Site-Selective Excitation of “Exciplex Tuning” for Luminescent Nanoclusters of Dicyanoargentate(I) Ions Doped in Different Alkali Halide Crystals

Abstract

Luminescent nanoclusters of linear dicyanoargentate(I) ions doped in different alkali halide single crystals (NaF, NaCl, NaBr, and KCl) have been investigated. Site-selective excitation of the different nanoclusters results in the appearance of emission bands which are assigned to different luminescent {[Ag(CN)2]−} n nanoclusters in the host lattices. The nanoclusters of [Ag(CN)2]− in the alkali halides display energy tunability over a wide wavelength interval. The ab initio DFT calculations show that for nanoclusters, the first excited state has a deeper potential and shorter internuclear separation than the nanocluster ground state, indicative of excimer/exciplex behavior. Molecular modeling indicates how the distribution of nanoclusters varies with the host lattice. This emission energy tunability makes these systems attractive candidates for potential applications, such as tunable solid state lasers, photocatalysts, and photosensitizers for water splitting.

Considerable Enhancement of Emission Yields of [Au(CN)2–] Oligomers in Aqueous Solutions by Coexisting Cations

“…19−22 Detectable emissions with Au−Au bond formation have been observed even in intermolecular systems in solutions; i.e., [Au(CN) 2 − ], one of the simplest Au(I) complexes, exhibits emission after excited-state Au−Au bond formation in oligomers. 3,23,24 Patterson and co-workers performed pioneer studies of the excited-state oligomers of Au(I) complexes, including detailed studies of the emissions in solutions 3,[9][10][11]17,25,26 and solid states 10,25,27 as well as their applications. 9,10,17,23,28 In particular, light-emitting molecular assemblies with flexible structures and large oligomers such as oligomers larger than tetramers were observed in [Au(CN) 2 − ] n aqueous solutions.…”

“…3,23,24 Patterson and co-workers performed pioneer studies of the excited-state oligomers of Au(I) complexes, including detailed studies of the emissions in solutions 3,[9][10][11]17,25,26 and solid states 10,25,27 as well as their applications. 9,10,17,23,28 In particular, light-emitting molecular assemblies with flexible structures and large oligomers such as oligomers larger than tetramers were observed in [Au(CN) 2 − ] n aqueous solutions. Such flexibility and large size are unique points of the oligomers in fluid media because their formations require large displacements of gold atoms and such a large change will be difficult to achieve in solid states.…”

“…Such excited states often exhibit detectable excimer/exciplex emissions. Hence, the light emitting properties of Au­(I) complexes are dominated by the alignment or position of Au atoms and therefore attractive in various applications concerning photochemistry and photophysics, such as a tunable emitter, − bright-emitting devices, − sensing probes, ,− and mechanochromic phosphors. − …”

A Review of Luminescent Anionic Nano System: d10 Metallocyanide Excimers and Exciplexes in Alkali Halide Hosts

“…The crystal structure results show that the Ag–Ag bond distance is 3.11 Å and the low energy Ag–Ag vibrational frequency of about 75–125 cm −1 given by Raman indicates the presence of direct argentophilic interaction in Tl[Ag(CN) 2 ]. Since then, our group has reported a series of d 10 metal cyano compounds in nano systems [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. We found that due to the formation of different size exciplexes, these nano systems show interesting photophysical and photochemical behaviors, such as emission tunability, thermochromism, and optical memory.…”

Photophysical Investigation of Silver/Gold Dicyanometallates and Tetramethylammonium Networks: An Experimental and Theoretical Investigation

“…The conflicting photophysical behavior between the Au and Ag complexes made assignment of the emission bands difficult based solely on previously reported [Au(CN) 2 ] – /[Ag(CN) 2 ] – systems , , . As mentioned, emission in these systems can arise from a localized MLCT, a MMLCT, or MC transition.…”