Supplementary document for Lifetime-tunable Green Room Temperature Phosphorescence of Carbon Dots by the Multi-step Modification - 5355930.pdf

Fig S1-S7 and Table S

Supplementary document for Highly efficient upconversion luminescence in narrow-bandgap Y2Mo4O15 - 6932633.pdf

Supplemental Documen

High-Efficiency and Wavelength-Tunable Near-Infrared Emission of Lanthanide Ions Doped Lead-Free Halide Double Perovskite Nanocrystals toward Fluorescence Imaging

Near-infrared (NIR) fluorescent materials show unique photophysical properties, which make them widely used in optical communication, night vision imaging, biomedicine, and other applications. However, the development of high-efficiency and wavelength-tunable NIR nanomaterials is still a challenge. Herein, a series of lanthanide ions doped Cs2AgIn0.99Bi0.01Cl6 double perovskite nanocrystals (DPNCs) with wavelength-tunable NIR light emission (800–1600 nm) have been synthesized. The optimal photoluminescence quantum yield (PLQY) of the DPNCs reaches 66.7%, which is a record value for DPNCs. It is mainly attributed to the contribution of NIR emission of lanthanide ions doped into DPNCs. More importantly, the series of NIR emission wavelengths of lanthanide ions doped Cs2AgIn0.99Bi0.01Cl6 DPNCs include not only shorter-wavelength NIR light (≤900 nm) but also longer-wavelength NIR light (>900 nm), which are more appropriate for foodstuff analysis and medical diagnosis applications. Furthermore, 11.2% Nd3+ doped Cs2AgIn0.99Bi0.01Cl6 DPNCs with the optimal PLQY were embedded in a polymethyl methacrylate (PMMA) polymer matrix (DPNCs@PMMA), and the stability of DPNCs modified by PMMA has been greatly improved. Finally, the 11.2% Nd3+ ions doped Cs2AgIn0.99Bi0.01Cl6 DPNCs@PMMA based NIR LEDs have demonstrated good night vision and human tissue penetration. This work indicates that lanthanide ions doped DPNCs have a potential in NIR light applications and could inspire future research to explore novel lanthanide ions doped semiconductor NCs based NIR LEDs

High-Performance Sn-Based Quasi-Two-Dimensional Perovskite Photodetectors by Altering Dark Current Shunt Pathways

Self-powered perovskite photodetectors (PDs) have been widely used in the fields of communications and imaging, but their performance is still restricted by the high dark current of devices. This study has shown that the dark current of PDs can be significantly reduced by adjusting the composition of the dark current shunting paths. We have fabricated a less toxic high-performance PDs based on two-dimensional tin-based perovskite BA2FASn2I7. By controlling the grain size of the perovskite film with potassium salt of hydroquinone sulfonic acid (KHQSA), we increased the number of horizontal shunting paths and the dark current was reduced to 1/50th of its original value. The device shows a high responsivity of 1.4 A W–1, a high detectivity of 8.2 × 1013 Jones, a maximum on/off current ratio of 6.74 × 105, and a rapid rise/decay time of 12.2/14 ms. In addition, as a light signal receiver in an imaging system, the device can accurately and sensitively identify light signals under weak light conditions. This study provides a new way for further improving the performance of self-powered perovskite PDs by adjusting the composition of horizontal and vertical dark current shunting paths

Impact of Host Composition, Codoping, or Tridoping on Quantum-Cutting Emission of Ytterbium in Halide Perovskite Quantum Dots and Solar Cell Applications

