Efficient Deep-Blue Light-Emitting Diodes from Highly Luminescent Eu2+-Doped Alkali Metal Halide Nanocrystals via Lattice Field Modulation.

Lead-halide perovskite nanocrystals (NCs) are promising for fabricating deep-blue (<460 nm) light-emitting diodes (LEDs), but their development is plagued by low electroluminescent performance and lead toxicity. Herein, the synthesis of 12 kinds of highly luminescent and eco-friendly deep-blue europium (Eu2+)-doped alkali-metal halides (AX:Eu2+; A = Na+, K+, Rb+, Cs+; X = Cl-, Br-, I-) NCs is reported. Through adjustment of the coordination environment, efficient deep-blue emission from Eu-5d → Eu-4f transitions is realized. The representative CsBr:Eu2+ NCs exhibit a high photoluminescence quantum yield of 91.1% at 441 nm with a color coordinate at (0.158, 0.023) matching with the Rec. 2020 blue specification. Electrically driven deep-blue LEDs from CsBr:Eu2+ NCs are demonstrated, achieving a record external quantum efficiency of 3.15% and half-lifetime of ∼1 h, surpassing the reported metal-halide deep-blue NCs-based LEDs. Importantly, large-area LEDs with an emitting area of 12.25 cm2 are realized with uniform emission, representing a milestone toward commercial display applications.

Highly efficient upconversion luminescence in narrow-bandgap Y2Mo4O15.

Lanthanide-doped upconversion (UC) materials have been extensively investigated for their unique capability to convert low-energy excitation into high-energy emission. Contrary to previous reports suggesting that efficient UC luminescence (UCL) is exclusively observed in materials with a wide bandgap, we have discovered in this study that Y2Mo4O15:Yb3+/Tm3+ microcrystals, a narrowband material, exhibit highly efficient UC emission. Remarkably, these microcrystals do not display any four- or five-photon UC emission bands. This particular optical phenomenon is independent of the variation in doping ion concentration, temperature, phonon energy, and excitation power density. Combining theoretical calculations and experimental results, we attribute the vanishing emission bands to the strong interaction between the bandgap of the Y2Mo4O15 host matrix (3.37 eV) and the high-energy levels (1I6 and 1D2) of Tm3+ ions. This interaction can effectively catalyze the UC emission process of Tm3+ ions, which leads to Y2Mo4O15:Yb3+/Tm3+ microcrystals possessing very strong UCL intensity. The brightness of these microcrystals outshines commercial UC NaYF4:Yb3+,Er3+ green phosphors by a factor of 10 and is 1.4 times greater than that of UC NaYF4:Yb3+,Tm3+ blue phosphors. Ultimately, Y2Mo4O15:Yb3+/Tm3+ microcrystals, with their distinctive optical characteristics, are being tailored for sophisticated anti-counterfeiting and information encryption applications.

Excitation power-dependent multicolor upconversion in NaLnF4:Er3+ under 1532†nm irradiation for anti-counterfeiting application.

Upconversion (UC) materials are renowned for their ability to convert low-energy photons into high-energy ones. The manipulation of parameters allows for the observation of multicolored UC luminescence (UCL) within a single material system. While modulation of multicolored UCL commonly relies on excitation at approximately 980 nm, investigation into multicolored UC materials activated by a 1532 nm excitation source remains comparatively scarce. In this work, we introduce NaLnF4:Er3+ as a novel class of smart luminescent materials. When the power density of a 1532 nm laser increases from 0.5 to 20.0 W/cm2, the emission peak positions remain unchanged, but the red-to-green (R/G) ratio decreases significantly from 18.82 to 1.48, inducing a color shift from red to yellow and ultimately to green. In contrast, no color variation is observed when NaLnF4:Er3+ is excited with a 980 nm laser at different power densities. This power-dependent multicolored UCL of NaLnF4:Er3+ excited at 1532 nm can be attributed to the competitive processes of upward pumping and downward relaxation of electrons on the 4I9/2 level of Er3+. By utilizing the unique UC characteristics of NaLnF4:Er3+, its potential utility in anti-counterfeiting applications is demonstrated. Our research highlights the distinctive optical properties of NaLnF4:Er3+ and provides novel insights into the use of luminescent materials in optical anti-counterfeiting technologies.

Double perovskite microcrystals-based white light-emitting diodes without reabsorption of multiphase phosphors.

