Diarylamino-substituted Tetraarylethene (TAE) as Efficient and Robust Hole Transport Material for 11% Methyl Ammonium Lead Iodide Perovskite Solar Cells.

We report the synthesis and characterisation of tetra{4-[N,N-(4,4′-dimethoxydiphenylamino)]phenyl}ethene (TAE-1) as an efficient and robust hole transport material for its application in methyl ammonium lead iodide (MAPI) perovskite solar cells. The solar cells show light-to-energy conversion efficiencies as high as 11.0% under standard measurement conditions without the need of additional dopants

Analysis of Photoinduced Carrier Recombination Kinetics in Flat and Mesoporous Lead Perovskite Solar Cells

In this work, we analyze the carrier recombination kinetics and the associated charge carrier density in methylammonium lead iodide perovskite (MAPI) solar cells that use mesoporous TiO2, as selective contact (m-MAPI) and flat solar cells (without the mesoporous TiO2 f-MAPI), which are the most common device architectures for perovskite solar cells. The use of PIT-PV (photoinduced transient photovoltage) and L-TAS (laser transient absorption spectroscopy) showed that for devices that cannot reach efficiencies close to 19% there is a slow component of the photovoltage decay that corresponds to a charge recombination pathway for carrier losses responsible for the lower device efficiency. Moreover, we have also identified a primary interfacial charge recombination pathway for carrier losses that is common in all devices studied, independent of their efficiency or their device structure, which we have associated with the recombination reaction between electrons in the perovskite and holes in the organic semiconductor material used as the selective contact

High open circuit voltage in efficient thiophene-based small molecule solution processed organic solar cells

International audienceWe have synthesized and fully characterized an oligothiophene small organic molecule for its use as electron donor moiety in solution processed bulk-heterojunction organic solar cells. Our results show that device solvent annealing process of the conjugated oligothiophene molecule leads to a light-to-energy conversion efficiency of 3.75% under standard illumination conditions. The solar cell presents open-circuit voltage and fill factors as high as 1.01 V and 63.05% respectively, which are among the highest values obtained for small molecule solution processed organic solar cells

Low Open-Circuit Voltage Loss in Solution-Processed Small-Molecule Organic Solar Cells

We analyze the voltage losses at open circuit in solution-processed, small-molecule:fullerene blend solar cells, using electroluminescence and external quantum efficiency measurements and the reciprocity relationship between light absorption and emission. For solar cells made from oligo-thienylenevinylene-based donors and phenyl-C71 butyric acid methyl ester (PC71BM), we find that the voltage loss due to the finite breadth of the absorption edge is remarkably small, less than 0.01 eV in the best cases, while the voltage loss due to nonradiative recombination reaches 0.29 eV, one of the smallest values reported for an organic solar cell. As a result, the open-circuit voltage reaches around 1.0 V for an optical gap of 1.6 eV, greatly exceeding the voltage of a high-performance polymer-based system with similar optical gap. We assign the remarkably small absorption broadening loss to a low degree of energetic disorder in the small-molecule system that allows efficient charge separation at a lower driving force than in typical conjugated polymer blends

Fully Solution-Processed n–i–p-Like Perovskite Solar Cells with Planar Junction: How the Charge Extracting Layer Determines the Open-Circuit Voltage

Fully solution-processed direct perovskite solar cells with a planar junction are realized by incorporating a cross-linked [6,6]-phenyl-C61-butyric styryl dendron ester layer as an electron extracting layer. Power conversion efficiencies close to 19% and an open-circuit voltage exceeding 1.1 V with negligible hysteresis are delivered. A perovskite film with superb optoelectronic qualities is grown, which reduces carrier recombination losses and hence increases V oc