Two-Photon, Three-Photon, Four-Photon Near-Infrared Quantum Cutting Luminescence of Er3+ Activator in Oxyfluoride Vitroceramics

Two-photon, three-photon, and four-photon near-infrared quantum cutting luminescence of Er3+: oxyfluoride vitroceramics are studied. X-ray diffraction, absorption, visible to near infrared luminescence and excitation spectra of Er3+-doped oxyfluoride vitroceramics have been measured. We found that when the concentration of the Er3+ ion increased from 0.5% to 2., the infrared excitation spectra intensities of the Er3+ ion enhanced by approximately 5.64, 4.26, 2.77, 7.31, 6.76, 4.75, 2.40, 11.14, 2. 88, and 4.61 times for the I-4(15/2)->(2)G(7/2), I-4(15/2)->(4)G(9/2), I-4(15/2)->(4)G(11/2), I-4(15/2)-> H-2(9/2), I-4(15/2)->(F-4(3/2), F-4(5/2)) I-4(15/2)-> F-4(7/2), I-4(15/2)-> H-2(11/2), I-4(15/2)-> S-4(3/2), I-4(15/2)-> F-4(9/2), and I-4(15/2)-> I-4(9/2) transitions. Meanwhile, it can also be found that the visible excitation spectra intensity of the Er3+ ion decreased by approximately 1. 36, 1.93, 3.43, 1.01, 2.24, and 2.28 times for the I-4(15/2)->(2)G(7/2), I-4(15/2)->(4)G(9/2), I-4(15/2)->(4)G(11/2), I-4(15/2)-> H-2(9/2), I-4(15/2)->(F-4(3/2), F-4(5/2)) and I-4(15/2)-> F-7/2 absorption transitions of the Er3+ ion, respectively. That is to say, the samples exhibited a 2 to 11 times enhancement in both infrared luminescence and excitation intensities, with a concomitant one to three times decreasing of both visible luminescence and excitation intensities. Moreover, the excitation spectra of 1 543. 0 and 550. 0 nm luminescence were very similar both in shape and peak wavelength, confirming that the multiphoton near-infrared quantum cutting luminescence phenomena were found. In order to analyze the process and mechanism of quantum cutting better, we measured the variation of main visible and infrared luminescence intensity based on the excitation intensity. It found that all visible and infrared luminescence intensity was linear depended on the excitation intensity basically. In which, the variation of the visible luminescence intensity depended on the excitation intensity was slightly larger than linear. It is resulted from the very small absorption of excited state. The variation of the infrared 1 543. 0 nm luminescence intensity depended on the excitation intensity was slightly smaller than linear. It is the characteristic phenomena of quantum cutting luminescence. It found that two-photon quantum cutting luminescence of I-4(9/2) state mainly resulted from the {I-4(9/2)-> I-4(13/2), I-4(15/2)-> I-4(13/2)} ETr31-ETa01 cross-energy transfer process. Three-photon quantum cutting luminescence of the S-4(3/2) state mainly result from the {S-4(3/2)-> I-4(9/2), I-4(15/2)-> I-4(13/2)} ETr31-ETa01 and {I-4(9/2)-> I-4(13/2), I-4(15/2)-> I-4(13/2)} ETr31-ETa01 cross-energy transfer process. Four-photon quantum cutting of H-2(9/2) mainly results from the {H-2(9/2)-> I-4(13/2), I-4(15/2), S-4(3/2)}ETr91-ETa05 {S-4(3/2)-> I-4(9/2), I-4(15/2)-> I-4(13/2)} ETr53-ETa05 and {I-4(9/2)-> I-4(13/2), I-4(15/2)-> I-4(13/2)} ETr31-ETa01 cross-energy transfer process. These measured results are useful for the next-generation of quantum cutting solar cells, a current hot point globally.