Promoting luminescence of Yb/Er codoped ferroelectric composite by polarization engineering for optoelectronic applications

Ferroelectric oxide nanocrystals, in combination with the robust coupling of an electric field with crystal structure symmetry, makes such systems agreeable to field-induced crystal structural transformation. The luminescent properties of rare earth ions are sensitive to the symmetry of the surrounding crystal field. The luminescence tuning of rare earth ions is an important assignment in the research of luminescent materials. However, the current conditional feasibility and reversibility in the exploration of luminescence modification remain major challenges. In this article, the luminescence modulation of rare earth ions has been developed in Yb3+/Er3+ codoped ferroelectrics glass ceramics containing Bi4Ti3O12 nanocrystals through an electric field. The inclusion of nanocrystals in the glass matrix greatly enhances the electrical resistance. Both upconversion and near-infrared emissions of rare earth ions are effectively enhanced more than twice via polarization engineering. The electric field regulates the photonic properties of rare earth ions with excellent reversibility and nonvolatility in ferroelectrics. The effective modification by electric field provides a new scheme for optical storage and optoelectronic devices

Photonics and Optoelectronics of Low-Dimensional Materials

201812 bcrcVersion of RecordPublishe

Boosting the efficiency of quantum dot–sensitized solar cells over 15% through light‐harvesting enhancement

Abstract How to improve the capacity of light‐harvesting is still an important point and essential strategy for the assembling of high‐efficiency quantum dot–sensitized solar cells (QDSCs). A believable approach is to implant new light absorption materials into QDSCs to stimulate the charge transfer. Herein, the few‐layer black phosphorus quantum dots (BPQDs) are synthesized by electrochemical intercalation technology using bulk BP as source. Then the obtained BPQDs are deposited onto the surface of Zn–Cu–In–S–Se (ZCISSe) QD‐sensitized TiO2 substrate to serve as another light‐harvesting material for the first time. The experimental results have shown that BPQDs can not only increase the absorption intensity by photoanode but also reduce unnecessary charge recombination processes at the interface of photoanode/electrolyte. Through optimizing the size and deposition process of BPQDs, the champion power conversion efficiency of ZCISSe QDSCs is increased to 15.66% (26.88 mA/cm2, Voc = 0.816 V, fill factor [FF] = 0.714) when compared with the original value of 14.11% (Jsc = 25.41 mA/cm2, Voc = 0.779 V, FF = 0.713)

All-inorganic luminescent solar concentrator based on transparent multicomponent glasses embedded with PbSe QDs

International audienceLuminescent solar concentrators (LSCs) have become a seminal technology with the possibility of producing carbon–neutral buildings. However, current LSCs developed based on organic or organic–inorganic strategies face limited long-term outdoor stability. Here we developed an inorganic PbSe QDs glass with a strong UV absorption, large Stokes shift, broadband excitation and emission, and high transparency in the visible range. In addition, the suitability of inorganic PbSe quantum dots (QDs) glasses for use in LSCs as both transparent matrix and luminophore, as an alternative to the combination scheme of organic dyes or colloidal QDs and organic polymer materials was explored. Coupled with a commercial silicon solar cell, the as-prepared transparent LSC exhibited an optical efficiency of 10.13 % and a power conversion efficiency of 1.59 % under standard sunlight. These results demonstrate a new strategy to fabricate stable all-inorganic transparent LSCs for building integrated photovoltaic systems

Lanthanide Nd ion-doped two-dimensional In2Se3 nanosheets with near-infrared luminescence property

Ultrathin two-dimensional (2D) materials have drawn great attention in recent years due to their promising applications in biomedicine and atomically optoelectronic devices. In this work, we have fabricated a 2D In2Se3 nanosheet doped with Nd3+ ions via the two-step method of solid phase synthesis and liquid exfoliation. Owing to the special inner 4f-4f energy level transitions, lanthanide ions can emit photons with almost the same energy in different environments. Here, a stable near-infrared luminescence from Nd3+-doped 2D In2Se3 nanosheets has been realized, which includes emission bands around 910, 1057, and 1324 nm. The doping of Nd3+ ions extends the emission region of In2Se3 nanosheets. Moreover, the photoluminescence mechanism of Nd3+ ions was investigated through a series of optical measurements. This work not only provides a reliable method to fabricate lanthanide ion-doped 2D materials but also possesses a great significance for luminescence study of lanthanide ions in the 2D matrix

Advances, optical and electronic applications of functional materials based on rare earth sulfide semiconductors

Rare earth sulfides are a promising group of semiconductor materials with intricate crystal structures and unique electronic configurations, which can be applied in the fields of energy storage, environmental protection and inorganic pigments. In recent years, with the development of modulation tools, rare earth sulfides have gained attention in more fields, such as thermoelectric materials, magnetic materials and electrochemical detection. We need to better understand rare earth sulfides before we can develop practical functional materials. In this article, we present the basic crystal structures of rare earth sulfides with recent research progress in preparation methods and microstructure modulation. Combined with the work of our group, this article focuses on the breakthroughs of rare earth sulfides in applications such as inorganic pigments, energy materials and photocatalysis. Even more, we discuss the intrinsic link between structures and properties and the design strategies to enhance the optical, electronic and catalytic properties of rare earth sulfides. Finally, we summarize the challenges and future directions in the research of rare earth sulfides

Multi-Mode Lanthanide-Doped Ratiometric Luminescent Nanothermometer for Near-Infrared Imaging within Biological Windows

Owing to its high reliability and accuracy, the ratiometric luminescent thermometer can provide non-contact and fast temperature measurements. In particular, the nanomaterials doped with lanthanide ions can achieve multi-mode luminescence and temperature measurement by modifying the type of doped ions and excitation light source. The better penetration of the near-infrared (NIR) photons can assist bio-imaging and replace thermal vision cameras for photothermal imaging. In this work, we prepared core–shell cubic phase nanomaterials doped with lanthanide ions, with Ba2LuF7 doped with Er3+/Yb3+/Nd3+ as the core and Ba2LaF7 as the coating shell. The nanoparticles were designed according to the passivation layer to reduce the surface energy loss and enhance the emission intensity. Green upconversion luminescence can be observed under both 980 nm and 808 nm excitation. A single and strong emission band can be obtained under 980 nm excitation, while abundant and weak emission bands appear under 808 nm excitation. Meanwhile, multi-mode ratiometric optical thermometers were achieved by selecting different emission peaks in the NIR window under 808 nm excitation for non-contact temperature measurement at different tissue depths. The results suggest that our core–shell NIR nanoparticles can be used to assist bio-imaging and record temperature for biomedicine