Laser ablation synthesis of new gold phosphides using red phosphorus and nanogold as precursors. Laser desorption ionisation time-of-flight mass spectrometry

Gold phosphides show unique optical or semiconductor properties and there are extensive high technology applications, e.g. in laser diodes, etc. In spite of the various AuP structures known, the search for new materials is wide. Laser ablation synthesis is a promising screening and synthetic method. Generation of gold phosphides via laser ablation of red phosphorus and nanogold mixtures was studied using laser desorption ionisation time-of-flight mass spectrometry (LDI TOFMS). Gold clusters Aum+ (m = 1 to similar to 35) were observed with a difference of one gold atom and their intensities were in decreasing order with respect to m. For Pn+ (n = 2 to similar to 111) clusters, the intensities of odd-numbered phosphorus clusters are much higher than those for even-numbered phosphorus clusters. During ablation of P-nanogold mixtures, clusters Aum+ (m = 1-12), Pn+ (n = 2-7, 9, 11, 1333, 3595 (odd numbers)), AuPn+ (n = 1, 288 (even numbers)), Au2Pn+ (n = 1-7, 1416, 2151 (odd numbers)), Au3Pn+ (n = 1-6, 8, 9, 14), Au4Pn+ (n = 1-9, 1416), Au5Pn+ (n = 1-6, 14, 16), Au6Pn+ (n = 1-6), Au7Pn+ (n = 1-7), Au8Pn+ (n = 1-6, 8), Au9Pn+ (n = 1-10), Au10Pn+ (n = 1-8, 15), Au11Pn+ (n = 1-6), and Au12Pn+ (n = 1, 2, 4) were detected in positive ion mode. In negative ion mode, Aum (m = 15), Pn (n = 2, 3, 511, 1319, 2135, 39, 41, 47, 49, 55 (odd numbers)), AuPn (n = 46, 826, 3036 (even numbers), 48), Au2Pn (n = 25, 8, 11, 13, 15, 17), Au3Pn (n = 611, 32), Au4Pn (n = 1, 2, 4, 6, 10), Au6P5, and Au7P8 clusters were observed. In both modes, phosphorus-rich AumPn clusters prevailed. The first experimental evidence for formation of AuP60 and gold-covered phosphorus Au12Pn (n = 1, 2, 4) clusters is given. The new gold phosphides generated might inspire synthesis of new Au-P materials with specific properties. Copyright (C) 2012 John Wiley & Sons, Ltd.