Abstract
We present experimental evidence for cooperative energy transfer from to two ions and a determination of the energy-transfer rate. Energy transfer from to was investigated by luminescence measurements on doped with 1% . Time-resolved luminescence experiments were analyzed using Monte Carlo simulations based on theories for phonon-assisted, cooperative, and accretive energy transfer. The luminescence decay curves of the emission from show an excellent agreement with simulations based on cooperative energy transfer via dipole-dipole interaction, while a phonon-assisted or an accretive energy-transfer mechanism cannot explain the experimental results. The energy-transfer rate to two nearest-neighbor ions is . This corresponds to an upper limit of the energy-transfer efficiency of 88% in . Application of cooperative energy transfer has prospects for increasing the energy efficiency of crystalline Si solar cells by photon doubling of the high energy part of the solar spectrum.
2 More- Received 10 May 2004
DOI:https://doi.org/10.1103/PhysRevB.71.014119
©2005 American Physical Society