Obviously, the LCs (WOBs, NOVs, Si=O states, and so on) could act as the sensitizers in the SROEr matrixes. For the investigation of the BAY 11-7082 chemical structure energy transfer from these GW3965 cell line sensitizers to Er3+, the PL spectra of Er3+ in the infrared band (4I15/2 to 4I13/2) were measured, as shown in Figure  4a. Interestingly, the PL signal from Er3+ could not be detected from the SROEr films annealed at <900°C, although the intense visible PL from the LCs (WOBs, NOVs, and Si=O states) can be observed. However, for the samples annealed above 900°C, the PL of Er3+ could be obviously resolved (its intensity increases significantly with the annealing temperatures). Therefore, the energy transfer from the NOVs could be excluded

since the NOVs selleck kinase inhibitor disappear after high-temperature annealing (1,150°C). Moreover, the sensitization of the temperature-dependent

PL of Er3+ from the WOBs could also be excluded due to their almost identical PL from the as-deposited and annealed SROEr films. Meanwhile, the evolution of the PL intensity from Er3+ is in accordance with that from the Si=O states at higher-annealing temperatures (≥900°C, the critical temperature that the Si NCs begin to precipitate in a great amount). Hence, we consider that the sensitization of Er3+ is mainly caused by the Si=O states in the SROEr matrix. According to the discussion above, the Si=O states would be induced greatly when the Si NCs precipitate in a great amount, and the energy transfer process between the Si=O states and Er3+ is

also controlled by the Si NCs in the SROEr matrix. The introduction of the Si NCs can not only enhance the luminescence of the Si=O states by facilitating the photon absorption of the Si=O states but also improve the PL of Er3+ by the energy transfer process of the Si=O states. Besides, the PL of Er3+ would also be enhanced by the activation of Er3+ in the SROEr films after high-temperature annealing (≥900°C). The PL intensity of Er3+ increased significantly when the annealing time increased from 30 to 120 min for the SROEr annealed at 1,150°C, as shown in Figure  4a. It means that further improvement of the PL property of Er3+ could be achieved by optimizing the annealing condition of the SROEr films. Figure 4 PL spectra of Er 3+ 2-hydroxyphytanoyl-CoA lyase ion and PLE spectra of both Er 3+ ion and Si=O states. (a) PL spectra of the Er3+ ions in the SROEr films with various annealing conditions. (b) Normalized PLE spectra of the Si=O states (collected at 2.2 eV) and Er3+ (collected at 0.8 eV) for the SROEr film annealed at 1,150°C for 30 min. To further determine the energy transfer mechanism in the SROEr films, the PLE spectra of the Si=O states (collected at 2.2 eV) and Er3+ (collected at 0.8 eV) for the SROEr film annealed at 1,150°C for 30 min were measured, as shown in Figure  4b, with the intensities normalized by their correspondingly maximal values.