Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. ...Here we report the fabrication of 'polymer-metal hybrid electrodes' with high-performance properties, including a bending radius <1 mm, a visible-range transmittance>95% and a sheet resistance <10 Ω sq(-1). These features arise from a surface modification of the plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides.
A novel transfer‐printing method for high‐performance all‐plastic transparent electrodes is demonstrated. A solution process using H2SO4 not only dramatically enhances the electrical conductivity of ...poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) over 4000 S cm−1 but also chemically modifies its adhesion properties, thereby enabling expeditious “pick‐and‐place” transfer onto arbitrary surfaces using elastomeric stamps. Flexible and transparent optoelectronic devices with transferred PEDOT:PSS electrodes show superb performances.
Despite the recent unprecedented increase in the power conversion efficiencies (PCEs) of small‐area devices (≤0.1 cm2), the PCEs deteriorate drastically for PSCs of larger areas because of the ...incomplete film coverage caused by the dewetting of the hydrophilic perovskite precursor solutions on the hydrophobic organic charge‐transport layers (CTLs). Here, an innovative method of fabricating scalable PSCs on all types of organic CTLs is reported. By introducing an amphiphilic conjugated polyelectrolyte as an interfacial compatibilizer, fabricating uniform perovskite films on large‐area substrates (18.4 cm2) and PSCs with the total active area of 6 cm2 (1 cm2 × 6 unit cells) via a single‐turn solution process is successfully demonstrated. All of the unit cells exhibit highly uniform PCEs of 16.1 ± 0.9% (best PCE of 17%), which is the highest value for printable PSCs with a total active area larger than 1 cm2.
Large‐area planar perovskite solar cells (PSCs) are demonstrated by an innovative method using an amphiphilic conjugated polyelectrolyte as an interfacial compatibilizer between the hydrophobic organic charge‐transport layer and hydrophilic perovskite layer. Highly scalable PSCs with uniform perovskite films on a large‐area substrate (18.4 cm2) and with an active area of 1 cm2 exhibit stabilized power conversion efficiencies of 17%.
Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution ...with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives. A transparent titanium oxide (TiOx) layer separates and connects the front cell and the back cell. The TiOx layer serves as an electron transport and collecting layer for the first cell and as a stable foundation that enables the fabrication of the second cell to complete the tandem cell architecture. We use an inverted structure with the low band-gap polymer-fullerene composite as the charge-separating layer in the front cell and the high band-gap polymer composite as that in the back cell. Power-conversion efficiencies of more than 6% were achieved at illuminations of 200 milliwatts per square centimeter.
Crystalline poly(3,4‐ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) nanofibrils with an electrical conductivity of 4380 S cm‐1 are formed via a solution process using H2SO4. The ...concentrated H2SO4 treatment induces a significant structural rearrangement of the PEDOT:PSS via a charge‐separated transition mechanism, resulting in highly ordered and densely packed PEDOT:PSS nanofibrils. The PEDOT:PSS electrode shows a sheet resistance of 46 Ω sq‐1 with 90% optical transmittance.
“Top‐Down” nanophase reconstruction via a post‐additive soaking process is first presented with various BHJ binary composites. By simply rinsing as‐cast BHJ films with a solvent mixture containing a ...few traces of a nanophase‐control reagent such as 1,8‐diiodooctane, oversized fullerene‐rich clusters (>100 nm in diameter) in the BHJ film are instataneously disassembled and entirely reorganized into finely intermixed donor/acceptor nanophases (ca. 10 nm) with a 3D compositional homogeneity, without surface segregation.
Owing to the mixed electron/hole and ion transport in the aqueous environment, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based organic electrochemical transistor has been regarded as ...one of the most promising device platforms for bioelectronics. Nonetheless, there exist very few in-depth studies on how intrinsic channel material properties affect their performance and long-term stability in aqueous environments. Herein, we investigated the correlation among film microstructural crystallinity/composition, device performance, and aqueous stability in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) films. The highly organized anisotropic ordering in crystallized conducting polymer films led to remarkable device characteristics such as large transconductance (∼20 mS), extraordinary volumetric capacitance (113 F·cm
), and unprecedentedly high μC
value (∼490 F·cm
V
s
). Simultaneously, minimized poly(styrenesulfonate) residues in the crystallized film substantially afforded marginal film swelling and robust operational stability even after >20-day water immersion, >2000-time repeated on-off switching, or high-temperature/pressure sterilization. We expect that the present study will contribute to the development of long-term stable implantable bioelectronics for neural recording/stimulation.
Stretchable conductive materials have received great attention owing to their potential for realizing next-generation stretchable electronics. However, the simultaneous achievement of excellent ...mechanical stretchability and high electrical conductivity as well as cost-effective fabrication has been a significant challenge. Here, we report a highly stretchable and highly conducting polymer that was obtained by incorporating an ionic liquid. When 1-ethyl-3-methylimidazolium tetracyanoborate (EMIM TCB) was added to an aqueous conducting polymer solution of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), it was found that EMIM TCB acts not only as a secondary dopant but also as a plasticizer for PEDOT:PSS, resulting in a high conductivity of >1000 S cm–1 with stable performance at tensile strains up to 50% and even up to 180% in combination with the prestrained substrate technique. Consequently, by exploiting the additional benefits of high transparency and solution-processability of PEDOT:PSS, we were able to fabricate a highly stretchable, semitransparent, and wholly solution-processed alternating current electroluminescent device with unimpaired performance at 50% strain by using PEDOT:PSS/EMIM TCB composite films as both bottom and top electrodes.
A new series of protected isoindigo (ID) based solution processable donor-acceptor type of small molecules was synthesized. Tert-butoxycarbonyl (t-Boc) substituted isoindigo is used as the acceptor ...unit and oligothiophene derivatives as the donor units. Thermal decarboxylation of small molecules films at 200 °C eliminated the t-Boc side groups. The cleavage of the protecting group formed a variety of N–H …. .O=C hydrogen bonding across the lactam structures of the isoindigo. The molecular orientation during the thermal decarboxylation of ID-Boc to ID-H was examined using X-ray diffraction and atomic force microscopy. The H-bonding formation and its impact on the optical, thermal, electrochemical and ambipolar behavior were investigated.
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•H-bonding self-organized isoindigo based small molecules were synthesized and characterized.•During thermal deprotection, the targeted materials showed face on orientation in the solid state.•The hole mobility is dramatically a thousandfold increased after thermal deprotection.
The molecular ordering of aqueous conducting polymers is controlled using a rational method. By introducing various ionic liquids, which have designed electrostatic interactions to PEDOT:PSS ...solutions, the evolution of the molecular ordering of the PEDOT is manipulated. Consequently, highly ordered nanostructures are achieved with a reduced π–π stacking distance of ≈3.38 Å and, thus, a maximum σdc of ≈2100 S cm–1.
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