Orientation of Phenylphosphonic Acid Self-Assembled Monolayers on a Transparent Conductive Oxide: A Combined NEXAFS, PM-IRRAS, and DFT Study

Self-assembled monolayers (SAMs) of dipolar phosphonic acids can tailor the interface between organic semiconductors and transparent conductive oxides. When used in optoelectronic devices such as organic light emitting diodes and solar cells, these SAMs can increase current density and photovoltaic performance. The molecular ordering and conformation adopted by the SAMs determine properties such as work function and wettability at these critical interfaces. We combine angle-dependent near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) to determine the molecular orientations of a model phenylphosphonic acid on indium zinc oxide, and correlate the resulting values with density functional theory (DFT). We find that the SAMs are surprisingly well-oriented, with the phenyl ring adopting a well-defined tilt angle of 12–16° from the surface normal. We find quantitative agreement between the two experimental techniques and density functional theory calculations. These results not only provide a detailed picture of the molecular structure of a technologically important class of SAMs, but also resolve a long-standing ambiguity regarding the vibrational-mode assignments for phosphonic acids on oxide surfaces, thus improving the utility of PM-IRRAS for future studies

Urban Students’ Perceptions of Teachers: Views of Students in General, Special, and Honors Education

Students’ satisfaction with school experiences has been linked to their sense of belongingness, connection to school, and achievement. Though the extant research addresses students’ perceptions of school climate and sense of belonging, there is a paucity of research about students’ views of teacher–student interactions. Five hundred and seventy-seven students from one ethnically and academically diverse urban high school were surveyed and interviewed about the nature of teacher talk with students. Findings from this mixed-methods investigation indicate students from general, special, and honors programs experience a wide range of interactions based on academic services received, gender, and ethnicity. More frequent perceived punitive feedback was reported by all students in special education as well as males in general and honors education programs, while Hispanic students indicated a greater frequency of perceived supportive feedback. Findings also reflect a wide range of attitudes and feelings about teachers, the educational system, and learning