http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/5715 2026-09-02T19:34:27Z 2026-09-02T19:34:27Z Frasca, C. Alippi, P. Schwiddessen, R. Prashanthan, K. Nasti, G. Zuo, S. Ur Rehman, M.O. Aldamasy, M.H. Hartono, N.T.P. Musiienko, A. Abate, A. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12960 2026-09-01T08:23:13Z 2025-01-01T00:00:00Z

Mitigation of Self-p-Doping and Off-Centering Effect in Tin Perovskite via Strontium Doping Frasca, C.; Alippi, P.; Schwiddessen, R.; Prashanthan, K.; Nasti, G.; Zuo, S.; Ur Rehman, M.O.; Aldamasy, M.H.; Hartono, N.T.P.; Musiienko, A.; Abate, A. Tin-based perovskite solar cells offer a less toxic alternative to their lead-based counterparts. Despite their promising optoelectronic properties, their performances still lag behind, with the highest power conversion efficiencies reaching around 15%. This efficiency limitation arises primarily from electronic defects leading to self-p-doping and stereochemical activity of the Sn(II) ion, which distorts the atomic arrangement in the material. In this study, we investigate the effect of strontium doping in tin-based perovskite on the distortion of the material’s structure and its optoelectronic properties. Using a combination of Density Functional Theory calculations and experiments, we demonstrate that strontium doping reduces p-doping and structural strain. This approach improves the efficiency from 6.3% in undoped devices to 7.5% in doped devices without relying on dimethyl sulfoxide, a harmful solvent for tin-based perovskites. This method could enable precise control of tin off-centering and self-p-doping, advancing the development of efficient and stable tin perovskite solar cells.

2025-01-01T00:00:00Z Zuo, S. Tarasov, A. Frohloff, L. Prashanthan, K. Ruske, F. Lounasvuori, M. Frasca, C. Dallmann, A. Zu, F. Mathies, F. Scheler, F. Hartono, N.T.P. Guixiang, L. Jinzhao, L. Simmonds, M. Wenhui, L. Koch, N. Albrecht, S. Meng, L. Unger, E. Aldanmasy, M.H. Musiienko, A. Abate, A. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12959 2026-09-02T03:39:11Z 2025-01-01T00:00:00Z

Tailored Crystallization Dynamics for Efficient and Stable DMSO-Free Tin Perovskite Solar Cells Zuo, S.; Tarasov, A.; Frohloff, L.; Prashanthan, K.; Ruske, F.; Lounasvuori, M.; Frasca, C.; Dallmann, A.; Zu, F.; Mathies, F.; Scheler, F.; Hartono, N.T.P.; Guixiang, L.; Jinzhao, L.; Simmonds, M.; Wenhui, L.; Koch, N.; Albrecht, S.; Meng, L.; Unger, E.; Aldanmasy, M.H.; Musiienko, A.; Abate, A. Tin perovskite solar cells are emerging as a sustainable lead-free alternative in thin film photovoltaics. DMSO-free processed tin perovskites are gaining interest due to the detrimental effects of DMSO on tin oxidation. However, replacing DMSO with other solvents remains challenging due to the accelerated crystallization dynamics in non-DMSO systems. In this study, the crystallization process in a DMSO-free solvent system is regulated by managing the transition from the sol-gel phase to the solid film. Specifically, piperazine dihydriodide (PDAI) and 4-tert-butylpyridine (tBP) are utilized to coordinately tune the colloidal chemistry through forming large pre-nucleation clusters in perovskite ink, further, facilitating the film formation process. By combining tBP and PDAI, a controllable crystallization rate is achieved as evidenced by in situ photoluminescence (PL) measurement during spin-coating. As a result, tin perovskite films show high crystallinity and improved microstructure. Devices treated with tBP+PDAI exhibit a champion power conversion efficiency of 7.8% and excellent stability without observable degradation for over 3000 h stored in the N2 glovebox. These findings advance understanding and managing crystallization in DMSO-free solvents processed tin perovskite solar cells.

