Impact of Solvent Vapor Annealing on the Morphology and Photophysics of Molecular Semiconductor Thin Films

Abstract

The effect of solvent vapor annealing on the fluorescence properties and morphology of titanyl phthalocyanine/ perylene phenethylimide thin-film molecular semiconductor bilayers (TiOPc/PPEI) is investigated. A combination of atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM) is used in conjunction with bulk absorption and fluorescence measurements to correlate the morphological and photophysical properties of these bilayer systems. AFM data show that treatment of the vacuum-deposited amorphous PPEI and TiOPc/PPEI films results in the crystalline transformation of these materials and severely alters the contact between the TiOPc and PPEI layers. AFM data show extended solvent vapor annealing produces void spaces in the TiOPc coverage on the order of several hundred nanometers. Steady-state fluorescence intensity and fluorescence lifetime measurements are used as a measure of charge-transfer quenching efficiencies. Very efficient charge-transfer quenching is observed when amorphous layers of TiOPc are deposited onto PPEI resulting from uniform contact between the layers. Extended annealing results in decreased charge-transfer quenching efficiencies as a result of widely dispersed, localized interfacial contact points.

Surface-enhanced Raman scattering and SERRS imaging of phthalocyanine mixed films

“…Phthalocyanine and perylene tetracarboxylic acid (PTCD) materials are being tested in thin film devices as thin film molecular semiconductor bilayers [1] or for forming organic photovoltaic cells [2]. Several templates for device manufacture have been presented throughout the past decade.…”

“…Hiramoto et al [5] reported the first threelayered organic solar cell with a photoactive interlayer of co-deposited metal-free phthalocyanine and a perylene tetracarboxylic derivative (Me-PTC). More recently, characterization of molecular thin films of perylene and phthalocyanine derivatives has been the main focus of research [1,[6][7][8][9][10]. Here we present the first study of codeposited MPc/PTCD mixed films using the methods of surface-enhanced vibrational spectroscopy.…”

Thin-Layer Matrix Sublimation with Vapor-Sorption Induced Co-Crystallization for Sensitive and Reproducible SAMDI-TOF MS Analysis of Protein Biosensors

“…We hypothesized that vapors from organic solvents would promote the crystalline transformation similar to methods used in materials research [40,41]. To test this, five polar solvents with varying CHCA solubility were evaluated for suitability for VIC and downstream SAMDI MS (Table S1).…”

Achieving Perpendicular Alignment of Rigid Polythiophene Backbones to the Substrate by Using Solvent‐Vapor Treatment

“…From an application perspective, we employ here a solventvapor treatment or "solvent annealing", [11][12][13][14] starting from a spin-coated poly(3-butylthiophene) (P3BT) film, to carry out the transformation of regioregular P3BT backbones from parallel to perpendicular orientation with respect to the substrate, together with the crystallographic transition from typical Form I to Form II. As illustrated by the wide-angle X-ray diffraction (WAXD) pattern shown in Figure 1, the reflection peak from the (100) Miller plane of Form I, which is around 2h = 7.2°(d-spacing 12.3 Å) in a WAXD profile, gradually disappears upon exposure to carbon disulfide vapor, accompanied by the appearance of the (100) reflection of Form II at 2h ≈ 9.2°(d-spacing 9.6 Å).…”