4 research outputs found
Fluorinated Alcohol-Processed NāType Organic Electrochemical Transistor with High Performance and Enhanced Stability
Tuning the film morphology and aggregated structure is
a vital
means to improve the performance of the mixed ionicāelectronic
conductors in organic electrochemical transistors (OECTs). Herein,
three fluorinated alcohols (FAs), including 2,2,2-trifluoroethanol
(TFE), 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), and perfluoro-tert-butanol (PFTB), were employed as the alternative solvents
for engineering the n-type small-molecule active layer gNR. Remarkedly, an impressive Ī¼C* of 5.12 F
Vā1 cmā1 sā1 and a normalized transconductance of 1.216 S cmā1 are achieved from the HFIP-fabricated gNR OECTs, which
is three times higher than that of chloroform. The operational stability
has been significantly enhanced by the FA-fabricated devices. Such
enhancements can be ascribed to the aggregation-induced structural
ordering by FAs during spin coating, which optimizes the microstructure
of the films for a better mixed ion and electron transport. These
results prove the huge research potential of FAs to improve OECT materialsā
processability, device performance, and stability, therefore promoting
practical bio-applications
A Thieno[2,3ā<i>b</i>]pyridine-Flanked Diketopyrrolopyrrole Polymer as an nāType Polymer Semiconductor for All-Polymer Solar Cells and Organic Field-Effect Transistors
A novel fused heterocycle-flanked
diketopyrrolopyrrole (DPP) monomer,
thienoĀ[2,3-<i>b</i>]Āpyridine diketopyrrolopyrrole (TPDPP),
was designed and synthesized. When copolymerized with 3,4-difluorothiophene
using Stille coupling polymerization, the new polymer pTPDPP-TF possesses
a highly planar conjugated polymer backbone due to the fused thienoĀ[2,3-<i>b</i>]Āpyridine flanking unit that effectively alleviates the
steric hindrance with both the central DPP core and the 3,4-difluorothiophene
repeat unit. This new polymer exhibits a high electron affinity (EA)
of ā4.1 eV and was successfully utilized as an n-type polymer
semiconductor for applications in organic field-effect transistors
(OFETs) and all polymer solar cells. A promising n-type charge carrier
mobility of 0.1 cm<sup>2</sup> V<sup>ā1</sup> s<sup>ā1</sup> was obtained in bottom-contact, top-gate OFETs, and a power conversion
efficiency (PCE) of 2.72% with a high open-circuit voltage (<i>V</i><sub>OC</sub>) of 1.04 V was achieved for all polymer solar
cells using PTB7-Th as the polymer donor
Amorphous Tin Oxide as a Low-Temperature-Processed Electron-Transport Layer for Organic and Hybrid Perovskite Solar Cells
Chemical
bath deposition (CBD) of tin oxide (SnO<sub>2</sub>) thin films as
an electron-transport layer (ETL) in a planar-heterojunction nāiāp
organohalide lead perovskite and organic bulk-heterojunction (BHJ)
solar cells is reported. The amorphous SnO<sub>2</sub> (a-SnO<sub>2</sub>) films are grown from a nontoxic aqueous bath of tin chloride
at a very low temperature (55 Ā°C) and do not require postannealing
treatment to work very effectively as an ETL in a planar-heterojunction
nāiāp organohalide lead perovskite or organic BHJ solar
cells, in lieu of the commonly used ETL materials titanium oxide (TiO<sub>2</sub>) and zinc oxide (ZnO), respectively. Ultraviolet photoelectron
spectroscopy measurements on the glass/indiumātin oxide (ITO)/SnO<sub>2</sub>/methylammonium lead iodide (MAPbI<sub>3</sub>)/2,2ā²,7,7ā²-tetrakisĀ(<i>N</i>,<i>N</i>-di-<i>p</i>-methoxyphenylamine)-9,9ā²-spirobifluorene
device stack indicate that extraction of photogenerated electrons
is facilitated by a perfect alignment of the conduction bands at the
SnO<sub>2</sub>/MAPbI<sub>3</sub> interface, while the deep valence
band of SnO<sub>2</sub> ensures strong hole-blocking properties. Despite
exhibiting very low electron mobility, the excellent interfacial energetics
combined with high transparency (<i>E</i><sub>gap,optical</sub> > 4 eV) and uniform substrate coverage make the a-SnO<sub>2</sub> ETL prepared by CBD an excellent candidate for the potentially low-cost
and large-scale fabrication of organohalide lead perovskite and organic
photovoltaics
Hybrid Rylene Arrays via Combination of Stille Coupling and CāH Transformation as High-Performance Electron Transport Materials
Hybrid rylene arrays have been prepared via a combination
of Stille
coupling and CāH transformation. The ability to extend the
Ļ system along the equatorial axis of rylenes not only leads
to broadened light absorption but also increases the electron affinity,
which can facilitate electron injection and transport with ambient
stability