Probing Device Degradation and Electric Fields in Polymeric Field-Effect Transistors by SFG Vibrational Spectroscopy

Autor(es)

Motti, Silvia G. ^{[1, 2]} ; Cardoso, Lilian S. ^[1] ; Gomes, Douglas J. C. ^[1] ; Faria, Roberto M. ^[1] ; Miranda, Paulo B. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Phys Inst, CP 369, BR-13560970 Sao Carlos, SP - Brazil

^[2] Ist Italiano Tecnol, Ctr Nano Cience & Technol Polimi, Via Pascoli 70-3, I-20133 Milan - Italy

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 122, n. 19, p. 10450-10458, MAY 17 2018.
• Citações Web of Science: 1

Resumo

There is great interest on the study of the semiconductor/dielectric interface of organic field-effect transistors (OFETs), where a conducting channel is formed. Here, we use the interface selectivity, chemical sensitivity, and field-induced enhancement of sum-frequency generation (SFG) vibrational spectroscopy to probe interfacial molecular ordering and degradation processes in poly-3-hexylthiophene (P3HT) OFETs and also the electric field within their dielectric layer (poly(methyl methacrylate), PMMA). P3HT active layers fabricated by the Langmuir-Schaefer method are more orientationally ordered than spin-coated films. Upon electrical degradation of the device in ambient conditions, no noticeable changes were detected in the SFG spectra of the semiconductor/dielectric interface because the sensitivity of our experiment was not enough to detect degraded polymer chains due to loss of SFG electronic resonance enhancement. Perhaps for the same reason, we were also not able to detect any significant changes in the SFG spectra of the P3HT/dielectric interface upon charge accumulation induced by the gate bias. However, we found that upon polarizing the device, PMMA vibrational bands appeared due to field-induced reorientation of its polar groups. Therefore, SFG spectroscopy can be used to probe the electric field within the organic dielectric, including its sign, bringing the possibility of a complete device characterization by nonlinear spectroscopy/microscopy, mapping out the electric field both within the semiconductor and dielectric layers of the OFETs. (AU)

• Processo FAPESP: 14/50869-6 - INCT 2014: em Eletrônica Orgânica INEO
• Beneficiário: Roberto Mendonça Faria
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/07328-1 - Estudo de interfaces em dispositivos emissores de luz poliméricos (PLEDs) por espectroscopia SFG
• Beneficiário: Douglas José Correia Gomes
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 15/24908-7 - Estudos da influência de atmosfera de oxigênio sobre o transporte eletrônico em dispositivos fotovoltaicos orgânicos
• Beneficiário: Roberto Mendonça Faria
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/01595-0 - Estudo de interfaces em dispositivos optoeletrônicos poliméricos por espectroscopia SFG
• Beneficiário: Roberto Mendonça Faria
• Modalidade de apoio: Auxílio à Pesquisa - Regular