Evaluation of the stability of perovskite solar cells using MPPT and nonlinear spectroscopy.

• Grant number: 25/11855-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Engineering - Electrical Engineering - Electrical, Magnetic and Electronic Measurements, Instrumentation
• Principal Investigator: Carlos Frederico de Oliveira Graeff
• Grantee: José Renato de Melo Neto
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil
• Associated research grant: 20/12356-8 - Stability optimization of perovskite solar cells, AP.TEM

Abstract

Perovskite solar cells (PSCs) are among the most promising emerging photovoltaictechnologies due to their superior optoelectronic properties and low-cost, solution-basedprocessing. Their power conversion efficiency has risen from 3.8% to over 26% in the past15 years. At this stage, advanced diagnostic techniques are crucial to assess device stabilityand support their future commercialization. While JV curves remain standard forperformance evaluation, they lack temporal resolution and fail to capture complex internaldynamics. Impedance spectroscopy (IS), employing small-signal perturbations across a widefrequency range, offers deeper insight but is often limited to linear regimes. Key degradationphenomena-such as ion migration, recombination, hysteresis, and anomalouscapacitance-are nonlinear, generating higher-order harmonics under oscillatory excitationand requiring more comprehensive spectral analysis. Maximum power point tracking (MPPT)methods provide more accurate assessments of operational stability compared to static JVmeasurements, particularly in the presence of hysteresis effects induced by voltage sweepdirection and step size. Optimizing MPPT algorithms complements traditionalcharacterization and improves reliability. This project proposes a detailed study of PSCsbased on the mixed-cation formulation Cs0.17FA0.83Pb(I0.83Br0.17)3, in both standard (n-i-p) and inverted (p-i-n) architectures. We will evaluate the impact of aging, environmental exposure,and device engineering strategies-including buffer layers (PMMA, PEI, BCP) and dopantadditives (e.g., MXenes)-on charge transport and stability. By integrating IS with time-domain techniques and MPPT tracking, this research aims to establish a robust frameworkfor the electrical characterization and optimization of PSCs, contributing to enhancedefficiency and stability. (AU)