Institute for Materials Science

Tel: +49 (0)201 183-2737
Office: V15 S05 D20

doru.lupascu@uni-due.de

0000-0002-6895-1334

ResearchGate

Scopus

In the last decade, a new class of absorber materials for solar cells has emerged: the perovskite organic-inorganic halides, shortly called “perovskites”. These perovskites exhibit exceptional charge carrier lifetime and resistance to point defect-based charge carrier recombination. This outstanding performance parameter allows for comparatively “dirty” crystals containing a large amount of point defects like ionic vacancies, interstitials or non-charge neutral substitutions.

In the context of this research, we identified the dielectric constant to be the critical parameter to screen defects and enable the break-up of the excitonic state in the initial stage of charge generation from the absorbed light.

Selected publications

I. Anusca, …, D.C. Lupascu, Dielectric Response: Answer to Many Questions in the Methylammonium Lead Halide Solar Cell Absorbers, Advanced Energy Materials 7, 1700600 (2017)

Š. Svirskas, …, D.C. Lupascu, J. Banys, Phase transitions, screening and dielectric response of CsPbBr₃​, Journal of Materials Chemistry A 8 (28), 14015 – 14022 (2020)

Y.U. Jin, B. Marler, A.N. Salak, M. Escobar-Castillo, N. Benson, D.C. Lupascu, Perovskite-inspired low-dimensional hybrid azetidinium bismuth halides: [(CH₂)₃NH₂]₃Bi₂X₉ (X = I, Br, Cl), Mater. Chem. Front. 9, 1002 – 1012 (2025)

Y.U. Jin, …, D.C. Lupascu, Lead-free organic–inorganic azetidinium alternating metal cation bromide: [(CH₂)₃NH₂]₂AgBiBr₆, a perovskite-related absorber, RSC Advances 13, 36079 – 36087 (2023)

Fatigue in ferroelectrics was a significant challenge in the period from 1995 until around 2010, when piezoelectric actuators as well as ferroelectric computer memories were rapidly developing technologies in industry. The biggest problem was their fatigue under periodic electrical loading. I contributed over 60 publications and a monography to the field of ferroelectric fatigue, comprehensively addressing the electric, physicochemical, and mechanical effects responsible for degradation. This included in depth mechanical characterization of the materials. The major mechanisms behind fatigue of ferroelectrics were resolved.

Selected publications

D.C. Lupascu, Fatigue of Ferroelectric Ceramics and Related Issues, Springer, Heidelberg (2004)

D.C. Lupascu, J. Rödel, Fatigue in Bulk Lead Zirconate Titanate Actuator Materials, Adv. Engin. Mater. 7 (10), 882 – 898 (2005)

D.C. Lupascu, U. Rabe, Cyclic cluster growth in ferroelectric perovskites, Phys. Rev. Lett. 89 (18), 187601 (2002)

N. Balke, H. Kungl, T. Granzow, M. Hoffmann, D.C. Lupascu, J. Rödel, Bipolar fatigue caused by field screening in Pb(Zr,Ti)O₃ ceramics, J. Am. Ceram. Soc. 90 (12), 3869 – 3874 (2007)

I. Westram, W.S. Oates, D.C. Lupascu, J. Rödel, C.S. Lynch, Mechanism of electric fatigue crack growth in lead zirconate titanate, Acta Mater. 55, 301 – 312 (2007)

Throughout the last 15 years this research expanded to magnetoelectric composites, multiferroic Bismuth Ferrite, relaxor ferroelectricity, electrocaloric studies, as well as (true) halide perovskite ferroelectrics.

Selected publications

M. Etier, …, D.C. Lupascu, Magnetoelectric Coupling in Multiferroic Cobalt Ferrite-Barium Titanate Ceramic Composites with Different Connectivity Schemes, Acta Materialia 90, 1 – 9 (2015)

A. Dubey, …, D.C. Lupascu, Mono-, Di-, and Tri-valent Cation Doped BiFe_0.95Mn_0.05O₃ Nanoparticles: Ferroelectric Photocatalysts, Adv. Funct. Mater. 32 (43), 2207105 (2022)

V.V. Shvartsman, D.C. Lupascu, Lead free relaxor ferroelectrics, J. Am. Ceram. Soc. 95 (1), 1 – 26 (2012)

M. Sanlialp, V.V. Shvartsman, M. Acosta, B. Dkhil, D.C. Lupascu, Strong electrocaloric effect in lead-free 0.65Ba(Zr_0.2Ti_0.8)O₃-0.35(Ba_0.7Ca_0.3)TiO₃ ceramics obtained by direct measurements, Appl. Phys. Lett. 106, 062901 (2015)

