Luminescent Materials: A Quantum Chemical Approach for Computer-Aided Discovery and Design (Springer Series in Materials Science, 322)

This book describes a unique combination of quantum chemical methods for calculating the basic physical properties of luminescent materials, or phosphors. These solid inorganic materials containing an optically active dopant are key players in several major fields of societal interest, including energy-efficient lighting, solar cells, and medical imaging. The novel ab initio methods described in this book are especially designed to target the crowded and complex electronic excited states of lanthanide activators in inorganic solids. The book is well suited to both new and experienced researchers alike and appeals to a broad range of theoretical and experimental backgrounds. The material presented enables an adept understanding of elaborate calculations, which, in tandem with experiments, give essential insight into difficult luminescence problems and quandaries, thus fully preparing the reader for an educated search for new functional luminescent materials Foreword Preface Contents Acronyms Part I Multiconfigurational Ab Initio Embedded-Cluster Methods for Luminescent Materials 1 Quantum Chemistry Methods 1.1 Crowded Manifolds of Local Excited States of Luminescent 1.2 Embedded-Cluster Approximation for Local Properties of Materials 1.2.1 Self-Consistent Embedded Ions (SCEI) Calculations 1.2.2 Relaxation and Polarization of the Cluster Environment 1.3 Relativistic Effects for Lanthanides and Other Heavy Elements 1.3.1 Douglas-Kroll-Hess Relativistic Hamiltonian 1.3.2 Spin-Orbit Coupling Hamiltonian 1.4 Electron Correlation for Rich and Crowded Manifolds of Excited States 1.4.1 Static Correlation and Multiconfigurational Expansions: CASSCF and RASSCF 1.4.2 Static Plus Dynamic Correlation and Multi-references: CASPT2 and RASPT2 1.5 Electron Correlation and Spin-Orbit Coupling Together: RASSI-SO References 2 Feasibility and Accuracy: Criteria and Choices 2.1 Gaussian Basis Sets 2.1.1 Orthogonalization Functions 2.1.2 Interstitial Functions 2.2 Host Embedding Potentials 2.3 Multiconfigurational Expansions of Many-Electron Wave Functions 2.3.1 Restricting Spin Multiplicities of the Wave Functions 2.3.2 Criteria to Define the Restricted Active Space and the Target States in SA-RASSCF Calculations 2.4 Double-Shell Effect in Lanthanides: 4f Radial Correlation References 3 Calculations of Local Properties of Luminescent Materials 3.1 Potential Energy Surfaces and Curves 3.1.1 Ground and Excited State Local Structures and Vibrations 3.1.2 State Energy Differences and Potential Energy Crossings 3.2 Oscillator Strengths and Spontaneous Emission Lifetimes 3.3 Absorption and Emission Spectra Profiles References Part II Tutorial: Performing Ab Initio Calculations on Complex Manifolds of Excited States of Lanthanides in Solids 4 Symmetry Handling 4.1 Group and Representation Theoretical Ingredients 4.1.1 Definitions 4.1.2 Representations 4.1.3 Symmetry Group 4.1.4 Spherical Symmetry 4.1.5 Discrete Symmetry 4.1.6 Double Point Groups 4.2 Crystal Field Theory from a Representation Theoretical Perspective 4.2.1 Weak Crystal Field 4.2.2 Intermediate Crystal Field 4.2.3 Strong Crystal Field 4.3 Example: Pr3+ in BaF2 4.3.1 Connecting Oh with D2h Irreps 4.3.2 Symmetry of Molecular Orbitals 4.3.3 Active Space 4.3.4 Spin-Free Roots 4.3.5 Spin-Orbit Coupling References 5 Configuration Coordinate Energy Diagrams of Optically Active Sites in BaF2 5.1 The Project Directory 5.2 4f1 and 5d1 States of Ce3+ and 4f0 State of Ce4+ in BaF2 5.2.1 Calculating One- and Two-Electron Integrals with seward 5.2.2 Obtaining Good Initial Orbitals for Multireference Wave Function Calculations 5.2.3 Performing CASSCF Calculations 5.2.4 Performing Multi-State CASPT2 Calculations 5.2.5 Performing RASSI-Spin-Orbit Calculations 5.3 4f2 and 4f15d1 States of Pr3+ and 4f1 and 5d1 States of