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Ultraviolet (UV)-ozone photo-annealing was applied to fabricate low-temperature high-performance solution-processed thin-film transistors (TFTs). With UV-ozone treatment at the optimal temperature of 300 °C, TFT devices showed an improved field-effect mobility of 1.73 cm2 V−1 s−1, a subthreshold slope (S) of 0.32 V dec−1, an on/off-current ratio greater than 1.3 × 107, and good operational bias-stress stability compared to those of InGaZnO TFT devices fabricated with only a conventional thermal-annealing process. The results of X-ray photoelectron spectroscopy and the maximum density of the surface states (Ns) confirm that the device improvement originates from reduced oxygen-related defects and improved electron trapping due to UV-ozone irradiation.

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CaLa 2 ͑MoO 4 ͒ 4 :Sm 3+ ,Eu 3+ phosphors are prepared using a convenient solid-state reaction route. The red emission intensity of Eu 3+ is enhanced by Sm 3+ ion codoping. The energy transfer mechanism from Sm 3+ to Eu 3+ was found to be a dipole-quadrupole interaction with a critical distance of 10.42 Å. With increasing Eu 3+ doping content, the energy transfer efficiency ͑Sm 3+ → Eu 3+ ͒ gradually increased to 75.5%. The thermal quenching behavior was investigated using absorption and emission spectra. The thermal quenching temperature ͑T 50 ͒ of CaLa 2 ͑MoO 4 ͒ 4 :Sm 3+ ,Eu 3+ phosphors is above 200°C, and the activation energy of the thermal quenching process is 0.13 eV. The effect of codoped Sm 3+ ions on the thermal stability of CaLa 2 ͑MoO 4 ͒ 4 :Sm 3+ ,Eu 3+ phosphors is investigated.Many important commercial phosphors are based on rare-earth ions. They are frequently applied in very demanding applications such as light emitting diodes ͑LEDs͒. Phosphor-converted LEDs ͑pc-LEDs͒ have many advantages including low cost, simple fabrication, and easy driving. 1 Phosphors play a key role in the development of white-LEDs ͑WLEDs͒. Commercialized pc-WLEDs are usually assembled using the combination of a blue LED and a yellow phosphor yttrium aluminum garnet: Ce 3+ . However, such WLEDs cannot achieve low color temperatures with a high color rendering index because they lack red light in the LED spectrum. 2 The solution to this problem is to add a red phosphor for blue light excitation or to excite red, green, and blue phosphors using near-UV LEDs. Commonly used red-emitting phosphors for near-UV LEDs and blue LEDs are Y 2 O 2 S:Eu 3+ and CaS:Eu 2+ , respectively. However, sulfide-based phosphors have low thermal and chemical stability, and high toxicity. 3,4 Good thermal stability is one of the most important requirements for phosphors applied to pc-WLEDs because the junction temperature of typical LEDs can be above 100°C ͑Ref. 5͒ and the temperature effect greatly influences the light output and color rendering index. Often, the potential application of a phosphor for pc-WLEDs is determined and evaluated using the temperature dependence of luminescent intensity. Therefore, the development of a suitable red phosphor material and an understanding of its thermal quenching behavior for WLEDs are necessary.In this work, Eu 3+ doped in a molybdate host with a scheelite structure was chosen as the red-emitting phosphor because it can be excited at the near-UV or blue light region. It also exhibits chemical and physical properties that are more stable than those of the wellknown Y 2 O 2 S:Eu 3+ red phosphor. 4,6,7 Molybdate with a scheelite structure is thus a good host material for the red-emitting phosphor. Because the maximum efficiency of near-UV LEDs ͑emitting a wavelength of 370-410 nm, e.g., InGaN LEDs͒ is at around 400 nm, Eu 3+ -doped phosphors are usually codoped with Sm 3+ ͑as a sensitizer͒ to enhance the red emission intensity of Eu 3+ and to improve absorption at around 400 nm. An energy transfer efficiency...