Optical limiter using a lead phthalocyanine

Abstract

The performance of an optical limiter based on Pb-tetrakis(cumylphenoxy)phthalocyanine, a robust organic material with a large χ(3) and figure of merit, χ(3)/α0, is described. In an f/5 limiter with a sample transmission of 0.68, the threshold for limiting was 8±2 nJ and the dynamic range was greater than a factor of 103. The threshold for the PbPc(CP)4 limiter was ∼15 times smaller and the high intensity transmission ∼4–5 times lower than an equivalent limiter based on a thermal nonlinearity.

Excitation of Highly Conjugated (Porphinato)palladium(II) and (Porphinato)platinum(II) Oligomers Produces Long-Lived, Triplet States at Unit Quantum Yield That Absorb Strongly over Broad Spectral Domains of the NIR

“…The early time-delay transient spectrum of PZn 3 ( Figure 3A) exhibits a NIR absorption band (λ max (S 1 f S n )) centered at 1120 nm; note that this transition is considerably broader (fwhm ) 750 cm -1 ) than that observed for the analogous early time PZn 2 NIR transient (fwhm ) 670 cm -1 ), and that the PZn 3 S 1 f S n spectra also feature a higher energy NIR absorption centered manifold at ∼980 nm. In contrast, for PPd 3 and PPt 3 the low energy transient absorption manifolds observed at t delay < 350 fs are significantly broader than that evinced for PZn 3 . In this regard, note that PPd 3 and PPt 3 feature prominent transient absorption maxima evident at 984 and ∼940 nm 85 ( Figure 3B,C), respectively; while these highest extinction S 1 f S n absorption manifolds are considerably blue-shifted relative to that of the PZn 3 benchmark, note that both PPd 3 and PPt 3 also display absorption manifolds that extend beyond 1100 nm.…”

“…51,84 It is important to note, however, that even at 77 K, phosphorescence for PPd n and PPt n is weak (phosphorescence quantum yields, φ p , were estimated by comparison to fluorescent (porphinato)zinc benchmarks to be below 5%). Note also that PPd 3 and PPt 3 also exhibit residual fluorescence (S 1 f S 0 ) bands (Table 1); excitation spectra evince that this fluorescence is authentic and does not derive from residual free-base impurities.…”

“…The electronic absorption spectral data acquired for PPd 2 , PPd 3 , PPt 2 , and PPt 3 ( Figure 1, Table 1) manifest the general spectroscopic characteristics delineated previously for the corresponding PZn 2 and PZn 3 benchmarks. Note that all of the PPd n and PPt n species display high oscillator strength Q-state derived low energy π-π* absorption bands, with a molar extinction coefficient exceeding 65 000 M -1 cm -1 for PPt 3 . The spectra in Figure 1 demonstrate that compared to the analogous PZn n spectroscopic benchmarks, the Q-state derived electronic absorption bands for the palladium and platinum derivatives are blue-shifted; this phenomenon is common to hypsoporphyrin species and has been attributed to efficient mixing of the porphyrin π* and metal nd π orbitals.…”

“…53,54, The syntheses of PPd 2 , PPd 3 , PPt 2 , and PPt 3 were accomplished through metal-mediated cross-coupling of appropriately brominated and meso-ethyne-functionalized (porphinato)zinc(II) precursors. 57,63,80,81 Scheme 1 highlights the synthetic route to the PPd 2 and PPt 2 structures, while the analogous path to the PPd 3 and PPt 3 species is shown in Scheme S1 of the Supporting Information. Following the syntheses of the parent PZn 2 and PZn 3 complexes, these species were demetalated to generate the corresponding free-base complexes (PFb n ).…”

“…The additional requirements of a long excited-state lifetime, high resistance to degradative photochemistry, and large magnitude nonlinear optical (NLO) response have made identification of OPL candidates based on RSA for the NIR difficult. In contrast, a wide variety of optical limiting materials based upon phthalocyanine, [3][4][5][6][7][8][9][10][11] porphyrin, [12][13][14] fullerene, [15][16][17][18][19][20] carbon nanotube, 9,[21][22][23][24][25] nanoparticle, [26][27][28][29][30][31][32][33][34] and other [35][36][37][38][39][40] motifs have been identified for the visible spectral region. The limited number of potential NIR OPL materials 39,[41][42][43][44][45][46][47]…”