On the efficient Te4+→Yb3+ cooperative energy transfer mechanism in tellurite glasses: A potential material for luminescent solar concentrators

• Autor(a) principal: Rufino Souza, Ana Kely
• Data de Publicação: 2019
• Outros Autores: Langaro, Ana Paula, Silva, Junior Reis, Costa, Francine Bettio [UNESP], Yukimitu, Keizo [UNESP], Silos Moraes, João Carlos [UNESP], Antonio de Oliveira Nunes, Luiz, Humberto da Cunha Andrade, Luis, Lima, Sandro Marcio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.jallcom.2018.12.038; http://hdl.handle.net/11449/189960
• topic: Cooperative energy transfer; Down-conversion; Te4+ ions; Tellurite glass; Thermal lens effect; Yb3+ ions

Te4+/Yb3+ co-doped 80%TeO2–20%Li2O glasses (amounts in mol%) were prepared by the conventional melt-quenching method in an ambient atmosphere, in order to investigate their optical characteristics for application in solar cells. An efficient near-infrared down-conversion mechanism was observed in these samples, involving the emission of two near infrared photons (at around 978 nm) after the absorption of one photon in the ultraviolet-blue region. This effect occurred by means of a process of cooperative energy transfer (CET) from Te4+ to Yb3+ ions. The CET efficiency (ηCET) was calculated from radiative transitions (lifetime) and also by a new method, developed in this work, based on rate equations quantifying the non-radiative transitions (thermal effect) involved in the system. The two methods showed very good agreement, with ηCET between 82 and 100% obtained for the sample prepared using a higher Yb3+ concentration (4 mol%). The results suggested that these tellurite materials could have potential applications in improving the efficiency of silicon-based solar cells.