Here, Tb3+ ions are incorporated into Cs2Ag0.6Na0.4InCl6:Bi double perovskite microcrystals via a re-crystallization method. Tb3+ ions doping not only makes the white light spectrum adjustable, but also maintains the high photoluminescence quantum yield (PLQY). The optimal value of PLQY is 95%. These are comparable to the current highest values. Noteworthy is that, intrinsic emission of Tb3+ ions is attributed to the effective energy transfer from the trapped exciton state of the double perovskite host to Tb3+ ions. Finally, mixing 30% Tb3+ alloyed Cs2Ag0.6Na0.4InCl6:Bi and Cs2NaInCl6:10%Sb phosphors, a series of double-perovskite-based white light-emitting diodes (WLEDs) are prepared. The color coordinates of the best WLEDs are (0.34, 0.32), the lumen efficiency is 42 lm/W, and the color rendering index is 94.3. It is worth mentioning here that there is no blue light loss caused by energy reabsorption between the two phosphors, because the excitation wavelengths of the two phosphors are concentrated in the ultraviolet band. This work provides a new strategy for preparing high-performance WLED.

Stable and Efficient Upconversion Single Red Emission from CsPbI3 Perovskite Quantum Dots Triggered by Upconversion Nanoparticles.

Here, composites including highly efficient inert shell-modified NaYF4:Yb/Tm@NaYF4 upconversion nanoparticles (UCNPs) and CsPbI3 perovskite quantum dots (PQDs) have been successfully synthesized by the assistance of (3-aminopropyl)triethoxysilane (APTES) as a precursor for a SiO2 matrix. UCNPs and CsPbI3 PQDs in this composite structure show excellent stability in ambient conditions. Importantly, the efficient UC emission of CsPbI3 PQDs was realized, which means that the single red emission of inert shell-modified UCNPs can be easily obtained by depending on these composite structures. Furthermore, the single red emission wavelength can be easily regulated from 705 to 625 nm by introducing appropriate proportion of Br- ions, which is very difficult to achieve for traditional UCNPs. Moreover, benefiting from the efficient downshifting (DS) red emission of CsPbI3 PQDs, the composites possess the dual-wavelength excitation characteristics. So, the excellent dual-mode anticounterfeiting application has been demonstrated. This work will provide a new idea for the development of perovskite-based multifunctional materials.

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.

Highly stable and water-soluble monodisperse CsPbX3/SiO2 nanocomposites for white-LED and cells imaging.

In spite of the excellent optical properties of all-inorganic halide perovskite quantum dots (PQDs), they still suffer from inherent poor stability even when exposed to moisture from the atmosphere, restricting their applications, especially in white-light-emitting diodes (LEDs) and cells imaging. Here, we proposed a strategy by encapsulating the CsPbX3 (X = Cl, Br, I) PQDs into silica nanoplates to prepare highly stable and water-soluble CsPbX3/SiO2 nanocomposites. First, the 120 nm monodisperse CsPbX3/SiO2 nanocomposites inlayed with several CsPbX3 PQDs were fabricated via the modified Stöber method. After coating, their stability exposed in the air was largely improved for all the CsPbX3 (X = Cl, Br, I) PQDs without changing their emission peaks and full-width at half-maximum, attributed to the suppression of the anion-exchange and decomposition. Moreover, further experiments demonstrated that the CsPbX3/SiO2 nanocomposites were highly water-soluble and stable in the water. Their applications in LEDs and cell imaging demonstrated their ultrastability and high biocompatibility. Therefore, this study shows the possibility of their use in photoelectric devices and biological applications.

Highly efficient and stable blue-emitting CsPbBr3@SiO2 nanospheres through low temperature synthesis for nanoprinting and WLED.

