Novel Routes to Europium Sulfide A thesis submitted to the University of Manchester for the Degree of Doctor of Philosophy in the Faculty of Science and Engineering 2018 Asma Majed H Alenad School of Chemistry/ The University of Manchester, Oxford Road Manchester, M13 9PL Contents Chapter 1 .................................................................................................................. 16 Introduction ............................................................................................................ 16 1.1 Classification of solids .................................................................................. 16 1.2 Semiconductors ............................................................................................. 17 1.2.1. Band structure ........................................................................................... 17 1.2.2 Band structure in different types of solids ................................................. 17 1.2.3 Intrinsic and extrinsic semiconductors .......................................................... 18 1.2.3.1 n-type doping .......................................................................................... 19 1.2.3.2 p-type doping .......................................................................................... 19 1.2.3.3 p-n junction ............................................................................................. 20 1.2.4 Direct and indirect semiconductors ........................................................... 21 1.2.5 Classification and applications of semiconductors .................................... 24 1.3 Nanoparticles ................................................................................................ 24 1.3.1 Properties of nanoparticles......................................................................... 26 1.3.1.1 Electronic properties of nanoparticles .................................................... 27 1.3.1.2 Magnetic properties of nanoparticles ...................................................... 28 1.3.2 Preparation of nanoparticles ...................................................................... 31 1.3.2.1 Formation mechanism of nanoparticles .................................................. 32 1.3.2.1.1 Nucleation ............................................................................................ 32 1.3.2.1.2 Growth ................................................................................................. 32 1.3.3 Stabilisation of nanoparticles ..................................................................... 33 1.3.3.1 Electrostatic stabilisation ........................................................................ 33 1.3.3.2 Steric stabilisation ................................................................................... 34 1.4 Lanthanide chemistry .................................................................................... 35 1.4.1 Europium chalcogenides ............................................................................ 37 1.4.1.1 Synthesis of europium chalcogenide complexes .................................... 38 1.4.1.2 Synthesis of europium chalcogenide nanocrystals ................................. 41 1.4.1.3 Synthesis of europium dioxide sulfide nanocrystals ............................... 48 1.4.1.4 Synthesis of europium sulfide nanoparticles .......................................... 50 1.4.2 Applications of europium chalcogenide nanomaterials ............................. 52 1.4.2.1 Optical properties of europium chalcogenide nanomaterials ................. 53 2 1.4.2.2 Magnetic properties of europium chalcogenides ........................................ 56 1.4.2.3 Magneto-Optical properties of europium chalcogenide nanomaterials .. 58 1.5 Aim and Scope of the this Thesis ................................................................ 61 1.6 References ..................................................................................................... 62 Chapter 2 .................................................................................................................. 67 Europium Chalcogenide Complexes ...................................................................... 67 2.1 Summary ....................................................................................................... 67 2.2 Introduction ................................................................................................... 68 2.3 Experimental ................................................................................................. 72 2.3.1 Instrumentation .......................................................................................... 72 2.3.2 Precursor Synthesis .................................................................................... 73 2.3.2.1 Synthesis of europium thiobenzoato complexes ..................................... 73 2.3.2.1.1 Synthesis of [Eu(C6H5COS)3(phen)2] (1) ............................................ 73 2.3.2.1.2 Synthesis of [Eu(C6H5COS)3(phen)]·CHCl3 (2s) ............................... 74 2.3.2.1.3 Synthesis of [Eu(C6H5COS)3(bipy)(MeOH)] (3s) .............................. 74 2.3.2.2 Synthesis of europium dithiocarbamato complexes ............................... 75 2.3.2.2.1 Synthesis of [Eu(S2CN(CH3)(C6H13))3(phen)] (4) ............................... 75 2.3.2.2.2 Synthesis of [Eu(S2CN(C6H13)2)3(phen)] (5) ....................................... 75 2.3.2.3 Synthesis of europium mono cation complexes ..................................... 76 2.3.2.3.1 Synthesis of intermediate tetraphenylphosphonium ethylxanthate ..... 76 2.3.2.3.2 Synthesis of intermediate tetraphenylphosphonium diethyldithiocarbamate........................................................................................ 77 2.3.2.3.3 Synthesis of (Ph4P)[Eu(S2COCH2CH3)4] (6) ....................................... 77 2.3.2.3.4 Synthesis of (Ph4P)[Eu(S2CN(CH2CH3)2 )4] (7) .................................. 77 2.3.2.4 Synthesis of europium thiophosphato complexes .................................. 78 2.3.2.4.1 Synthesis of [Eu(S2P(OCH2CH3)2)3(phen)] (8) ................................... 78 2.3.2.4.2 Synthesis of [Eu(S2P(OCH2CH3)2)3(bipy)] (9) .................................... 79 2.4 Results and Discussion ................................................................................. 79 2.4.1 Structural characterization of europium complexes .................................. 79 2.4.1.1 Single crystal X-ray structure of [Eu(C6H5COS)3(phen)2] (1), [Eu(C6H5COS)3(phen)]·CHCl3 (2s) and [Eu(C6H5COS)3(bipy)(MeOH)] (3s) .. 79 2.4.1.2 Single crystal X-ray structure of [Eu(S2CN(CH3)(C6H13))3(phen)] (4) and [Eu(S2CN(C6H13)2)3(phen)] (5) .................................................................... 87 3 2.4.1.3 Single crystal X-ray structure of (Ph4P)[Eu(S2COCH2CH3)4] (6) and (Ph4P)[Eu(S2CN(CH2CH3)2 )4] (7) ...................................................................... 93 2.4.1.4 Single crystal X-ray structure of [Eu(S2P(OCH2CH3)2)3(phen)] (8) and [Eu(S2P(OCH2CH3)2)3(bipy)] (9) ....................................................................... 97 2.5 Conclusion .................................................................................................. 102 2.6 Reference .................................................................................................... 104 Chapter 3 ................................................................................................................ 105 Synthesis of Eu2O2S and EuS nanoparticles ........................................................ 105 3.1 Summary ..................................................................................................... 105 3.2 Introduction ................................................................................................. 106 3.3 Experimental ............................................................................................... 109 3.3.1 Instrumentation ........................................................................................ 109 3.3.2 Precursor Synthesis .................................................................................. 110 3.3.3 Synthesis of EuS Nanoparticles ............................................................... 110 3.3.4 Thermolysis of [Eu(C6H5COS)3(phen)2] (1), [Eu(C6H5COS)3(phen)]·CHCl3 (2s) and [Eu(C6H5COS)3(bipy)(MeOH)] (3s) to form Eu2O2S nanoparticles ............................................................................... 110 3.4 Results and Discussion ............................................................................... 111 3.4.1 Characterization of EuS nanoparticles from (2s), (3s), (4), (5), (6) and (7) precursors .......................................................................................................... 111 3.4.1.1 Thermogravimetric analysis ................................................................. 111 3.4.1.2 Powder X-ray diffraction analysis ........................................................ 114 3.4.1.3 Size and morphology Characterization ................................................. 118 3.4.2 Characterization of Eu2O2S nanoparticles from (1), (2s) and (3s) Precursors.......................................................................................................... 126 3.4.2.1 Powder X-ray diffraction analysis ........................................................ 126 3.4.2.2 Size and morphology characterization .................................................