Er3+-incorporated NaTi2(PO4)3 and its NIR to VIS photon upconversion properties

Abstract

Lanthanide-doped materials, known for their unique nonlinear optical properties through upconversion (UC), exhibit considerable potential for various applications. However, new hosts are required to address the limitations of conventional UC materials by enhancing efficiency and stability, while facilitating innovative multifunctional applications. In this paper, we introduce Er3+-incorporated NaTi2(PO4)3 (E-NTPO), synthesized using the solid-state reaction method, and elucidate its UC photophysical properties. To our knowledge, this is the first report exploring NTPO as a UC host material. The E-NTPO exhibits bright green emission, with its emission characteristics significantly influenced by the dopant concentration. Increasing the Er3+ content notably affects both the emission intensity and the spectral distribution of UC. Based on dopant concentration and excitation power, a trend of varying red-to-green emission ratios is observed. Furthermore, the intriguing decay time of approximately 2 mu s suggests that complex cross-relaxation processes are involved in the UC emission. Our findings emphasize the crucial role of the oxide host in elucidating lanthanide UC physics and imply potential applications across various UC contexts.