First-principles study lone-pair effects of Sb (III)-S chromophore influence on SHG response in quaternary potassium containing silver antimony sulfides

Compounds K2AgSbS4, KAg2SbS4 and K2Ag3Sb3S7 exhibit second-order NLO response: 15×, 30× and 62× times than that KDP (KH2PO4, d36=0.39 pm/V), respectively. First-principles methods reveal that the large SHG response of K2Ag3Sb3S7 is dominated by the Sb-S chromophore with lone pairs.262