https://opendata.uni-halle.de//handle/1981185920/35794 2026-04-11T23:50:09Z 2026-04-11T23:50:09Z Romanyuk, Yaroslav E. Haass, Stefan G. Giraldo, Sergio Placidi, Marcel Tiwari, Devendra Fermin, David J. Hao, Xiaojing Xin, Hao Schnabel, Thomas Kauk-Kuusik, Marit Pistor, Paul Lie, Stener Wong, Lydia H. https://opendata.uni-halle.de//handle/1981185920/124779 2026-04-01T20:00:53Z 2019-01-01T00:00:00Z

Title: Doping and alloying of kesterites Author(s): Romanyuk, Yaroslav E.; Haass, Stefan G.; Giraldo, Sergio; Placidi, Marcel; Tiwari, Devendra; Fermin, David J.; Hao, Xiaojing; Xin, Hao; Schnabel, Thomas; Kauk-Kuusik, Marit; Pistor, Paul; Lie, Stener; Wong, Lydia H. Abstract: Attempts to improve the efficiency of kesterite solar cells by changing the intrinsic stoichiometry have not helped to boost the device efficiency beyond the current record of 12.6%. In this light, the addition of extrinsic elements to the Cu2ZnSn(S,Se)4 matrix in various quantities has emerged as a popular topic aiming to ameliorate electronic properties of the solar cell absorbers. This article reviews extrinsic doping and alloying concepts for kesterite absorbers with the focus on those that do not alter the parent zinc-blende derived kesterite structure. The latest state-of-the-art of possible extrinsic elements is presented in the order of groups of the periodic table. The highest reported solar cell efficiencies for each extrinsic dopant are tabulated at the end. Several dopants like alkali elements and substitutional alloying with Ag, Cd or Ge have been shown to improve the device performance of kesterite solar cells as compared to the nominally undoped references, although it is often difficult to differentiate between pure electronic effects and other possible influences such as changes in the crystallization path, deviations in matrix composition and presence of alkali dopants coming from the substrates. The review is concluded with a suggestion to intensify efforts for identifying intrinsic defects that negatively affect electronic properties of the kesterite absorbers, and, if identified, to test extrinsic strategies that may compensate these defects. Characterization techniques must be developed and widely used to reliably access semiconductor absorber metrics such as the quasi-Fermi level splitting, defect concentration and their energetic position, and carrier lifetime in order to assist in search for effective doping/alloying strategies.

2019-01-01T00:00:00Z Grossberg, Maarja Krustok, Jüri Hages, Charles J. Bishop, Douglas M. Gunawan, Oki Hempel, Hannes Lyam, Samantha M. Hempel, Hannes Levcenco, Sergiu Unold, Thomas https://opendata.uni-halle.de//handle/1981185920/124778 2026-04-01T20:00:45Z 2019-01-01T00:00:00Z

Title: The electrical and optical properties of kesterites Author(s): Grossberg, Maarja; Krustok, Jüri; Hages, Charles J.; Bishop, Douglas M.; Gunawan, Oki; Hempel, Hannes; Lyam, Samantha M.; Hempel, Hannes; Levcenco, Sergiu; Unold, Thomas Abstract: Kesterite Cu2ZnSn(SxSe1-x)4 (CZTSSe) semiconductor materials have been extensively studied over the past decade, however despite significant efforts, the open circuit voltage remains below 60% of the theoretical maximum. Understanding the optical and electrical properties is critical to explaining and solving the voltage deficit. This review aims to summarize the present knowledge of optical and electrical properties of kesterites and specifically focuses on experimental data of intrinsic defects, charge carrier density and transport, and minority carrier lifetime and related rate-limiting recombination mechanisms. It concludes with suggestions for further investigation of the electrical and optical properties of kesterite materials.

2019-01-01T00:00:00Z Pavel, Ioana Zinuca Csuk, René Danciu, Corina Avram, Stefana Baderca, Flavia Cioca, Andreea Moacă, Elena-Alina Mihali, Ciprian-Valentin Pinzaru, Iulia Muntean, Danina Mirela Dehelean, Cristina Adriana https://opendata.uni-halle.de//handle/1981185920/124777 2026-04-01T20:00:50Z 2019-01-01T00:00:00Z

Title: Assessment of the antiangiogenic and anti-inflammatory properties of a maslinic acid derivative and its potentiation using zinc chloride Author(s): Pavel, Ioana Zinuca; Csuk, René; Danciu, Corina; Avram, Stefana; Baderca, Flavia; Cioca, Andreea; Moacă, Elena-Alina; Mihali, Ciprian-Valentin; Pinzaru, Iulia; Muntean, Danina Mirela; Dehelean, Cristina Adriana Abstract: Maslinic acid is a pentacyclic triterpene with a plethora of biological activities, including anti-inflammatory, antioxidant, antimicrobial, cardioprotective, and antitumor effects. New derivatives with improved properties and broad-spectrum activity can be obtained following structural changes of the compound. The present study was aimed to characterize a benzylamide derivative of maslinic acid—benzyl (2α, 3β) 2,3-diacetoxy-olean−12-en-28-amide (EM2)—with respect to the anti-angiogenic and anti-inflammatory effects in two in vivo experimental models. Consequently, the compound showed good tolerability and lack of irritation in the chorioallantoic membrane assay with no impairment of the normal angiogenic process during the tested stages of development. In the acute ear inflammation murine model, application of EM2 induced a mild anti-inflammatory effect that was potentiated by the association with zinc chloride (ZnCl2). A decrease in dermal thickness of mice ears was observed when EM2 and ZnCl2 were applied separately or in combination. Moreover, hyalinization of the dermis appeared only when EM2 was associated with ZnCl2, strongly suggesting the role of their combination in wound healing.

2019-01-01T00:00:00Z Band, Tino Mälzer, Till Wickert, Sandra Leipner, Hartmut S. Ebbinghaus, Stefan Dörr, Kathrin Diestelhorst, Martin https://opendata.uni-halle.de//handle/1981185920/124776 2026-04-01T20:00:41Z 2019-01-01T00:00:00Z

Title: Three different mechanisms of self-discharge behavior in poly(vinylidene fluoride-hexafluoropropylene) for dielectric energy storage Author(s): Band, Tino; Mälzer, Till; Wickert, Sandra; Leipner, Hartmut S.; Ebbinghaus, Stefan; Dörr, Kathrin; Diestelhorst, Martin Abstract: Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) has attracted attention as a matrix material for nanodielectrics, combining the high electrical breakdown of the polymer with the high permittivity of nanoparticles for improved energy storage properties. Although a large number of published works have reported increased discharged energy density for various nanocomposites, polarization and conduction loss mechanisms are rarely investigated. The latter are closely linked to the self-discharge behavior, which is crucial for future applications. This work aims to improve knowledge about loss and self-discharge mechanisms in doctor-blade-coated P(VDF-HFP) since its role in nanodielectrics is not fully understood. Combined analysis of cyclic unipolar electric displacement–electric field (D–E) characteristics and charging–lift–discharging measurements, where the measurement tip is lifted for a specific time between charging and discharging processes, reveals three Debye processes with different relaxation times: 20, 130 and 1340 s. The fast one correlates with the intrinsic conductivity of the polymer, which is dominated by space charge at high electric fields. The other two processes appear to saturate at an electric field of 100 MV m−1 so that their contribution to permittivity drops.

2019-01-01T00:00:00Z