Recently, various lanthanide ions (Ln3+) have been successfully doped into perovskite quantum dots (PQDs), and the quantum-cutting emission of 2F5/2–2F7/2 for Yb3+with a measurable inner efficiency of more than 100% has been discovered and applied as the luminescent converter of solar cells, which has opened a new branch for the application of PQDs. In this work, to further improve the quantum-cutting efficiency of Yb3+, the codoping and tridoping methods were used to improve the quantum-cutting emission of PQDs. The Yb3+–Ln3+ (Ln = Nd, Dy, Tb, Pr, Ce) pair-doped CsPbClxBryI3–x–y PQDs were fabricated, with all displaying excitonic emission, narrow-band emission of Ln3+ ions, and quantum-cutting emission of Yb3+ ions. It was interesting that Yb3+–Pr3+ as well as Yb3+–Ce3+ pairs could effectively sensitize the emission of Yb3+, owing to Pr3+ and Ce3+ ions offering intermediate energy states close to the exciton transition energy of the PQDs. After host composition optimization and tridoping investigation, overall emissions with a 173% photoluminescence quantum yield (PLQY) were obtained in the Yb3+–Pr3+–Ce3+-tridoped CsPbClBr2 PQDs. Then, the tridoped PQDs were designed as the down-converter for CuIn1–xGaxSe2 (CIGS) as well as the silicon solar cells, which leads to an enhancement of the power conversion efficiency (PCE) of as high as ∼20%. The modified CIGS was further employed to charge the smart mobile phone, which could largely shorten the charging time from 180 to 150 min. This finding is of great significant for expanding the application fields of the impurity-doped PQDs

Supplementary document for Double perovskite microcrystals based white light-emitting diodes without reabsorption of multiphase phosphors - 5541184.pdf

Supplemental Document

Tunable and Efficient Photoluminescence of Lanthanide-Doped Cs₂NaScCl₆ Double Perovskite Single Crystals toward Multifunctional Light-Emitting Diode Applications

Lead-free halide double perovskite, as one of the promising candidates for lead halide perovskite materials, shows great potential in light-emitting diodes (LEDs), benefiting from its environmental friendliness and high chemical stability. However, the poor regulation of the emission spectra severely limits its application range. Herein, various lanthanide ions were successfully doped in Cs2NaScCl6 double perovskite single crystals (DPSCs) to yield effective and stable emissions spanning from visible to near-infrared (NIR) regions. Notably, efficient energy transfer from the host to the dopants enables tunable emissions with good chromaticity, which is rarely reported in the field of lead-free double perovskite. Moreover, density functional theory calculations reveal that the high local electron density around the [LnCl6]3– octahedron in DPSCs plays a key role in the improvement of photoluminescence quantum yields (PLQYs). The optimal PLQYs are up to 84%, which increases around 3 times over that of the undoped sample. Finally, multicolor and NIR LEDs based on Ln3+-doped Cs2NaScCl6 DPSCs were fabricated and had different application functions. Specifically, the single-composite white LED shows adjustable coordinates and correlated color temperatures, while the NIR LED shows good night vision imaging. This work provides new inspiration for the application of efficient multifunctional LEDs based on lead-free double perovskite materials

Europium-Doped Lead-Free Cs₃Bi₂Br₉ Perovskite Quantum Dots and Ultrasensitive Cu²⁺ Detection

Pollution triggered by highly toxic heavy metal ions has become of worldwide critical concern; thus, it is urgent to develop an eco-friendly and nontoxic fluorescence probe for metal ions sensing. The lead-free all-inorganic perovskite quantum dots (PeQDs) could be ideal candidates but are limited by their low photoluminescence quantum yield (PLQY). In this work, we successfully fabricated Eu3+-doped lead-free Cs3Bi2Br9 PeQDs employing a modified ligand-assisted reprecipitation method. The Cs3Bi2Br9:Eu3+ PeQDs demonstrate multicolor emissions including the exciton emission of the PeQDs and the5D0–7FJ transition for Eu3+ ion. Compared to the bare Cs3Bi2Br9 PeQDs, the Eu3+-doped PeQDs display highly improved PLQY from 18% to ∼42.4% and excellent water stability. Finally, nontoxic and highly efficient Cs3Bi2Br9:Eu3+ PeQDs were employed as a highly sensitive fluorescent probe for Cu2+ ion detection in water, which demonstrates a good linear range from 5 nM to 3 μM with a correlation coefficient of 0.996 and a low detection limit of 10 nM. Our work not only provides a new strategy to improve the optical performance of lead-free PeQDs but also expands their applications for metal ions sensing