Intrachain charge transport is unique to conjugated polymers distinct from inorganic and small molecular semiconductors and is key to achieving high-performance organic electronics. Polymer backbone planarity and thin film morphology sensitively modulate intrachain charge transport. However, simple, generic nonsynthetic approaches for tuning backbone planarity and the ensuing multiscale assembly process do not exist. We first demonstrate that printing flow is capable of planarizing the originally twisted polymer backbone to substantially increase the conjugation length. This conformation change leads to a marked morphological transition from chiral, twinned domains to achiral, highly aligned morphology, hence a fourfold increase in charge carrier mobilities. We found a surprising mechanism that flow extinguishes a lyotropic twist-bend mesophase upon backbone planarization, leading to the observed morphology and electronic structure transitions.
Charge transport in conjugated polymer semiconductors has traditionally been thought to be limited to a low-mobility regime by pronounced energetic disorder. Much progress has recently been made in advancing carrier mobilities in field-effect transistors through developing low-disorder conjugated polymers. However, in diodes these polymers have to date not shown much improved mobilities, presumably reflecting the fact that in diodes lower carrier concentrations are available to fill up residual tail states in the density of states. Here, we show that the bulk charge transport in low-disorder polymers is limited by water-induced trap states and that their concentration can be dramatically reduced through incorporating small molecular additives into the polymer film. Upon incorporation of the additives we achieve space-charge limited current characteristics that resemble molecular single crystals such as rubrene with high, trap-free SCLC mobilities up to 0.2 cm 2 /Vs and a width of the residual tail state distribution comparable to k B T .
No abstract
The viscosities of CaO-SiO 2 -Al 2 O 3 -MgO-FeO slag were measured under conditions of C/Sϭ1.35-1.45, 10-18 mass% Al 2 O 3 , 3.5-10 mass% MgO and 5 mass% FeO. The bosh slag with 10 mass% Al 2 O 3 content had the lowest melting temperature and the widest solid-liquid coexisting region at about 5 mass% MgO, while in case of 14 mass% Al 2 O 3 , an increase in a MgO content from about 3.5 to 10 mass% raised the melting point of bosh slag. The viscosity of bosh slag also exhibited a minimum value at about 7 mass% MgO at temperatures above 1 723 K. However, it was not significantly changed with varying MgO content. On the hand, with increasing Al 2 O 3 content, the viscosity of bosh slag increased at a fixed C/S and MgO content. Based on the melting temperature and the behavior of viscosity at a fixed temperature, it could be proposed that the MgO and Al 2 O 3 contents in bosh slag should be maintained around 5 and 10 mass%, respectively, for high pulverized-coal ratio (PCR) and low slag volume operations in blast furnace.KEY WORDS: viscosity; bosh slag; blast furnace; slag volume reduction; slag structure; FT-IR. 100 rpm) were employed in 1 773 K to ensure that viscosity values were independent of rotation speed. All measurements were performed with cooling and holding temperature. The holding time for reaching equilibrium state was more than 30 min at each experimental temperature. A metal flange was utilized to fill the gap between the viscometer and the mullite reaction tube, and an Ar gas (0.4 L/min) was flown into the reaction chamber. After viscosity measurements were completed, the slag samples were reheated up to 1 773 K, and held for more than 3 h. Then, the slag sample was quenched to analyze slag composition and to measure the infrared spectra of the slag. According to the composition analysis of post-measurement slag using X-ray Fluorescence (Bruker-SRS3400), there was no significant change in any component of slags (less than 1 %).In order to confirm the reproducibility of viscosity values, some experiments for the same composition were carried out three times. The results show that differences between measurements were lower than 0.2 dPa · s (less than 0.5 %). Infrared Spectra MeasurementThe structure of the investigated slags was analyzed by FT-IR spectroscopy (JASCO, FT/IR-300 E). FT-IR trans- ISIJ International, Vol. 44 (2004) mitting spectra were recorded in the 4 000 -400 cm Ϫ1 range using a spectrometer equipped with a KBr (deuterated triglycine sulfate with potassium bromide windows) detector. A spectral resolution of 4 cm Ϫ1 was chosen. Each 2.0 mg sample was mixed with 200 mg of KBr in an agate mortar, and then pressed into 13 mm diameter pellets. The spectrum for each sample represents an average of 20 scans, which were each normalized to the spectrum of the blank KBr pellets. The FT-IR spectra were analyzed by computer software. Results and DiscussionIn the present study, the effects of MgO and Al 2 O 3 contents on the viscosities of the CaO-SiO 2 -Al 2 O 3 -MgO-FeO slags were investigate...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.