Inorganic perovskite quantum dots (QDs) have attracted wide attention in display and solid-state lighting because of their easily tunable band-gaps and high photoluminescence quantum yields (PLQY) of green light emission. However, some drawbacks limit their practical applications, including the low PLQY of blue light emission and the instability in the moisture environment. In this work, efficient blue-light emitting CsPbBr3 perovskite QDs with PLQY of 72% were developed through a bandgap engineering approach. The achieved blue-light emitting PLQY is much higher than the values acquired in the inorganic perovskite QDs in the literature. And the emission color of the as-prepared QDs can be facially tuned by only adjusting the reaction temperature. Further, the mono-dispersed perovskite QDs@SiO2 composites were constructed benefiting from the low temperature synthesis. The optical performance of the QDs could be well persisted even in the moisture environment. Finally, the as-prepared QDs@SiO2 composite was fabricated as the QD ink on the anti-counterfeit printing technology, from which the obtained pattern would emit varied color under UV lamp. And the as-prepared composites was also applied for fabricating WLED, with Commission Internationale de l'Eclairage (CIE) color coordinates of (0.33, 0.38) and power efficiency of 32.5 lm W-1, demonstrating their promising potentials in solid-state lighting.

Emitting color tunable carbon dots by adjusting solvent towards light-emitting devices.

Carbon dots (CDs), one of the most significant classes of carbon-based nanophosphors, have attracted extensive attention in recent years. However, few attempts have been reported for realizing CDs with tunable emissions, especially for obtaining the red-light emissions with high photoluminescence quantum yields. Herein, we synthesized CDs with different chromatic blue, green and red emissions by facilely changing the reaction solvent during hydrothermal conditions. The photoluminescence quantum yields of 34%, 19% and 47% for the blue, green and red emissions, respectively, were achieved. Furthermore, the solid-state CD/PVA composite films were constructed through mixing the CDs with PVA polymer, in which the self-quenching of photoluminescence of CDs had been successfully avoided benefiting from the formation of hydrogen bonds between the CDs and PVA molecules. Finally, the warm white light emitting diode (WLED) was fabricated by integrating CD/PVA film on a UV-LED chip. The WLED exhibited the Commission International de l'Eclairage coordinates (CIE) of (0.38, 0.34), correlated color temperature of 3913 K and color rendering index of 91, respectively, which were comparable with the commercial WLEDs.

Modulation of the photoluminescence in carbon dots through surface modification: from mechanism to white light-emitting diodes.

Carbon dots (CDs) have emerged as a new type of fluorescent material because of their unique optical advantages, such as high photoluminescence quantum yields (QYs), excellent photo-stability, excitation-dependent emissions, and low toxicity. However, the photoluminescence mechanism for CDs remains unclear, which limits their further practical application. Here, CDs were synthesized via a solvothermal route from citric acid and urea. Through the oxidation and reduction treatment of pristine CDs, the origin of the photoluminescence and the involved mechanism were revealed. We found that the blue/green/red emissions originated from three diverse emitting states, i.e. the intrinsic state, and C=O- and C=N-related surface states, respectively. Based on the as-prepared CDs, a pH sensor depending on the radiometric luminescence detection was developed. Furthermore, we constructed CD/PVP (PVP, polyvinylpyrrolidone) composite films, which exhibited white light emission with photoluminescence QYs of 15.3%. The white light emission with different correlated color temperatures (CCTs), from 4807 K to 3319 K, was obtained by simply changing the amount of PVP solution. Benefiting from the white light-emitting solid-state films, single-component white light-emitting diodes were fabricated with an average color rendering index value (Ra) of 80.0, luminous efficiency of 10.2 lm W-1, and good working stability, thus indicating a promising potential for practical lighting applications.

Carbon dot/polyvinylpyrrolidone hybrid nanofibers with efficient solid-state photoluminescence constructed using an electrospinning technique.

Carbon dots (CDs) are the promising candidates for application in optoelectronic and biological areas due to their excellent photostability, unique photoluminescence, good biocompatibility, low toxicity and chemical inertness. However, the self-quenching of photoluminescence as they are dried into the solid state dramatically limits their further application. Therefore, realizing efficient photoluminescence and large-scale production of CDs in the solid state is an urgent challenge. Herein, solid-state hybrid nanofibers based on CDs and polyvinylpyrrolidone (PVP) are constructed through an electrospinning process. The resulting solid-state hybrid PVP/CD nanofibers present much enhanced photoluminescence performance compared to the corresponding pristine colloidal CDs due to the decrease in non-radiative recombination of electron-holes. Owing to the suppressed self-quenching of CDs, the photoluminescence quantum yield is considerably improved from 42.9% of pristine CDs to 83.5% of nanofibers under the excitation wavelength of 360 nm. This has great application potential in optical or optoelectronic devices.

Doping Lanthanide into Perovskite Nanocrystals: Highly Improved and Expanded Optical Properties.

