scholarly journals A Mini Review on pH-Sensitive Photoluminescence in Carbon Nanodots

2021 ◽  
Vol 8 ◽  
Author(s):  
Cui Liu ◽  
Fang Zhang ◽  
Jiao Hu ◽  
Wenhui Gao ◽  
Mingzhen Zhang
Keyword(s):  
Optical Properties ◽  
Low Cost ◽  
Ph Sensitive ◽  
Research Progress ◽  
Future Research ◽  
Carbon Nanodots ◽  
Ph Sensing ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Wide Range

Carbon nanodots (C-dots) with sp2/sp3 framework and diameter of <10 nm contain abundant functional groups or polymers on their surface. C-dots have attracted immense attention because of their unique optical properties, excellent biocompatibility, facile preparation, and low cost. With these merits, C-dots have been used in a wide range of applications including sensing, bioimaging, catalysis, and light-emitting devices. C-dots exhibit good optical properties, such as tunable emission wavelength, good photostability, nonblinking, up-conversion emission, etc. Of note, C-dots show intrinsic pH-sensitive photoluminescence (PL), indicating their great potential for pH sensing, especially in biotic pH sensing. In this review, we systematically summarize the pH-sensitive PL properties and the pH-sensitive PL mechanism, as well as recent research progress of C-dots in pH sensing. The current challenges of pH-sensitive C-dots and their future research focus are also proposed here. We anticipate this review might be of great significance for understanding the characteristics of pH-sensitive C-dots and the development of photoluminescent nanomaterials with pH-sensitive properties.

Tuning optical properties of CsPbBr3 by mixing Nd3+trivalent lanthanide halide cations for blue light emitting devices.

2022 ◽  
Author(s):  
Muhammad Amin Padhiar ◽  
Minqiang Wang ◽  
Yongqiang Ji ◽  
Zhi Yang ◽  
Arshad Saleem Bhatti
Keyword(s):  
Optical Properties ◽  
Blue Light ◽  
Light Emission ◽  
Low Cost ◽  
Thermal Quenching ◽  
Visible Spectrum ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Lanthanide Halide ◽  
Trivalent Lanthanide

Abstract In recent years, significant progress has been made in the red and green perovskite quantum dots (PQDs) based light-emitting devices. However, a scarcity of blue-emitting devices that are extremely efficient precludes their research and development for optoelectronic applications. Taking advantage of tunable bandgaps of PQDs over the entire visible spectrum, herein we tune optical properties of CSPbBr3 by mixing Nd3+ trivalent lanthanide halide cations for blue light-emitting devices. The CsPbBr3 PQDs doped with Nd3+ trivalent lanthanide halide cations emitted strong photoemission from green into the blue region. By adjusting their doping concentration, a tunable wavelength from (515 nm) to (450 nm) was achieved with FWHM from (37.83 nm) to (16.6 nm). We simultaneously observed PL linewidth broadening thermal quenching of PL and the blue shift of the optical bandgap from temperature-dependent PL studies. The Nd3+ cations into CsPbBr3 PQDs more efficiently reduced non-radiative recombination. As a result of the efficient removal of defects from PQDs, the photoluminescence quantum yield (PLQY) has been significantly increased to 91% in the blue-emitting region. Significantly, Nd3+ PQDs exhibit excellent long-term stability against the external environment, including water, temperature, and ultraviolet light irradiation. Moreover, we successfully transformed Nd3+ doped PQDs into highly fluorescent nanocomposites. Incorporating these findings, we fabricate and test a stable blue light-emitting LED with EL emission at (462 nm), (475 nm), and successfully produce white light emission from Nd3+ doped nanocomposites with a CIE at (0.32, 0.34), respectively. The findings imply that low-cost Nd3+ doped perovskites may be attractive as light converters in LCDs with a broad color gamut.

scholarly journals Fluorescent Carbon Nanodots as Sensors of Toxic Metal Ions and Pesticides

2021 ◽  
Vol 6 (1) ◽  
pp. 21
Author(s):  
Federico Bruno ◽  
Alice Sciortino ◽  
Gianpiero Buscarino ◽  
Marco Cannas ◽  
Franco Mario Gelardi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Low Cost ◽  
Synthesis Method ◽  
Toxic Metal ◽  
Size Exclusion ◽  
Carbon Nanodots ◽  
Molar Ratios ◽  
Wide Range ◽  
Fluorescent Carbon

