Charge Transport in MAPbI(3) Pellets across the Tetragonal-to-Cubic Phase Transition: The Role of Grain Boundaries from Structural, Electrical, and Optical Characterizations

Autor(es)

Sombrio, G. ^[1] ; Zhang, Z. ^[2] ; Bonadio, A. ^[1] ; de Oliveira, L. S. ^[1] ; de Queiroz, T. B. ^[1] ; Ferreira, F. F. ^[1] ; Janotti, A. ^[2] ; Souza, J. A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Santo Andre, SP - Brazil

^[2] Univ Delaware, Dept Mat Sci & Engn, Newark, DE 19716 - USA

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 124, n. 20, p. 10793-10803, MAY 21 2020.
• Citações Web of Science: 0

Resumo

Methylammonium lead iodide (MAPbI(3)) is a very promising semiconducting material for photovoltaic applications. Despite extensive research and tremendous progress, basic charge transport properties are still being debated. Combining first-principles calculations and macroscopic and local measurements, we have investigated the structural, optical, thermal, and electrical transport (ac/dc) properties of MAPbI(3) hot-pressed pellets through the tetragonal-to-cubic phase transition. Thermal analysis and X-ray diffraction experiments confirm the tetragonal-to-cubic phase change around T-S = 56 degrees C, which is often close to the working temperature of photovoltaic devices. The ac/dc electrical resistivities of the tetragonal phase indicate a metallic-like behavior as a function of temperature followed by an abrupt decrease in the cubic phase just above T-S. In contrast to the abrupt changes observed in the electrical properties, the bandgap energy is barely affected across the phase transition. Similarly, local measurements obtained by means of nuclear magnetic resonance confirm a continuous variation in the lattice parameters and site symmetry (Pb-207 and I-127) across the structural phase transition. Density functional theory calculations combined with electrical characterizations indicate that iodine and/or unintentionally incorporated hydrogen interstitials influence decisively the charge transport activation energy in the cubic phase. In light of these findings, the unusual electrical resistivity behavior across the phase transition is discussed taking the grain boundary effects into consideration. (AU)

• Processo FAPESP: 19/01785-8 - Síntese e caracterização de filmes de perovskitas CH3NH3PbX3
• Beneficiário: Guilherme Sombrio
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 17/02317-2 - Interfaces em materiais: propriedades eletrônicas, magnéticas, estruturais e de transporte
• Beneficiário: Adalberto Fazzio
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 18/15682-3 - Síntese e caracterização das propriedades físicas de materiais semicondutores micro/nano estruturados
• Beneficiário: José Antonio Souza
• Modalidade de apoio: Auxílio à Pesquisa - Regular