Development of Highly Luminescent Water-Insoluble Carbon Dots by Using Calix[4]pyrrole as the Carbon Precursor and Their Potential Application in Organic Solar Cells

Abstract

Carbon dots (CDs) are carbon-based fluorescent nanomaterials that are of interest in different research areas due to their low cost production and low toxicity. Considering their unique photophysical properties, hydrophobic/amphiphilic CDs are powerful alternatives to metal-based quantum dots in LED and photovoltaic cell designs. On the other hand, CDs possess a considerably high amount of surface defects that give rise to two significant drawbacks: (1) causing decrease in quantum yield (QY), a crucial drawback that limits their utilization in LEDs, and (2) affecting the efficiency of charge transfer, a significant factor that limits the use of CDs in photovoltaic cells. In this study, we synthesized highly luminescent, water-insoluble, slightly amphiphilic CDs by using a macrocyclic compound, calix[4]pyrrole, for the first time in the literature. Calix[4]pyrrole-derived CDs (CP-DOTs) were highly luminescent with a QY of over 60% and size of around 4–10 nm with graphitic structure. The high quantum yield of CP-DOTs indicated that they had less amount of surface defects. Furthermore, CP-DOTs were used as an additive in the active layer of organic solar cells (OSC). The photovoltaic parameters of OSCs improved upon addition of CDs. Our results indicated that calix[4]pyrrole is an excellent carbon precursor to synthesize highly luminescent and water-insoluble carbon dots, and CDs derived from calix[4]pyrrole are excellent candidates to improve optoelectronic devices.

Doped Graphene Quantum Dots UV-Vis Absorption Spectrum: A high-throughput TDDFT study

“…Graphene is an excellent electron acceptor with mobility around 7 × 10 4 cm 2 • V −1 • s −1 and therefore has a great potential to improve efficiency of solar cells as a charge carrier [5]. GQDs, very small-sized graphene fragments whose bandgap can be controlled, are already in use for improving photovoltaic parameters of solar cells (photoconversion efficiency, the peak power, the short-circuit current density, the open circuit voltage and the fill factor) [5,6].…”

Aflatoxin B1 Acts as an Effective Energy Donor to Enhance Fluorescence of Yellow Emissive Carbon Dots

“…Both Ph:DOTs and U:PhDOTs displayed the same steady state optical properties (Figure ); each carbon dot possessed a single emission peak at 570 nm with a full width at half maxima (fwhm) of 85 nm. Also, absorption properties of quantum dots were very similar; the absorption spectrum of each carbon dot had a Gaussian peak at 440 nm, which corresponded to the band-edge transition, a rarely observed peak in absorption spectrum of carbon based quantum dots that could arise because of the formation of a rigid-crystal structure, and typical carbon dot absorption peaks at lower wavelengths (below 300 nm). On the other hand, the absorption peak of U:PhDOTs at 440 nm was slightly broader than that of PhDOTs in the wavelength range of 470–540 nm, which was an indication of the formation of new energy states due to surface modification.…”

“… 29 − 31 On the other hand, surface characteristics and composition of carbon dots can be manipulated through bottom-up synthesis relatively easily. 29 − 35 Among all types of bottom-up synthesis techniques, the microwave synthesis technique is one of the most preferred synthesis techniques to produce carbon dots with bright fluorescence, in other words, high quantum yield (QY) ( Figure 1 ). Blue-green emissive carbon dots with high quantum yield (above 25%) can be synthesized easily through microwave assisted synthesis techniques; however, there are only a few studies on the synthesis of yellow or red emissive carbon dots by using microwave assisted synthesis techniques.…”

“…Therefore, development of bright yellow and/or red emissive carbon dots is a hot topic and a challenge. The emission color of carbon dots can be controlled either by controlling the nanoparticle size or by controlling nanoparticle surface characteristics and composition. − The size control of carbon dots by using bottom-up synthesis methods can be challenging because of bottom-up synthesis conditions. − On the other hand, surface characteristics and composition of carbon dots can be manipulated through bottom-up synthesis relatively easily. − Among all types of bottom-up synthesis techniques, the microwave synthesis technique is one of the most preferred synthesis techniques to produce carbon dots with bright fluorescence, in other words, high quantum yield (QY) (Figure ). Blue-green emissive carbon dots with high quantum yield (above 25%) can be synthesized easily through microwave assisted synthesis techniques; however, there are only a few studies on the synthesis of yellow or red emissive carbon dots by using microwave assisted synthesis techniques. , Generally, isomers of phenylenediamine are the most preferred carbon precursors to synthesize yellow-red emissive carbon dots. ,, On the other hand, the highest quantum yield for yellow emissive carbon dots synthesized through microwave assisted synthesis methods was observed as 38.5% …”

Recent developments in calix[4]pyrrole (C4P)-based supramolecular functional systems

“…45 Conversely, from a biological viewpoint, besides acting as handy ion-transporters across the lipid bilayer membrane to treat defective ion channels, 46–48 C4P-based systems serve as drug carriers for the targeted defective tissues of the body, and also participate in pharmaceutical treatments in combating deadly diseases. 49,50 Moreover, these functional materials have also been exploited in the field of sensing for a wide range of anions, metal ions, and neutral molecules, 51–55 polymers, 56 catalysis, 57,58 polymorphism, 59 molecular machines, 60,61 molecular switches, 62–65 molecular probes, 66 metal ion coordination cages, 67 organic solar cells, 68 hydrogen sorption, 69 and adsorption of pollutants. 70,71 Additionally, they have also been utilized in the fabrication of stimuli-responsive materials, exhibiting enhanced non-linear optical/electronic properties, as revealed by theoretical and experimental studies.…”