Japan Science and Technology Agency (JST) and the University of Tokyo announced on May 16, 2011 that Associate Professor Keisuke Tajima of the University of Tokyo and his colleagues succeeded in improving output voltage of organic thin-film photovoltaic cells by tailoring bilayer interfaces under the support of JST. Details are published online in Nature Materials on May 15, 2011*.
Although thin-film organic photovoltaic cells are featured for the possibilities of flexibility, low cost, and mass production, its challenge is the improvement of conversion efficiency. Interfacial layer between two materials composing the cells is crucial to determine the performance, because light-generated excitons at the interface are separated to electrons and holes to generate electricity.
Researchers connected two films of organic semiconductor P3HT (poly(3-hexylthiophene)) and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) by film-transfer method without disturbing their flat surface. Each film can further be modified with a surface-segregated monolayer to tune the strength and direction of the surface dipole moment.
Bilayer organic photovoltaic devices were fabricated with interfacial dipole moments that were selected to align upward or downward at the junction between P3HT and PCBM. The open-circuit voltage of the P3HT/PCBM devices was varied from 0.3 to 0.95 V with the direction of dipole moments. The best result far more exceeded the open-circuit voltage of 0.55-0.6V ordinarily obtained in P3HT/PCBM cells without interfacial modification. Improved open-circuit voltage is realized by tailoring bilayer interfaces.
*Akira Tada, Yanfang Geng, Qingshuo Wei, Kazuhito Hashimoto, and Keisuke Tajima, "Tailoring or-ganic heterojunction interfaces in bilayer polymer photovoltaic devices", Nature Materials, Published online: 15 May 2011 | doi: 10.1038/nmat3026
Robot on demand: Mobile machining of aircraft components with high precision
06.12.2016 | Fraunhofer IFAM
IHP presents the fastest silicon-based transistor in the world
05.12.2016 | IHP - Leibniz-Institut für innovative Mikroelektronik
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine