Examinando por Autor "Contreras, Pedro"

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A Comparative Study of Recombination Mechanisms and Long-Term Outdoor Degradation in Perovskite Solar Cells and Modules Including Self-Assembled Monolayers
(Wiley, 2025-06-17) Delgado-Rodríguez, Silvia; Pozo, Gonzalo del; Contreras, Pedro; Arredondo, Belén; Vishwanathreddy, Sujith; Parion, Jonathan; Ramesh, Santhosh; Aernouts, Tom; Aguirre, Aranzazu; Romero, Beatriz
Perovskite solar cells are one of the most promising photovoltaic technologies in the last decades. Inverted (p–i–n) cells using NiOX as hole-transport layer (HTL) have gained attention due to their easy fabrication methods and high stability, although they often exhibit reduced efficiencies due to non onlyoptimized energy-level alignment. To address this issue, different approaches have been developed, such as the use of self-assembled monolayers (SAMs) on top of the HTL. Herein, a comparative study between regular p–i–n cells and cells using Me-PACz as an SAM on top of NiOX is we presented. Devices with SAM exhibit enhanced open-circuit voltage and efficiency. Temperature DC and AC characterization reveals that the incorporation of SAM reduces recombination at the interface, as seen from the comparison of the perovskite bandgap (1.6 eV) and carrier activation energy ≈1.1 and ≈1.59 eV for reference and SAM, respectively. Finally, an outdoor degradation experiment with minimodules has been conducted. The experiment spanned for more than 500 days, and results show that minimodules with SAM were less stable than those based on the reference layer structure. This is due to a severe decrease in the short-circuit current, which could be attributed to a deterioration of the SAM spacer.
High stable CsFAPbIBr perovskite solar cells with dominant bulk recombination at real operating temperatures
(Royal Society of Chemistry, 2023-05-02) Romero, Beatriz; Delgado, silvia; Glowienka; Chang, Cheng-Tsung; del Pozo, Gonzalo; Arredondo, Belén; Martin-Martin, Diego; Contreras, Pedro; Galagan, Yulia
Mixed-cation mixed-halide perovskite solar cells have been characterized in DC at different temperatures (from -20 degrees C up to 50 degrees C) and the time evolution of the device efficiency has been assessed using different degradation protocols (indoors and outdoors). The completely planar p-i-n structure is ITO/CuNiOx/PTAA/CsFAPbIBr/PCBM/PEI/Ag. Pristine current-voltage characteristics barely show hysteresis, at any temperature. Open circuit voltage decreases with temperature at a rate of -1.5 mV degrees C-1, and the obtained PCE temperature coefficient is lower than -0.001% K-1, which is an outstanding value for this emerging photovoltaic technology. Cells have been degraded under different protocols: indoors using different light/dark cycles and outdoors in a high temperature and high irradiation location. Cells show no significant decrease of the efficiency after more than 350 h of indoor light cycling and the estimated T-80 obtained for the sample degraded outdoors under high irradiation and high temperature conditions is similar to 15 days.