Pr4+ in BaF2 5.3.1 Calculating One- and Two-Electron Integrals with seward 5.3.2 Initial Orbitals 5.3.3 Performing CASSCF Calculations 5.3.4 Performing Multi-state CASPT2 Calculations 5.3.5 Performing RASSI-Spin-Orbit Calculations References Part III Excited State Manifolds of Luminescent Materials 6 Impurity States 6.1 4fN Manifolds 6.1.1 4f1 Manifold of Ce3+ 6.1.2 4f2 Manifold of Pr3+ 6.1.3 4f5 Manifold of Sm3+ 6.1.4 4f6 Manifold of Sm2+ 6.1.5 4f6 Manifold of Eu3+ 6.1.6 4f7 Manifold of Eu2+ 6.1.7 4f13 Manifold 6.2 4fN-15d Manifolds 6.2.1 5d1 Manifold of Ce3+ 6.2.2 4f5d Manifold of Pr3+ 6.2.3 4f55d Manifold of Sm2+ 6.2.4 4f65d Manifold of Eu2+ 6.2.5 4f125d Manifold of Tm2+ 6.2.6 4f135d Manifold of Yb2+ 6.3 4fN-16s and Impurity-Trapped-Exciton Manifolds 6.3.1 Impurity-Trapped-Exciton of Ce3+ 6.3.2 4f6s and 4fφITE Manifolds of Pr3+ 6.3.3 4f6φITE Manifold of Eu2+ 6.3.4 4f136s and 4f13φITE Manifolds of Yb2+ References 7 Charge Transfer States 7.1 Ligand-to-Metal Charge Transfer LMCT 7.1.1 LMCT States of CaTiO3 and CaZrO3 7.2 Inter-Valence Charge Transfer IVCT 7.3 Metal-to-Metal Charge Transfer MMCT 7.4 Ab Initio Diabatic IVCT and MMCT Configuration Coordinate Diagrams 7.4.1 Adiabatic Potential Energy Surfaces 7.4.2 Diabatic Potential Energy Surfaces 7.5 Empirical IVCT and MMCT Diagrams References Part IV Fundamental Studies on Luminescence 8 Solid-State Lighting Phosphors 8.1 Ce-Doped Yttrium Aluminum Garnet 8.2 Search for Red Phosphors 8.2.1 Ce3+-Doped Garnets 8.2.2 Bi-doped SrB4O7 8.2.3 Pr-Doped CaTiO3 and CaZrO3 References 9 Fundamental Spectroscopic Studies 9.1 Ce3+ in Elpasolites, Garnets, and Other Hosts 9.2 Pr3+ in CaF2 9.3 Sm3+ and Sm2+ in CaF2 9.4 Eu2+ and Eu3+ in Fluorides and Sulfides 9.4.1 4f6 Manifold of Eu3+ 9.4.2 4f7 Manifold of Eu2+ 9.4.3 4f65d Manifold of Eu2+ 9.5 Tm2+ in Halide Perovskites 9.6 Yb2+ in SrCl2 9.7 Actinide Ions in Hosts 9.7.1 Pa4+ in Cs2ZrCl6 9.7.2 U4+ in Cs2ZrCl6 and Cs2GeF6 9.7.3 U3+ in Cs2NaYCl6 References Part V Insights into the Complexity of Luminescent Materials 10 Active Centers of Luminescent Materials 10.1 Bond Length Changes upon 4frightarrow5d Excitations 10.2 Defects Mutually Attract Each Other and Distribute In-Homogeneously 10.3 Pauli Antisymmetry Interactions Between Host and Active Center 10.3.1 Red Shift of YAG:Ce3+d-f Emission upon Co-doping with La3+ 10.3.2 Multiplets of the Cr3+ R1-Line: Controlling Pauli Antisymmetry Strength 10.4 4fN-16s States Rise Their Energies in Hosts with Respect to Free-Ions 10.5 The Excited States of Eu-Doped Luminescent Materials References 11 Electron Transfer and Luminescence 11.1 Role of LMCT States in the Color Control of Pr Luminescence 11.2 IVCT States of Mixed-Valence Lanthanide-Activated Phosphors 11.2.1 Role of IVCT States in the Complex Interplay Between Regular and Anomalous Emission of Yb2+ in Fluorite-Type Hosts 11.2.2 Anomalous Emission of Ce3+ in Elpasolite Hosts 11.2.3 Anomalous Red and Infrared Emission of Ce3+ in SrS 11.2.4 IR Laser Induced Broadband Anti-Stokes White Emission of Sr2CeO4 11.2.5 Direct Evidence of IVCT States of Eu-Doped Luminescent Materials 11.2.6 Invariance of IVCT Absorption Onset Across the Lanthanide Series 11.3 MMCT States of Co-doped Lanthanide-Activated Phosphors 11.3.1 Broadband Infrared LEDs Based on Europium-to-Terbium Charge Transfer Luminescence 11.3.2 Charge Transfer from Eu2+ to Trivalent Lanthanide Co-Dopants: Systematic Behavior Across the Series 11.4 Role of Compensator-to-Dopant Charge Transfer in the Complex ... References Introduction -- Ab initio multiconfigurational embedded cluster methods for luminescent materials.-Tutorial: Performing ab initio calculations on complex manifolds of excited states of lanthanides in solids -- Excited state manifolds of luminescent materials -- Fundamental studies on luminescence -- Many-electron state energy diagrams of activators in hosts -- Prospect: Towards computational design of luminescent materials