A Review on Optical Applications, Prospects, and Challenges of Rare-Earth Oxides

In small- and large-scale industries, manipulable optical characteristics are desired. In this regard, rare-earth oxides (REOs) have been providing pragmatic attributes in terms of successful implementations and promising prospects throughout the last few decades. Currently, there is no comprehensive literature review on REOs that can aid researchers in focusing on industry-relevant emerging materials. Therefore, this review reports studies that have been able to experimentally utilize the physical, chemical, thermal, electronic, spectroscopic, and photocatalytic properties of REOs in the optical field. The brief and focused review finds that the most pronounced applications of REOs in the optical field are in white light and laser, while the prospective ground likely lies in optoelectronics, fiber optic applications, and miscellaneous repertoires that incorporate an innovative utilization of an electronic configuration of REOs. From the perspective of this review, the versatility of an REO in the optical field has become prominent and quantified by the successful implementations of REOs in white light and nonwhite light applications. Furthermore, the innovative applications of REOs include but are not limited to the development of solid-state optical devices, optoelectronic systems, and photocatalytic agents. Specifically, their futuristic applications are likely to be led by the development of stronger emission devices and the obtaining of flexible doping characteristics by several ions such as Li+, Eu3+, Dy3+, Nd3+, La3+, Yb3+, etc. at different levels, which will render the pathway for further exploration in this regard. However, the improvement in terms of methodological attributes requires a serious consideration of overcoming the limitation of thermal stability, lack of exploration of several types of lights, photodarkening in critical applications, lack of applicability at a wide range of temperatures, and so on. From an industrial perspective, it can be conjectured from the reported literature that the challenges will be overcome at a large scale within a few years due to the expedited technological advancements of the experimental repertoires, rendering the REO applications in the optical field reasonably economic and commercially viable. In short, this is the first review that objectively considers the applications and prospects of REOs, which will essentially invoke several studies to investigate the specific properties and viability of REOs in the optical field.