Side-Emitting Optical Fibers of Colloidal Quantum Wells for Application in Curved-Surface Lighting and Sensing

As specialized optical fibers, side-emitting optical fibers (SEOFs) are designed to emit light from their sides rather than their ends for possible applications in curved-surface lighting and sensing. In this study, we propose and demonstrate an in situ decoration of SEOFs with colloidal quantum wells (CQWs) for the first time. The proposed method enables the homogeneous distribution of CQWs in the polymeric matrix of the fiber with high side-emission efficiency, which is based on a simple yet effective method of CQW sheet coating. Two different structures of CQWs, a red-emitting CdSe/CdZnS core/shell and a green-emitting CdSe/CdS core/crown, were synthesized and employed in SEOFs. Accordingly, carefully tuned concentrations of CQWs were incorporated within the hollow-core optical fibers, and the side-scattered light from the fibers was systematically characterized and analyzed. The results confirm excellent side-emitting characteristics that are highly dependent on the optical fiber structure and CQW absorption spectrum. The average quantum yield values of 51 ± 5% and 34.5 ± 5% for different concentrations of red and green CQWs relative to their solution form were measured in our experiment, which is associated with polymeric medium, cluster formation, and fiber tower temperature. The findings pave the way for developing high-performance optical fiber devices based on CQW-doped SEOFs capable of efficient and precise light emission targeting a wide variety of applications ranging from three-dimensional curved-surface lighting to sensing.