Blog

The Kurt J Lesker Company has been providing Physical Vapor Deposition (PVD) systems to support photovoltaics (PV) research for more than 20 years and continues to support scientists globally to advance this critical renewable energy application. Solar cells work by using materials that absorb photons from sunlight in a broad spectral range and in turn effectively convert this captured light into free charges that produce electricity. Modern commercial solar cells are mainly based on crystalline Silicon, which is a cheap and abundant semiconductor^[1]. In recent decades, alternative thin film technologies based on materials combinations including Copper indium gallium diselenide (Cu(In,Ga)Se₂ or CIGS), Cadmium Telluride (CdTe), amorphous silicon and organic photovoltaics (OPV) have emerged with high efficiencies coupled with good cell stability, low manufacturing costs and come with the advantage of being a thin film, being both lightweight and flexible^[2].

Pittsburgh, PA - Kurt J. Lesker Company ("KJLC") today announced that it has acquired substantially all of the assets of KDF Electronics & Vacuum Services, Inc. ("KDF" or "KDF Technologies, LLC") through an asset purchase agreement.

KDF Electronics & Vacuum Services, Inc. will become known as KDF Technologies, LLC as of 12/31/2021. KDF will continue to operate independent of KJLC while leveraging some shared services.

Organic electronics research has advanced rapidly over the past few decades, with organic light-emitting diodes (OLEDs) now being commonly available in commercial devices such as mobile phones and TVs. Organic photovoltaics (OPVs, or organic solar cells) have potential to follow OLEDs as a commercially viable technology, but a number of challenges still need to be overcome. A recent publication from an international collaboration, with lead authors Prof. Moritz Riede (University of Oxford) and Dr. Ivan Ramirez (Heliatek GmbH), has investigated the degradation pathways of OPV devices using a common organic material, C₆₀, generating understanding which may prove critical to achieve long-term device stability. The complete solar cell structures used in the study were produced using a Kurt J. Lesker SPECTROS evaporation system.

Systems evacuated with oil-based pumps may be victims of backstreaming of pump oil vapors into the fore- line, vacuum chamber, and upstream throughout the system. The back- streaming referred to here is the act of pump oil vapors moving against the flow of molecules traveling from the vacuum chamber to the pump(s). In this case, we refer to these oil vapors as moving upstream, and eventually into the vacuum chamber. At high pressures, where the number of molecules from the chamber outnumber pump oil vapor molecules emanating from the pumping system, flow upstream is greatly mitigated. Oil vapor back- streaming is significantly more pronounced at lower operating pressures.

Mina Shahmohammadi from the research group of Professor Christos G. Takoudis, Full Professor in the Departments of Bioengineering and Chemical Engineering at the University of Illinois at Chicago, in collaboration with College of Dentistry, University of Illinois at Chicago, and Kurt J. Lesker Company recently developed conformal atomic layer deposition (ALD) based titanium (IV) oxide (TiO₂) thin film processes on Polymethyl Methacrylate (PMMA) displaying excellent surface and mechanical properties for potential engineering, medical, and biomedical applications. The findings were recently published in the Journal of Materials Science.

The Kurt J Lesker Company has been shipping Physical Vapor Deposition (PVD) tools into the field of perovskite solar cells for the last decade and continues to support researchers in this exciting application. Our partner, Dr. Sascha J. Wolter, along with the Future Technologies Photovoltaics group, headed by Dr. Sarah Kajari-Schröder, at the Institute for Solar Energy Research (ISFH) in Hamelin, Germany, have presented a method to determine the acoustic impedance ratio (Z) for two perovskite precursors that are commonly co-deposited using PVD. In their paper "Determination and influence evaluation of the acoustic impedance ratio for thermal evaporation"^[1] they report Z values for methylammonium iodide (MAI) of 0.025 ±0.002 and 0.11 ±0.01 for lead (II) iodide (PbI2). Furthermore, the impact of using an incorrect Z-ratio on actual experimental thermal evaporations is investigated.

To celebrate Women's History Month, we spoke with Cindy Lesker who is currently an Owner, Chairwoman, and Vice President of Information Technology at the Kurt J. Lesker Company. Earlier this year, Cindy was a finalist for the prestigious CIO of the Year award by the Pittsburgh Technology Council.

We caught up with Cindy to find out about her journey to being the Chairwoman and CIO of KJLC and what Women's History Month means to her.

When a magnetic field (B in Fig. 1 (a)) is applied to a metal, the electric current (J in Fig. 1 (a)) flowing through the metal will be deflected by the magnetic field so that it is not parallel with the applied electric field (E in Fig. 1 (a)). This phenomenon, known as the Hall effect, is well understood in the classical physics. Later, the research on magnetic materials discovered that in certain magnetic materials, the Berry phase, one of the quantum properties of electrons, can alter the motion of electrons without the presence of an external magnetic field (Fig. 1 (b)). This phenomenon is known as the anomalous Hall effect (AHE). In AHE experiments, two quantities are measured: The longitudinal conductivity σ_xx, which is the conductivity of the material along the direction of the electric field; and the transverse conductivity σ_xy, which is the conductivity along the perpendicular direction of the electric field. The ratio between σ_xy and σ_xx, defined as the anomalous Hall angle, measures the strength of the intrinsic deflection by the Berry phase: The higher the σ_xy/σ_xx is, the more prominent the Berry phase is.

As we come to the end of Black History Month, we wanted to reflect on the diversity of our customers working with vacuum science and highlight the remarkable achievements in their field of research. To do this, we reached out to one of our wonderful customers, Philip Adderley, who is currently a High Vacuum Associate at a National Research Laboratory based in Virginia.

Phil studied Physics at Morehouse College in Atlanta (B.A.) and Atlanta University (M.A.), before embarking on a career in vacuum at a prestigious National Research Laboratory in Illinois, where he had a major role in the development of the kicker magnets for the antiproton accumulator ring. He also developed the conductive coating for the ceramic beam tubes for these magnets. This period allowed him to pick up extensive expertise in vacuum and alignment technologies.

To recognize the International Day of Women and Girls in Science and to celebrate all the amazing female customers in scientific research we work with, we reached out to Laura Wagner - a PhD researcher at TU Munich's Walter Schottky Institute (WSI) and Physics Department - to discuss her career path so far, the exciting research she is currently working on with her team, and what this day means to her a as a female scientist at an exciting point in her career.