An early highlight of my career was resolving a long-standing question of the γ–γ perturbed angular correlation (PAC) spectroscopy during my PhD in Göttingen. Herein, I identified the mechanism behind the after-effect seen in many PAC datasets by developing a theory regarding the role of the relaxation of electrons in the atom after the nuclear capture of its core shell electron. Further, I successfully used the method to disentangle and identify the dominating transport mechanisms in various rare earth oxides. Based on my expertise in the field, I assumed the responsibility of running the solid-state beamlines of ISOLDE/CERN in 2016 and have been doing so since. As a recent scientific highlight of this research branch, we have disproven the supposed magnetoelectric nature of bismuth ferrite, which is an effect that had been attributed to this material for decades.

Selected publications

D. Lupascu et al., Relaxation of electronic defects in pure and doped La₂O₃ observed by perturbed angular correlations, Phys. Rev. B 54, 871 (1996)

S. Habenicht, D. Lupascu, M. Uhrmacher, L. Ziegeler, K.P. Lieb, ISOLDE Collaboration, PAC-Studies of Sn-doped In₂O₃: Electronic defect relaxation following the ¹¹¹In(EC)¹¹¹Cd-decay, Zeitschrift f. Physik B 101, 187 – 196 (1996)

D. Lupascu, M. Uhrmacher, K.P. Lieb, Electric field gradients of ¹¹¹Cd in monoclinic (B-phase) rare earth sesquioxides, Journal of Physics: Condensed Matter 6, 10445 (1994)

K. Johnston, …, D. Lupascu, …, A. Costa, The solid state physics programme at ISOLDE: recent developments and perspectives, Journal of Physics G: Nuclear and Particle Physics 44, 104001 (2017)

T.T. Dang, …, D.C. Lupascu, Magnetoelectric Decoupling in Bismuth Ferrite, Phys. Rev. Lett. 134, 216702 (2025)

The Institute for materials science in civil engineering has a history of pioneering fundamental research in civil engineering materials. Recently, much research at the institute is dedicated to the understanding of cement recycling through thermal reactivation, which is tackling the issue of one of the biggest carbon emitters in industry worldwide. We have recently shown that a viable cement binder can be achieved from thermally re-activated cement from recycled concrete. The research spans from separation, diminution, thermal activation, flow behavior to the strengths that can ultimately be re-achieved in this new class of binders. A full fracture mechanical understanding of the matter is an asset we uniquely provide.

Selected publications

G. Semugaza, …, D.C. Lupascu, Reactivation of hydrated cement powder by thermal treatment for partial replacement of ordinary Portland cement, Materials and Structures 56, 48 (2023)

N. Noel, …, D.C. Lupascu, Chemical transformations during the preparation and rehydration of reactivated virgin cements, Cement 19, 100129 (2025)

N. Noel, …, D.C. Lupascu, Role of ground blast furnace slag (GBFS) as a micro-milling and micro-aggregating agent in reactivated cement fines (RCFs), Journal of Sustainable Cement-Based Materials 15 (2), 495 – 516 (2025)

A.Z. Gierth, M. Elies, S. Helmich, N. Noel, T. Mielke, D.C. Lupascu, Influence of additives on the fracture mechanical properties of reactivated cement paste, FraMCoS-XII Conference – Fracture Mechanics for Concrete and Concrete Structures, Vienna, Austria (2025)

Based on the longstanding expertise in fracture mechanics of concrete, we could contribute to the understanding of the properties of Antarctic sea ice taking part in three expeditions to the Antarctic marginal ice zone. We identified the viscous properties of frazil ice during the freezing process and the ultimate strength of the consolidated sea ice. Our long-standing experience in mechanical testing of materials helped to design viable and transportable measuring devices.

Selected publications

F. Paul, …, D.C. Lupascu, Frazil Ice in the Antarctic Marginal Ice Zone, J. Marine Sci. Eng. 9 (6), 647 (2021)

S. Skatulla, …, D.C. Lupascu, …, M. Vichi, Physical and mechanical properties of winter first-year ice in the Antarctic marginal ice zone along the Good Hope Line, The Cryosphere 16, 2899 – 2925 (2022)

F. Paul, …, D.C. Lupascu, Sea ice mechanics, Computer Methods in Materials Science 23 (3), 5 – 54 (2023)

The duties of my teaching lie in the primary years of civil engineers. Physics for Civil Engineers, Introduction to Materials Science, Experimental Materials Mechanics (Werkstoffe 3) are the topics taught by myself. The lecture Solar Cells (Werkstoffe 10) is my contribution to the Master curriculum.

So far 25 PhD theses have been accomplished under my supervision, 16 are presently in different phases of completing their graduation.