Light-extraction enhancement of white LEDs with different phases of TiO 2 :0.01Eu 3+ spheres

Influence of Fe3+ ions on the optical properties and photocatalytic ability of spin coated Fe3+ doped brookite TiO2 thin films

“…During the past years titanium dioxide (TiO 2 ) thin films are widely investigated as a heterogeneous catalyst due to their stability, high resistance to photo-corrosion, strong oxidizing power, high photosensitivity, bio-compatibility, and nontoxic properties [1][2][3][4]. Titania has been considered an important candidate for environmental, opto-electronic, and micro-electronics applications such as photocatalyst [1,5], solar cells [6], microbial agent [7], LEDs [8], optical waveguides [9], optical coatings [10], capacitors [11], thin film transistors [12], photochromic devices [13], and gas sensors [14]. The direct optical band gap is 3 eV for rutile (tetragonal, space group (SG): 136, P4 2 /mnm, number of attoms per unit cell Z = 2), 3.2 eV for anatase (tetragonal, SG:141, I4 1 /amd, Z = 4) and 3.3 eV for brookite (orthorhombic, SG: 61, Pbcn, Z = 8) phases of TiO 2 [1,15,16], limits further practical application due to pure TiO 2 can absorb the ultraviolet (UV) light of the solar spectrum, when using solar light, which has an energy distribution of less than 5% for UV light.…”