Wide-bandgap organic solar cells with a novel perylene-based non-fullerene acceptor enabling open-circuit voltages beyond 1.4 V.

A perylene-based acceptor (PMI-FF-PMI), consisting of two perylene monoimide (PMI) units bridged with a dihydroindeno[1,2 b]fluorene molecule was developed as a potential non-fullerene acceptor (NFA) for organic solar cells (OSCs)....

Studies on the Performance of Two Dimensional AlSi as the Anodes of Li Ion Battery

Recently, two-dimensional (2D) materials have been rapidly developed and they provided a wide application on the anode of the batteries, reducing the adverse effect of traditional ion batteries including low capacity, short cycle life, low charging rate and poor safety mainly coming from the use of graphite anode. The current report investigates the anode performances of AlSi, a new 2D material exfoliated from NaAlSi, for Li ion batterys (LIBs) through density functional theory (DFT) calculations and gives quantitative discussions on the Li ion valences, binding energies and open-circuit voltages of 2D AlSi anode. The results indicate that 2D AlSi performs great as a novel anode due to the moderate adhesion to Li and low barrier for ion diffusion. Furthermore, our research results illustrate a broad application prospect on the new anode inventions as well as reducing useless consumption on the batteries by the practice of AlSi anode.

Remarkable Ionic Conductivity in a LZO-SDC Composite for Low-Temperature Solid Oxide Fuel Cells

Recently, appreciable ionic conduction has been frequently observed in multifunctional semiconductors, pointing out an unconventional way to develop electrolytes for solid oxide fuel cells (SOFCs). Among them, ZnO and Li-doped ZnO (LZO) have shown great potential. In this study, to further improve the electrolyte capability of LZO, a typical ionic conductor Sm0.2Ce0.8O1.9 (SDC) is introduced to form semiconductor-ionic composites with LZO. The designed LZO-SDC composites with various mass ratios are successfully demonstrated in SOFCs at low operating temperatures, exhibiting a peak power density of 713 mW cm−2 and high open circuit voltages (OCVs) of 1.04 V at 550 °C by the best-performing sample 5LZO-5SDC, which is superior to that of simplex LZO electrolyte SOFC. Our electrochemical and electrical analysis reveals that the composite samples have attained enhanced ionic conduction as compared to pure LZO and SDC, reaching a remarkable ionic conductivity of 0.16 S cm−1 at 550 °C, and shows hybrid H+/O2− conducting capability with predominant H+ conduction. Further investigation in terms of interface inspection manifests that oxygen vacancies are enriched at the hetero-interface between LZO and SDC, which gives rise to the high ionic conductivity of 5LZO-5SDC. Our study thus suggests the tremendous potentials of semiconductor ionic materials and indicates an effective way to develop fast ionic transport in electrolytes for low-temperature SOFCs.

Comparative Studies on Monolayer and Bilayer Phosphorous as the Anodes of Li Ion Battery

Recently, two-dimensional (2D) material developed rapidly and provided a wide application on the anode of the batteries, reducing the adverse effect of traditional ion batteries such as low capacity, short cycle life, slow charging and poor safety mainly coming from the use of graphite anode. The current report investigates the anode performances of phosphorus, a new 2D material in electrochemistry field, with monolayer and bilayer structure for Li ion batterys (LIBs) through density functional theory (DFT) calculations and gives a comparison on the Li ion valences, binding energies and open-circuit voltages between the two structures. The results indicate that bilayer phosphorus perform better as a novel anode due to the stronger adhesion to Li and lower barrier for ion diffusion. Furthermore, our research results illustrate a broad application prospect on the new anode inventions as well as reducing useless consumption on the batteries by the practice of bilayer phosphorus anode.

