12 research outputs found
EMSL Pore Scale Modeling Challenge/Workshop
Report covers the background for the workshop, objectives, important research directions, necessary capabilities and overall recommendations
Osmium Replica of Mesoporous Silicate MCM-48:Â Efficient and Reusable Catalyst for Oxidative Cleavage and Dihydroxylation Reactions
Large-Area Nonfullerene Organic Solar Cell Modules Fabricated by a Temperature-Independent Printing Method
Long-Term Stable Recombination Layer for Tandem Polymer Solar Cells Using Self-Doped Conducting Polymers
Recently, the most efficient tandem
polymer solar cells (PSCs) have used polyÂ(3,4-ethyleneÂdioxythiophene):polyÂ(styreneÂsulfonate)
(PEDOT:PSS) as a p-type component of recombination layer (RL). However,
its undesirable acidic nature, originating from insulating PSS, of
PEDOT:PSS drastically reduces the lifetime of PSCs. Here, we demonstrate
the efficient and stable tandem PSCs by introducing acid-free self-doped
conducting polymer (SCP), combined with zinc oxide nanoparticles (ZnO
NPs), as RL for PEDOT:PSS-free tandem PSCs. Moreover, we introduce
an innovative and versatile nanocomposite system containing photoactive
and p-type conjugated polyelectrolyte (p-CPE) into the tandem fabrication
of an ideal self-organized recombination layer. In our new RL, highly
conductive SCP facilitates charge transport and recombination process,
and p-CPE helps to achieve nearly loss-free charge collection by increasing
effective work function of indium tin oxide (ITO) and SCP. Because
of the synergistic effect of extremely low electrical resistance,
ohmic contact, and pH neutrality, tandem devices with our novel RL
performed well, exhibiting a high power conversion efficiency of 10.2%
and a prolonged lifetime. These findings provide a new insight for
strategic design of RLs using SCPs to achieve efficient and stable
tandem PSCs and enable us to review and extend the usefulness of SCPs
in various electronics research fields
In Situ Doping of the PEDOT Top Electrode for All-Solution-Processed Semitransparent Organic Solar Cells
The development of an ideal solution-processable transparent
electrode
has been a challenge in the field of all-solution-processed semitransparent
organic solar cells (ST-OSCs). We present a novel poly(3,4-ethylenedioxythiophene):polystyrenesulfonate
(PEDOT:PSS) top electrode for all-solution-processed ST-OSCs through
in situ doping of PEDOT:PSS. A strongly polarized long perfluoroalkyl
(n = 8) chain-anchored sulfonic acid effectively
eliminates insulating PSS and spontaneously crystallizes PEDOT at
room temperature, leading to outstanding electrical properties and
transparency of PEDOT top electrodes. Doped PEDOT-based ST-OSCs yield
a high power conversion efficiency of 10.9% while providing an average
visible transmittance of 26.0% in the visible range. Moreover, the
strong infrared reflectivity of PEDOT enables ST-OSCs to reject 62.6%
of the heat emitted by sunlight (76.7% from infrared radiation), outperforming
the thermal insulation capability of commercial tint films. This light
management approach using PEDOT enables ST-OSCs to simultaneously
provide energy generation and energy savings, making it the first
discovery toward sustainable energy in buildings
Self-assembly of interfacial and photoactive layers via one-step solution processing for efficient inverted organic solar cells
Direct Observation of Confinement Effects of Semiconducting Polymers in Polymer Blend Electronic Systems
Abstract The advent of special types of polymeric semiconductors, known as âpolymer blends,â presents new opportunities for the development of nextâgeneration electronics based on these semiconductors' versatile functionalities in device applications. Although these polymer blends contain semiconducting polymers (SPs) mixed with a considerably high content of insulating polymers, few of these blends unexpectedly yield much higher charge carrier mobilities than those of pure SPs. However, the origin of such an enhancement has remained unclear owing to a lack of cases exhibiting definite improvements in charge carrier mobility, and the limited knowledge concerning the underlying mechanism thereof. In this study, the morphological changes and internal nanostructures of polymer blends based on various SP types with different intermolecular interactions in an insulating polystyrene matrix are investigated. Through this investigation, the physical confinement of donorâacceptor type SP chains in a continuous nanoscale network structure surrounded by polystyrenes is shown to induce structural ordering with more straight edgeâon stacked SP chains. Hereby, highâperformance and transparent organic fieldâeffect transistors with a hole mobility of â5.4 cm2 Vâ1 sâ1 and an average transmittance exceeding 72% in the visible range are achieved
Overcoming the Interfacial Photocatalytic Degradation of Nonfullerene Acceptor-Based Organic Photovoltaics by Introducing a UV-A-Insensitive Titanium Suboxide Layer
Although recent dramatic advances in power conversion
efficiencies
(PCEs) have resulted in values over 19%, the poor photostability of
organic photovoltaics (OPVs) has been a serious bottleneck to their
commercialization. The photocatalytic effect, which is caused by incident
ultraviolet-A (UV-A, 320â400 nm) light in the most commonly
used zinc oxide (ZnOX) electron transport
layer (ETL), significantly deteriorates the photostability of OPVs.
In this work, we develop a new and facile method to enhance the photostability
of nonfullerene acceptor-based OPVs by introducing UV-A-insensitive
titanium suboxide (TiOX) ETL. Through
an in-depth analysis of mass information at the interface between
the ETL and photoactive layer, we confirm that the UV-A-insensitive
TiOX suppresses the photocatalytic effect.
The resulting device employing the TiOX ETL shows excellent photostability, obtaining 80% of the initial
PCE for up to 200 h under 1 sun illumination, which is 10 times longer
than that of the conventional ZnOX system
(19 h)