2025-01-01T00:00:00Z Amalraj, P.A. Loheeswaran, S. Landova, L. Neykova, N. Holovský, J. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12859 2026-08-10T04:58:53Z 2025-01-01T00:00:00Z

Polymer-Assisted Crystallization and Defect Passivation in Planar Wide-Bandgap FAPbBr3 Perovskite Solar Cells Amalraj, P.A.; Loheeswaran, S.; Landova, L.; Neykova, N.; Holovský, J. Wide-bandgap lead bromide perovskites such as FAPbBr 3 are promising candidates for tandem solar cells and high-voltage optoelectronic applications, yet their performance is limited by surface and bulk defects that induce severe nonradiative recombination and limit stability. In this work, we present a defect passivation and crystallization control strategy by incorporating poly­(methyl methacrylate) (PMMA) into the antisolvent during FAPbBr 3 film fabrication. PMMA treatment leads to improved film morphology with larger grains, reduced surface roughness, and enhanced crystallinity. FTIR analysis reveals that the carbonyl groups in PMMA coordinate with undercoordinated Pb 2+ ions, effectively passivating electronic trap states. Photothermal deflection spectroscopy (PDS) shows reduced sub-bandgap absorption and lower Urbach energy, indicating suppressed deep-level defects and reduced energetic disorder. Enhanced photoluminescence intensity, prolonged carrier lifetimes, and decreased trap densities further confirm suppressed nonradiative recombination. As a result, PMMA treatment increases Voc by over 100 mV and improves power conversion efficiency by more than 1%, achieving a Voc of up to 1.510 V with reduced hysteresis and improved ambient stability. These findings demonstrate the effectiveness of polymer-assisted strategies for improving both efficiency and stability of wide-bandgap perovskite solar cells, offering a pathway toward high-voltage and tandem photovoltaic applications.

2025-01-01T00:00:00Z Amalraj, P.A. Horynova, E. Holovsky, J. Landova, L. Jain, N. Pakki, A.D. Kuo, M.H. Pelikánová, I.B, Dzurňák, B. Horák, L. Pop-Georgievski, O. Neda, N. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12855 2026-08-07T05:04:25Z 2025-01-01T00:00:00Z

Nickel oxide hole transport layer for perovskite solar cells: Preparation via pulsed laser deposition with simulation and experimental insights Amalraj, P.A.; Horynova, E.; Holovsky, J.; Landova, L.; Jain, N.; Pakki, A.D.; Kuo, M.H.; Pelikánová, I.B,; Dzurňák, B.; Horák, L.; Pop-Georgievski, O.; Neda, N. Nickel oxide (NiOx) has gained attention as a promising inorganic hole transport layer for perovskite solar cells due to its wide bandgap, high transparency, and stability. However, tuning of band alignment by an extra dipole layer is necessary to achieve high efficiencies. Our predictive simulations suggest that NiOx bandgap tuning can also improve solar cell performance. Motivated by these findings, this study experimentally investigates NiOx films with different bandgap fabricated using pulsed laser deposition under varying deposition conditions, including oxygen pressure, substrate temperature and laser frequency. Our outcomes show that mainly the deposition temperature significantly influences the chemical composition, optical properties, and defect states in the NiOx films, lattice constants and morphology as confirmed by X-ray photoelectron spectroscopy, photothermal deflection spectroscopy, X-ray diffraction spectroscopy, atomic force microscopy and scanning electron microscopy. Experimentally, FA0.83Cs0.17Pb(I0.6Br0.4)3 mixed halide perovskite solar cells were fabricated on NiOx substrates prepared under varying oxygen pressures and pulse numbers, achieving a maximum power conversion efficiency of approximately 8 %. This demonstrates that NiOx deposited by pulsed laser deposition, when properly tuned, is a promising candidate for an efficient hole transport layer in perovskite-based photovoltaics.

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