Publications by authors named "Nara Cho"

Child physical abuse is a common cause of pediatric morbidity and mortality. Up to half of all children presenting with abusive injuries have a history of a prior suspicious injury, suggesting a pattern of repeated physical abuse. Medical providers are responsible for identifying children with suspicious injuries, completing mandated reporting to child protective services for investigation, and screening for occult injuries and underlying medical conditions that can predispose to injuries.

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The symmetrical planar star-shaped organic semiconductor DMM-TPA-[DTS(BTTh(3))](3) with fused TPA core donor and three branch motifs, DTS(BTTh(3)), exhibited efficient p-type semiconducting performance in solution-processed SMOSCs and OFETs compared to the tilted star-shaped TPA-[DTS(BTTh(3))](3); a noteworthy PCE value of 4.16% was observed, with a hole mobility and on/off ratio of 7.6 × 10(-3) cm(2) V(-1) s(-1) and 5 × 10(6), respectively.

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New electron-rich anthracene derivatives containing triarylamine hole stabilizers, 2,6-bis[5,5'-bis(N,N'-diphenylaniline)-2,2'-bithiophen-5-yl]-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-TPA) and 2,6-bis(5,5'-bis{4-[bis(9,9-dimethyl-9H-fluoren-2-yl)amino]phenyl}-2,2'-bithiophen-5-yl)-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-bisDMFA), linked with π-conjugated bithiophene bridges, were synthesized and their photovoltaic characteristics were investigated in solution-processed small-molecule organic solar cells (SMOSCs). These new materials exhibited superior intramolecular charge transfer from triarylamine to anthracene, leading to a more electron-rich anthracene core that facilitated electron transfer into phenyl-C(61)-butyric acid methyl ester. Compared with TIPSAntBT and triarylamine, these materials show a threefold improvement in hole-transporting properties and better photovoltaic performance in solution-processed SMOSCs, with the best power conversion efficiency being 2.

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A facile new protocol for the synthesis of iodinated derivatives of fluorinated benzothiadiazoles is demonstrated for the production of p-type semiconducting materials. The newly synthesized small-molecule compounds bis[TPA-diTh]-MonoF-BT and bis[TPA-diTh]-DiF-BT exhibited a power conversion efficiency of 2.95% and a high open-circuit voltage of 0.

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A new type of organic sensitizers incorporating a planar amine unit have been synthesized and demonstrated to be a highly efficient sensitizers, showing evidence of lateral interactions on the TiO(2) surface. Under standard global air mass 1.5 solar conditions, the JK-98 sensitized cell gave a short circuit photocurrent density (J(sc)) of 16.

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We have synthesized and characterized four organic dyes (H1-H4) based on a 3,6-disubstituted carbazole donor as sensitizers in dye-sensitized solar cells. These dyes have high molar extinction coefficients and energy levels suitable for electron transfer from an electrolyte to nanocrystalline TiO(2) particles. Under standard air mass 1.

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Annulated thiophene perylene bisimides and their triphenyl-amine based oligomers have been synthesized. One of the oligomers FPTTPA has been demonstrated to be an efficient electron donor in bulk heterojunction (BHJ) organic solar cells, giving a power conversion efficiency of 1.42%.

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A new series of stable, unsymmetrical squaraine near-IR sensitizers (JK-216 and JK-217), which are assembled using both thiophenyl pyrrolyl and indolium groups, exhibit a panchromatic light harvesting up to 780 nm. The JK-216 based cell exhibited a record efficiency of 6.29% for near-IR DSSCs.

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