Cesium lead halide (CsPbX3) perovskite nanocrystals (NCs) have demonstrated extremely excellent optical properties and great application potentials in various optoelectronic devices. However, because of the anion exchange, it is difficult to achieve white-light and multicolor emission for practical applications. Herein, we present the successful doping of various lanthanide ions (Ce3+, Sm3+, Eu3+, Tb3+, Dy3+, Er3+, and Yb3+) into the lattices of CsPbCl3 perovskite NCs through a modified hot-injection method. For the lanthanide ions doped perovskite NCs, high photoluminescence quantum yield (QY) and stable and widely tunable multicolor emissions spanning from visible to near-infrared (NIR) regions are successfully obtained. This work indicates that the doped perovskite NCs will inherit most of the unique optical properties of lanthanide ions and deliver them to the perovskite NC host, thus endowing the family of perovskite materials with excellent optical, electric, or magnetic properties.

Ultraviolet-Visible-Near-Infrared Broadband Photodetector Enabled by Cs2AgBiBr6: Sn/Conjugated Polymer Heterojunction.

Broadband photodetectors covering ultraviolet (UV) to near-infrared (NIR) wavelengths play an essential role in communications, imaging, and biosensing. Developing a single photodetector with a broadband optical response operating at room temperature can significantly reduce the complexity and cost of receiver systems for multispectral applications. In this work, utilizing the porous structure characteristics of Cs2AgBiBr6:Sn thin films, a self-powered detector with broad spectral response (UV-vis-NIR) was achieved by constructing an effective Cs2AgBiBr6:Sn/PDPP3T heterojunction. This photodetector possesses a broad response spectrum from 350 to 950 nm with an average detection rate exceeding 1011 Jones and maintains excellent photoelectric performance over two months. Sn2+ doping effectively reduces the bandgap of Cs2AgBiBr6, enhancing its near-infrared absorption and optimizing energy level alignment with conjugated polymer (diketopyrrolopyrrole-terthiophene, PDPP3T). More importantly, the porous structure derived from Sn doping significantly improves carrier extraction and transport under a near-infrared light response at the heterojunction interface. Utilizing its broad spectral response characteristics in the UV-vis-NIR range, a novel information transfer and encryption system employing full optical modulation has been realized within a single perovskite photodetector. This work provides a new approach to fabricating lead-free double perovskite broadband photodetectors with potential applications in photonic devices.

Hyper-branched CdTe nanostructures based on the self-assembling of quantum dots and their optical properties.

As the priority of interconnects and active components in nanoscale optical and electronic devices, three-dimensional hyper-branched nanostructures came into focus of research. Recently, a novel crystallization route, named as "nonclassical crystallization," has been reported for three-dimensional nanostructuring. In this process, Quantum dots are used as building blocks for the construction of the whole hyper-branched structures instead of ions or single-molecules in conventional crystallization. The specialty of these nanostructures is the inheritability of pristine quantum dots' physical integrity because of their polycrystalline structures, such as quantum confinement effect and thus the luminescence. Moreover, since a longer diffusion length could exist in polycrystalline nanostructures due to the dramatically decreased distance between pristine quantum dots, the exciton-exciton interaction would be different with well dispersed quantum dots and single crystal nanostructures. This may be a benefit for electron transport in solar cell application. Therefore, it is very necessary to investigate the exciton-exciton interaction in such kind of polycrystalline nanostructures and their optical properites for solar cell application. In this research, we report a novel CdTe hyper-branched nanostructures based on self-assembly of CdTe quantum dots. Each branch shows polycrystalline with pristine quantum dots as the building units. Both steady state and time-resolved spectroscopy were performed to investigate the properties of carrier transport. Steady state optical properties of pristine quantum dots are well inherited by formed structures. While a suppressed multi-exciton recombination rate was observed. This result supports the percolation of carriers through the branches' network.

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.

Highly efficient and stable red perovskite quantum dots through encapsulation and sensitization of porous CaF2:Ce,Tb nanoarchitectures.

