Implementation of Pulsatile Flow on Microfilters for Efficient Cell Sorting

Cell sorting has been an important process in both clinical testing and medical diagnostics, and is used in many applications ranging from emergency trauma evaluation to cystic fibrosis checkups. Currently, efficient blood cell sorting needs to be done in a laboratory setting with dedicated machinery, and the process is expensive, labor intensive and time consuming. Multiple microfluidic solutions have been proposed to address these issues, including separation through hydrodynamics, magnetism, and dielectrophoresis. Although these devices alleviate some of the problems surrounding laboratory blood sorting, the chips remain complex, costly, and lacks the specificity needed to be used directly in a clinical setting. The purpose of this study is to investigate the effectiveness of a new cell sorting method: pulse width modulated periodic backflush in a dead-end filtration system. Dead-end filtration is a cheaper, simpler approach to cell sorting; particles are passed directly through a membrane filter which blocks larger particles while passing smaller ones. Dead-end filtration is easy to implement, and often has higher sorting efficiencies. The problem of particle throughput reduction due to clogging is alleviated by a periodic backflush mechanism that maintains high sorting efficiency while retaining particle throughput. We examine the impact of superimposing periodic backflush in a large fluidic system and create a prototype to validate this effect in a microfluidic environment. We use a mixture of staph epidermidis and lung epithelial cells to validate the application of backflush filtration in a clinical environment.Undergraduat

High efficiency phosphorescent organic light-emitting diodes using carbazole-type triplet exciton blocking layer

Device performances of green phosphorescent organic light-emitting diodes using 4,4 -N,N -dicarbazole biphenyl CBP and N,N -dicarbazolyl-3,5-benzene mCP as an exciton blocking layer were investigated. CBP and mCP were introduced between hole transport layer and emitting layer to block triplet exciton quenching and efficient hole transport to emitting layer. The efficiency of green devices could be improved by more than three times by using mCP exciton blocking layer

Lifetime improvement of green phosphorescent organic light-emitting diodes by charge confining device structure

Lifetime improvement of green phosphorescent organic light-emitting diodes by charge confinement inside an emitting layer was investigated. Excitons were confined within the emitting layer by using a charge confining structure with a high doping concentration at the center of the emitting layer. The lifetime of green devices could be improved by more than five times by confining the excitons at the center of the emitting layer

High-Efficiency Blue Organic Light-Emitting Diodes Using C60 as a Surface Modifier on Indium Tin Oxide

C60 was introduced as a modifier on indium tin oxide (ITO) and the effect of C60 modification on light-emitting efficiency of blue organic light-emitting didoes was investigated. Device performances of C60 modified devices were greatly dependent on ITO surface properties and C60 thickness. Power efficiency of blue devices was improved by 80% by C60 buffer layer on ITO because of low driving voltage and balanced electron-hole recombinatio

Efficient electron injection in organic light-emitting diodes using lithium quinolate/Ca/Al cathodes

Device performances of green devices with cathode structure of lithium quinolate Liq /Ca/Al were investigated and electron injection mechanism was studied using ultraviolet photoelectron spectroscopy. Power efficiency could be improved by 70% by using Liq/Ca/Al cathode structure due to efficient electron injection, and interfacial energy barrier lowering by Liq/Ca/Al metal cathode was observed

Molecular Design Approach Managing Molecular Orbital Superposition for High Efficiency without Color Shift in Thermally Activated Delayed Fluorescent Organic Lightâ Emitting Diodes

Molecular design principles of thermally activated delayed fluorescent (TADF) emitters having a high quantum efficiency and a color tuning capability was investigated by synthesizing three TADF emitters with donors at different positions of a benzonitrile acceptor. The position rendering a large overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) enhances the quantum efficiency of the TADF emitter. Regarding the orbital overlap, donor attachments at 2â and 6â positions of the benzonitrile were more beneficial than 3â and 5â substitutions. Moreover, an additional attachment of a weak donor at the 4â position further increased the quantum efficiency without decreasing the emission energy. Therefore, the molecular design strategy of substituting strong donors at the positions allowing a large molecular orbital overlap and an extra weak donor is a good approach to achieve both high quantum efficiency and a slightly increased emission energy.Overlap to emit: The substitution of strong donors at the positions rendering a large HOMOâ LUMO overlap and the addition of a weak donor constitute an effective design approach to realize TADF emitters having high efficiency.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147817/1/chem201805616-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147817/2/chem201805616.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147817/3/chem201805616_am.pd

Improvement in Power Efficiency in Organic Light Emitting Diodes Through Intermediate Mg:Ag Layer in LiF/Mg:Ag/Al Cathodes

Effects of Mg:Ag interlayer between LiF and Al on electron injection and device performances of organic light-emitting diodes OLEDs were investigated. Thickness of Mg:Ag layer was changed from 0 to 10 nm and the relationship between interlayer thickness and device performances was studied. Current density of OLEDs was increased due to efficient electron injection from cathode to organic layer by Mg:Ag interlayer. In addition, power efficiency of OLEDs was improved by more than 50% due to low driving voltage and high recombination efficiency and it showed a maximum value at a Mg:Ag thickness of 1.0 nm

Relationship Between Host Energy Levels and Device Performances of Phosphorescent Organic Light-Emitting Diodes with Triplet Mixed Host Emitting Structure

Green phosphorescent organic light-emitting diodes (PHOLEDs) with a triplet mixed host emitting layer were developed and device performances were studied by changing host materials in light-emitting layer. Power efficiency of green PHOLEDs could be improved from 12.7 to 29.1 lm/W by using triplet mixed host emitting layer. Combination of hole-transport-type host with good hole injection properties and electron-transport-type host with good electron injection properties was effective to get high efficiency in triplet mixed host devices

Nearly 100% Horizontal Dipole Orientation and Upconversion Efficiency in Blue Thermally Activated Delayed Fluorescent Emitters

The relationship between anisotropic orientation and molecular structure of thermally activated delayed fluorescent (TADF)‐based organic light emitting devices (OLEDs) is studied using TADF emitters with carbazole, biscarbazole, and triscarbazole donor units. The bicarbazole and triscarbazole donors are more effective than the carbazole donor in driving the anisotropic orientation of the TADF molecules. A near‐perfect in‐plane orientation of the TADF dipole moment is demonstrated using the triscarbazole donor. In addition, the triscarbazole donor based OLED shows high photoluminescence quantum yield and an upconversion efficiency close to 100%. As a consequence, an external quantum efficiency >30% is obtained.A systematic study correlating donor structure with horizontal dipole orientation of blue triscarbazole thermally activated delayed fluorescent (TADF) emitters shows an exceptionally high horizontal dipole orientation of 95%. The dipole orientation and high photoluminescence quantum yield result in an external quantum efficiency >30% in organic light‐emitting diodes employing these TADF emitters.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145231/1/adom201701340.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145231/2/adom201701340_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145231/3/adom201701340-sup-0001-S1.pd

Organic light emitting bistable memory device with high on/off ratio and low driving voltage

Organic light emitting bistable memory devices (OLEBDs) with a dual function of organic light emitting diodes and organic memory devices were developed by using 0.5 nm thick MoO3 as an interlayer between hole injection layer and hole transport layer. The hole transport unit with MoO3 interlayer played a role of a memory unit as well as a hole transport unit. High on/off ratio over 1000 was obtained at a reading voltage of 1 V and driving voltage was lowered by MoO3. In addition, two different luminances were obtained at the same driving voltage by changing writing voltage of OLEBDs