Rb2Sn4Q9 (Q = S and Se): Low-Dimensional Noncentrosymmetric Chalcogenides with High Laser-Induced Damage Threshold

초록

Low-dimensional chalcogenides have shown promising nonlinear optical (NLO) responses in the infrared region. Rb(2)Sn(4)Q(9) (Q = S and Se) crystallizes in the noncentrosymmetric orthorhombic space group P2(1)2(1)2(1). These compounds comprise an anionic layer of [Sn(4)Q(9)](2-) chains separated by the Rb atoms located between the layers. Differential thermal analysis shows that Rb2Sn4Se9 melts congruently, having a melting point temperature of 472 degrees C and a crystallization temperature of 443 degrees C and no observable phase transitions, making them promising for large crystal growth. These compounds' air- and water-stability make them more viable for application compared to the challenges faced in other promising NLO materials like gamma-NaAsSe2. The Rb2Sn4S9 and Rb2Sn4Se9 have energy band gaps of 2.56 and 1.75 eV, respectively. Second harmonic generation from Rb(2)Sn(4)Q(9) was found to be nonphase matchable for particle size above 75 mu m, with Rb2Sn4Se9 having a chi((2)) = 36.7 +/- 7.4 pm/V at 1800 nm. Both materials show a high laser-induced damage threshold (LIDT) of 1.8 GW/cm(2) and 0.2 GW/cm(2) for the sulfide and selenide compounds, respectively, which are significantly larger than that of the benchmark reference material, AgGaSe2 (0.1 GW/cm(2)). The high LIDT values make these materials promising for NLO applications involving intense light-matter interactions..

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