Lead halide perovskite quantum dots (PQDs) are extremely unstable when exposed to oxygen, water and heat, especially red CsPbBrxI3-x (x = 0, 0.5, 1.2) PQDs. This seriously hinders their practical application. Here, red CsPbBrxI3-x (x = 0, 0.5, 1.2) PQDs have been successfully encapsulated in porous CaF2:Ce,Tb hierarchical nanospheres (HNSs), which not only greatly improved the stability of PQDs, benefitting from the protection of the CaF2 shell, but also maintained the high photoluminescence quantum yield (PLQY) of PQDs, benefitting from the sensitization of Tb3+ ions. More importantly, porous CaF2:Ce,Tb nanoarchitectures can prevent aggregation quenching and anion exchange of PQDs. Therefore, the CaF2:Ce,Tb&CsPbBrxI3-x (x = 0, 0.5, 1.2) composite powder can have high PLQY comparable to that of the PQD powder. In view of this, CaF2:Ce,Tb&CsPbBr1.2I1.8 composite based red light-emitting diodes (LEDs) are prepared, and they are very suitable as a supplementary light source for plant lighting. Furthermore, white LEDs are also prepared by coating the CaF2:Ce,Tb&CsPbBr3 and CaF2:Ce,Tb&CsPbBr1.2I1.8 composite on a 450 nm chip. The optimum luminous efficiency is 61.2 lm W-1, and the color rendering index is 91, which are comparable to the current highest values. This shows that the composite composed of PQDs has great potential in LED lighting.

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.

Hyperbranched CdTe nanostructures via a self-assembly route: optical properties.

In this work, we report a luminescent nanobundle structure formed by a hierarchical self-assembly process of thioglycolic acid (TGA)-capped CdTe quantum dots (QDs). The luminescence intensity of CdTe nanostructures is high enough to get a clear one-photon excitation confocal image. High contrast two-photon excitation confocal images suggest that the nonlinear properties of pristine QDs are well inherited by the formed CdTe nanostructures. The controllability of the structures and inheritance of the optical properties of the building units make the self-assembled nanostructures new generation materials.

High-Performance Perovskite Solar Cells Based on NaCsWO3@ NaYF4@NaYF4:Yb,Er Upconversion Nanoparticles.

Extending photoelectric response to the near-infrared (NIR) region using upconversion luminescent (UCL) materials is one promising approach to obtain high-efficiency perovskite solar cells (PSCs). However, challenges remain due to the shortage of highly efficient UCL materials and device structure. NaCsWO3 nanocrystals exhibit near-infrared absorption arising from the local surface plasmon resonance (LSPR) effect, which can be used to boost the UCL of rare-earth-doped upconversion nanoparticles (UCNPs). In this study, using NaCsWO3 as the LSPR center, NaCsWO3@NaYF4@NaYF4:Yb,Er nanoparticles were synthesized and the UCL intensity could be enhanced by more than 124 times when the amount of NaCsWO3 was 2.8 mmol %. Then, such efficient UCNPs were not only doped into the hole transport layer but also used to modify the perovskite film in PSCs, resulting in the highest power conversion efficiency (PCE) reaching 18.89% (that of the control device was 16.01% and the PCE improvement was 17.99%). Possible factors for the improvement of PSCs were studied and analyzed. It is found that UCNPs can broaden the response range of PSCs to the NIR region due to the LSPR-enhanced UCL and increase the visible light reabsorption of PSCs due to the scattering and reflection effect, which generate more photocurrent in PSCs. In addition, UCNPs modify the perovskite film by effectively filling the holes and gaps at the grain boundary and eliminating the perovskite surface defects, which lead to less carrier recombination and then effectively improve the performance of PSC devices.

Ni2+ and Pr3+ Co-doped CsPbCl3 perovskite quantum dots with efficient infrared emission at 1300 nm.

Lead halide perovskite quantum dots (PQDs) show great prospects in the field of optoelectronic applications. Although having high efficiency and narrow-band emission performance in the visible light region, the infrared multicolor luminescence performance of perovskite nanocrystals is still highly desired. In this work, in order to increase the luminescence intensity and extend the infrared multicolor luminescence, transition metal and rare earth ions are co-doped into PQDs. Herein, PQDs emitting at 1300 nm are realized by Pr3+ doping, which has not been reported in previous literature. The luminescence and kinetic process of Ni2+ and Pr3+ co-doped CsPbCl3 PQDs are studied, which exhibit considerably enhanced emission intensity at 400 nm and 1300 nm, with an overall quantum efficiency of photoluminescence (PLQY) of 89% and the highest infrared PLQY of 23%.