Variance-resistant PTB7 and axially-substituted silicon phthalocyanines as active materials for high-Voc organic photovoltaics

While the efficiency of organic photovoltaics (OPVs) has improved drastically in the past decade, such devices rely on exorbitantly expensive materials that are unfeasible for commercial applications. Moreover, examples of high voltage single-junction devices, which are necessary for several applications, particularly low-power electronics and rechargeable batteries, are lacking in literature. Alternatively, silicon phthalocyanines (R2-SiPc) are inexpensive, industrially scalable organic semiconductors, having a minimal synthetic complexity (SC) index, and are capable of producing high voltages when used as acceptors in OPVs. In the present work, we have developed high voltage OPVs composed of poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno [3,4 b]thiophenediyl}) (PTB7) and an SiPc derivative ((3BS)2-SiPc). While changes to the solvent system had a strong effect on performance, interestingly, the PTB7:(3BS)2-SiPc active layer were robust to spin speed, annealing and components ratio. This invariance is a desirable characteristic for industrial production. All PTB7:(3BS)2-SiPc devices produced high open circuit voltages between 1.0 and 1.07 V, while maintaining 80% of the overall efficiency, when compared to their fullerene-based counterpart.

Development of TiO2-based dye-sensitized solar cells using natural dyes extracted from some plant-based materials

The need for a green and more environmentally friendly energy production has led to recent research into the use of natural products in the production photovoltaic cells. In this study, TiO2-based dye-sensitized solar cells (DSSCs) were fabricated using photo-sensitizers made from ten natural dyes extracted from different plant parts (i.e. seeds, stalks, peels and flowers) of some selected plants and using candle soot carbon as a counter electrode. The chemical composition of the materials was determined using basic phytochemical screening assays. The extracted dye materials were characterized using UV and IR methods after which they were used in developing DSSCs. The DSSCs were then characterized under AM 1.5 illuminations to measure their photo-electrochemical properties. The dyes containing carboxyl and hydroxyl functional groups showed weak to large absorption under the visible light (400-700 nm) irradiation. The photo-electrochemical performance of the various cells gave an efficiency of as high as 0.18% with open circuit voltages ranging from 0.28 to 0.45 V and short-circuits photocurrent densities from 0.26 to 1.69 mA.cm-1. Better efficiencies can be attained by improving the DSSC constructional parameters.

High Voc Fullerene-Free Organic Photovoltaics Composed of PTB7 and Axially-Substituted Silicon Phthalocyanines

While the efficiency of organic photovoltaics (OPV) has improved drastically in the past decade, such devices rely on exorbitantly expensive materials that are unfeasible for commercial applications. Moreover, examples of high voltage single-junction devices, which are necessary for several applications, particularly low-power electronics and rechargeable batteries, are lacking in literature. Alternatively, silicon phthalocyanines (R2-SiPc) are inexpensive, industrially scalable organic semiconductors, having a minimal synthetic complexity (SC) index, and are capable of producing high voltages when used as acceptors in OPVs. In the present work, we have developed high voltage OPVs composed of Poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno [3,4 b]thiophenediyl}) (PTB7) and an SiPc derivative ((3BS)2-SiPc). Interestingly, while changes to the solvent system had a strong effect on performance, the PTB7:3BS-SiPc active layer were robust to spin speed, annealing and components ratio. This invariance is a desirable characteristic for industrial production. All PTB7:(3BS)2-SiPc devices produced high open circuit voltages between 1.0 and 1.07 V, while maintaining 80% of the overall efficiency, when compared to their fullerene-based counterpart.

Intrinsically Polar Piezoelectric Self-Assembled Oligopeptide Monolayers

<div><div><div><p>Flexible, bio-compatible piezoelectric materials are of considerable research interest for a variety of applications, but many suffer from low response or high cost to manufacture. Herein, novel piezoelectric force and touch sensors based on self-assembled monolayers of oligopeptides are presented which produce large piezoelectric voltage response and are easily manufactured without the need for electrical poling. While the devices generate modest piezoelectric charge constants (d33) of up to 9.8 pC N−1, they exhibit immense piezoelectric voltage constants (g33) up to 2 V m N−1. Furthermore, a flexible device prototype is demonstrated that produces open-circuit voltages of nearly 6 V under gentle bending motion. Improvements in peptide selection and device construction promise to further improve the already outstanding voltage response and open the door to numerous practical applications.</p></div></div></div>