or oligofluorene segment [8], or using 7-diethyaminocoumarine auxiliary ligand [9], etc.…”