Substituent effect on the photophysical and nonlinear optical characteristics of Si phthalocyanine - Detonated nanodiamond conjugated systems in solution

摘要

This work reports on the photophysical, nonlinear absorption and optical limiting properties of detonation nanodiamonds (DNDs)-silicon phthalocyanine nanoconjugate systems. Si(IV) hydroxide phthalocyanines employed are: 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyaninato (Si(OH)(2)TPPc), 2,9(10),16(17),23(24)-tetrakis-(4-tert-butyl) phthalocyanato (Si(OH)(2)TBPc) and phthalocyanato(Si(OH)(2)Pc). Pcs were covalently linked to nanondiamonds and investigated using 532 nm laser excitation at 7 ns pulses for their optical limiting properties. Si(OH)(2)TBPc and Si(OH)(2)Pc gave larger triplet quantum yields when linked to DNDs, while the value decreased for Si(OH)(2)TPPc in the presence of DNDs due to aggregation. However all Pcs showed enhanced nonlinear optical properties in the presence of DNDs. DNDs-Si(OH)(2)TPPc and DNDs-Si (OH)(2)TBPc gave the highest imaginary third-order susceptibility (I-m[X-(3)]) and hyperpolarizability (gamma) at 5.19 x 10(-8) and 3.85 x 10(-8) esu and 2.66 x 10(-27) and 1.97 x 10(-27) esu, respectively. DNDs-Si(OH)(2)TBPc nanoconjugates showed lowest limiting threshold (I-lim) value of 0.01 J.cm(-2) relative to 0.09 for DNDs-Si (OH)(2)TPPc.