Control of carrier mobilities for performance enhancement of anthracene-based polymer solar cells

International audienceHigh performance organic solar cells were realized using an anthracene-based polymer. Charge carrier mobilities of both electrons and holes in solvent annealed polymer and fullerene derivative mixtures were studied using organic field-effect transistors. Fine tuning of donor to acceptor ratios revealed optimum conditions for balanced mobilities, which led to a high power conversion efficiency (PCE) of 4.02% in the organic solar cells. A methanol wash approach further enhanced the PCE to 4.65%. This work demonstrates the importance of carrier transport control in optimizing the performance of polymer solar cells

J.Mater.Chem.C

Correction for ‘“Heavy-atom effects” in the parent [1]benzochalcogenopheno[3,2-b][1]benzochalcogenophene system’ by Chengyuan Wang et al., J. Mater. Chem. C, 2020, 8, 15119–15127, DOI: https://doi.org/10.1039/D0TC01408G

Formation of TiO2 nanostructures modified Eumelanin films with enhanced properties for biopolymer implementations

Thin films of hybrid melanin-TiO2 nanoparticles (eumelanin: TiO2) deposited from solution by electro-spray were accurately inspected to unveil modified structural and electronic properties for device implementations. Based on the reorganization of the melanin electronic valence orbital, among other interesting behaviors, we observed up to a two orders increase in the absorption coefficient in the visible range. Furthermore the redshifted absorption features, disclose that the extended π- stacking of oligomers is mainly responsible for the tunability of the optical gap as confirmed by photoluminescence. TiO2 nanostructures via oxidative polymerization, further improve the oligomeric character observed by means of Raman scattering. Finally, the photocatalytic activity of TiO2 nanoparticles helps the saturation of shallow trap states in melanin structure and consequently enhances the charge carrier transport

XANES investigation of the local structure of Co nanoclusters embedded in Ag

Ion-implanted cobalt atoms into a silver matrix with a layer thickness of about 20 nm were studied by x-ray absorption near-edge spectroscopy (XANES) at the Co $K$ edge. Full multiple scattering ab initio calculations of Co XANES at the $K$ edge provide a phase fingerprint to distinguish the Co structure of samples prepared at different doses and annealing temperatures. The bcc Co phase is formed for the as-prepared sample with 6 at. % and the fcc Co phase is formed at the expense of the bcc phase for the sample with 12 at. % after annealing at $400\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.

Effect of additive in fullerene and non-fullerene acceptor organic solar cells

National audienc

Balancing charge carrier mobilities in bulk heterojunction organic solar cells

International audienc

Balancing charge carrier mobilities in bulk heterojunction organic solar cells

International audienc

Balancing charge carrier mobilities in bulk heterojunction organic solar cells

International audienc

Electron beam versus thermal deposition of aluminum top electrode for organic solar cells

The current–voltage characteristics and photovoltaic parameters of polymer solar cells with Al cathode separately deposited by thermal and electron beam methods were compared. The power conversion efficiency of as prepared electron beam deposited device is ten times lower than that of thermal evaporated one. However, after post-annealing, device performance parameters of electron beam deposited device sharply increased and reached almost the same values as thermal evaporated device. Through the analysis of J-V characteristics in the dark, the formation of deep traps at the interface induced by electron beam, as reported in earlier studies, was excluded