Carbon nanodots (CDs) are a new class of fluorescent carbon-based nanomaterials characterized by a plethora of morphologies and sizes. Among these, we can include two different types of CDs, namely, graphitic and diamond-like. This wide range of structures opens up the possibility to design different CDs, with tunable optical properties accordingly to the synthesis method and precursors used. We prepared two different CDs following a bottom-up approach by thermally induced decomposition of organic precursors (namely, citric acid and urea in different molar ratios), and using purification by Size Exclusion Chromatography (SEC). Obtained CDs were characterized by Raman, absorption and fluorescence (PL) spectroscopies to understand structural and optical properties, and by atomic force microscopy (AFM) to elucidate morphology. They feature graphitic and diamond-like carbon structures with highly efficient visible emissions. Their sensing towards Cd and Hg heavy metals has been tested by PL experiments. We found a PL quenching in the presence of concentrations of metal salts starting from 0.5 μM and a selectivity towards the interacting ions, depending on the CDs structure, enabling using them for sensing. Furthermore, preliminary experiments suggest that these dots can also be used in principle as sensors of common pesticides. Considering the advantages of carbon dots with respect to other nanomaterials, such as non-toxicity, low cost and ease of synthesis, we consider these results to be very promising in view of exploiting the optical response of carbon dots to fabricate in the near future a variety of pollutant-sensing devices.

One-pot synthesis of double silane-functionalized carbon dots with tunable emission and excellent coating properties for WLEDs application

2021 ◽  
Author(s):  
Wenbing Cao ◽  
Yuhan Wu ◽  
Xin Li ◽  
Xuanfeng Jiang ◽  
Yuhong Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Great Influence ◽  
Alkoxy Group ◽  
Color Temperature ◽  
Molar Ratio ◽  
Coating Properties ◽  
One Pot ◽  
Light Emitting ◽  
Light Emitting Devices

Abstract Silane-functionalized carbon dots (SiCDs) can be exploited as effective color converting materials for the solid-state light-emitting devices. However, most of SiCDs reported thus far have shown photoluminescence emissions in the blue and green spectral range, which limit them to construct an efficient white light-emitting diodes (WLEDs) due to the lack of long-wavelength emission. Herein, a series of double silane-functionalized carbon dots (DSiCDs) were prepared via a one-step solvothermal method. The results show that the organic functional group of the silane has great influence on the optical properties of DSiCDs and the number of alkoxy group in the silane has great influence on coating properties of DSiCDs. In addition, the DSiCDs prepared by (3-aminopropyl)triethoxysilane and N-[3-(Trimethoxysilyl)propyl]ethylenediamine with molar ratio of 7:3 show excellent optical properties with the maximum emission at 608 nm under 400 nm excitation. Furthermore, they can be completely dried within 1 h at room temperature to form fluorescent coating with high stability and strong adhesion to the substrate. Together with their excellent optical and coating properties, they can be directly coated on LED chips to prepare WLEDs, with a CIE coordinate of (0.33,0.31), color rendering index of 81.6, and color temperature of 5774 K.

Research progress of quantum dot light-emitting devices for display application

2021 ◽  
Vol 36 (1) ◽  
pp. 176-186
Author(s):  
Xiao-ya GUAN ◽  
◽  
Hong-zhe WANG ◽  
Huai-bin SHEN ◽  
Zu-liang DU
Keyword(s):  
Quantum Dot ◽  
Research Progress ◽  
Light Emitting ◽  
Light Emitting Devices

scholarly journals Widely applicable phosphomolybdic acid doped poly(9-vinylcarbazole) hole transport layer for perovskite light-emitting devices

RSC Advances ◽  
2019 ◽  
Vol 9 (52) ◽  
pp. 30398-30405
Author(s):  
Yanting Wu ◽  
Zewu Xiao ◽  
Lihong He ◽  
Xiaoli Yang ◽  
Yajun Lian ◽  
...  
Keyword(s):  
Phosphomolybdic Acid ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Injection ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Wide Range ◽  
Selection Of ◽  
Range Selection

Perovskite light-emitting devices using a PVK:PMA hole transport layer show robust performance, allowing the wide range selection of antisolvents and hole injection layers.

scholarly journals The dark exciton ground state promotes photon-pair emission in individual perovskite nanocrystals

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Philippe Tamarat ◽  
Lei Hou ◽  
Jean-Baptiste Trebbia ◽  
Abhishek Swarnkar ◽  
Louis Biadala ◽  
...  
Keyword(s):  
Near Infrared ◽  
Exciton State ◽  
Lead Iodide ◽  
Electron Hole ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Light Emitting Devices ◽  
Optical And Electronic Properties ◽  
Wide Range ◽  
Halide Perovskites

AbstractCesium lead halide perovskites exhibit outstanding optical and electronic properties for a wide range of applications in optoelectronics and for light-emitting devices. Yet, the physics of the band-edge exciton, whose recombination is at the origin of the photoluminescence, is not elucidated. Here, we unveil the exciton fine structure of individual cesium lead iodide perovskite nanocrystals and demonstrate that it is governed by the electron-hole exchange interaction and nanocrystal shape anisotropy. The lowest-energy exciton state is a long-lived dark singlet state, which promotes the creation of biexcitons at low temperatures and thus correlated photon pairs. These bright quantum emitters in the near-infrared have a photon statistics that can readily be tuned from bunching to antibunching, using magnetic or thermal coupling between dark and bright exciton sublevels.

Sign in / Sign up

Export Citation Format

Share Document