Synergistic Effects of External Electric Field and Solvent Vapor Annealing with Different Polarities to Enhance β-Phase and Carrier Mobility of the Poly(9,9-dioctylfluorene) Films

Insights into the β‐phase of polyfluorene: characterization, regulation, and mechanism

“…48 F I G U R E 3 PL spectra of films before and after annealing and after annealing at different temperatures (A-C) 44 ; (D) Raman spectra of films after different methods of treatment. 27 The presence of β-phase in the films can also be determined by combining XRD and TEM to determine the lattice parameters. Chen et al 51 combined TEM and SAED to determine the lattice of α-phase PFO parameters (a = 2.56 nm, b = 2.34 nm, c = 3.32 nm).…”

“…Compared with the PFO active layer without β‐phase, the PFO film with low β‐phase (1.32%) showed an increase in hole mobility from 3 × 10 −5 to 5.5 × 10 −5 cm 2 V −1 s −1 , an increase in hole flux to 11 times of the original, and an increase in electron current from 1.9 × 10 −7 to 6.2 × 10 −7 A cm −3 18 . In addition, there are significant differences in luminescence behavior between the two, with devices with low levels of β‐phase exhibiting a 300% increase in luminescence efficiency (from 1.1 to 3.3%, or from 1.3 to 3.9 cd A −1 ) and an increase in maximum luminance from 12,600 to 34,300 cd m −2 , while producing purer and more intense blue light emission in the electroluminescent device; the PFO films with high content of β‐phase (34.9%) also increased the hole mobility by an order of magnitude 27 …”

“…18 In addition, there are significant differences in luminescence behavior between the two, with devices with low levels of β-phase exhibiting a 300% increase in luminescence efficiency (from 1.1 to 3.3%, or from 1.3 to 3.9 cd A À1 ) and an increase in maximum luminance from 12,600 to 34,300 cd m À2 , while producing purer and more intense blue light emission in the electroluminescent device; the PFO films with high content of β-phase (34.9%) also increased the hole mobility by an order of magnitude. 27 Given the important influence of the β-phase on the optoelectronic properties, it is particularly important to control its content. However, not all PFO can form β conformation.…”

Study of the Dynamic Process of Enhancing the Stability of Conjugated Polymer Solutions and Films Induced by an External Electric Field

“…Commonly used external fields include temperature field, solvent field, force field, external electric field, etc. ; among them, studies on the effect of the temperature field and solvent field on conjugated polymers have been reported, − while the manipulation of the conjugated polymer solution behavior under the action of an external electric field is rarely reported due to its certain difficulties . As we know, the external electric field is a directional field, which can induce the oriented arrangement of conjugated polymer molecular chains − and then make the molecular chains self-assemble to form larger aggregation or ordered structures.…”

“…At present, the studies on MEH-PPV and other conjugated polymers have been focusing on the new material synthesis with high efficiency and device fabrication; , however, the research on the solution behavior and stability is limited by research methods and means − and rarely reported. The choice of external field induction to manipulate the conjugated polymer solution behavior (chain conformations, topological structure, fractal dimension, stacking density of chain aggregation, etc.)…”