High Detectivity Near Infrared Organic Photodetectors Using an Asymmetric Non-Fullerene Acceptor for Optimal Nanomorphology and Suppressed Dark Current.

Recently, the development of non-fullerene acceptors (NFAs) for near-infrared (NIR) organic photodetectors (OPDs) has attracted great interest due to their excellent NIR light absorption properties. Herein, we developed NFAs by substituting an electron-donating moiety (branched alkoxy thiophene (BAT)) asymmetrically (YOR1) and symmetrically (YOR2) for the Y6 framework. YOR1 exhibited nanoscale phase separation in a film blended with PTB7-Th. Moreover, substituting the BAT unit effectively extended the absorption wavelengths of YOR1 over 1000 nm by efficient intramolecular charge transfer and extension of the conjugation length. Consequently, YOR1-OPD exhibited significantly reduced dark current and improved responsivity by simultaneously satisfying optimal nanomorphology and significant suppression of charge recombination, resulting in 1.98 × 1013 and 3.38 × 1012 Jones specific detectivity at 950 and 1000 nm, respectively. Moreover, we successfully demonstrated the application of YOR1-OPD in highly sensitive photoplethysmography sensors using NIR light. This study suggests a strategic approach for boosting the overall performance of NIR OPDs targeting a 1000 nm light signal using an all-in-one (optimal morphology, suppressed dark current, and extended NIR absorption wavelength) NFA.

Highly Sensitive and Durable Organic Photodiodes Based on Long-Term Storable NiOx Nanoparticles.

Organic optoelectronic devices that can be fabricated at low cost have attracted considerable attention because they can absorb light over a wide frequency range and have high conversion efficiency, as well as being lightweight and flexible. Moreover, their performance can be significantly affected by the choice of the charge-selective interlayer material. Nonstoichiometric nickel oxide (NiOx) is an excellent material for the hole-transporting layer (HTL) of organic optoelectronic devices because of the good alignment of its valence band position with the highest occupied molecular orbital level of many p-type polymers. Herein, we report a simple low-temperature process for the synthesis of NiOx nanoparticles (NPs) that can be well dispersed in solution for long-term storage and easily used to form thin NiOx NP layers. NiOx NP-based organic photodiode (OPD) devices demonstrated high specific detectivity (D*) values of 1012-1013 jones under various light intensities and negative biases. The D* value of the NiOx NP-based OPD device was 4 times higher than that of a conventional poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based device, an enhancement that originated mainly from the 16 times decreased leakage current. The NiOx NP-based OPD device demonstrated better reliability over a wide range of light intensities and operational biases in comparison to a device with a conventional sol-gel-processed NiOx film. More importantly, the NiOx NP-based OPD showed long-term device stability superior to those of the PEDOT:PSS and sol-gel-processed NiOx-based devices. We highlight that our low-temperature solution-processable NiOx NP-based HTL could become a crucial component in the fabrication of stable high-performance OPDs.

Enhanced Static and Dynamic Properties of Highly Miscible Fullerene-Free Green-Selective Organic Photodetectors.

We developed p-n junction organic photodetectors (OPDs) composed of a polymer donor and a nonfullerene acceptor (NFA) to increase both the responsivity (R) and detectivity (D*) while maintaining a narrow wavelength selectivity. The selection of the polymer donor and NFA with similar green (G) absorption is important for achieving G-wavelength selectivity in these OPDs, which differentiates them from current fullerene-based OPDs and NFA-based panchromatic absorption OPDs. In addition, mixing the polymer donor and asymmetric NFA was efficient toward increasing the miscibility and decreasing the interfacial energy difference of the blended films, resulting in the formation of a uniform and well-mixed nanomorphology in the photoconductive layer. Two-dimensional (2D) grazing incidence X-ray diffraction and Fourier-transform infrared spectroscopy revealed that the lamellar ordering of the polymer donor was enhanced in the blend film prepared with an asymmetric NFA, whereas the aggregation of a symmetric NFA in the blend films did not increase the lamellar ordering of the polymer donor. Consequently, we achieved an R value of 0.31 A/W and D* value of 2.0 × 1013 Jones with a full width at half-maximum value of 230 nm at -2 V and fast response time of 27 µs without any external bias in the asymmetric NFA-based OPDs. The enhancement in the lamellar ordering and miscibility of the blended films are crucial toward increasing the static and dynamic properties of OPDs.

Recent progress of ultra-narrow-bandgap polymer donors for NIR-absorbing organic solar cells.

Solution-processed near-infrared (NIR)-absorbing organic solar cells (OSCs) have been explored worldwide because of their potential as donor:acceptor bulk heterojunction (BHJ) blends. In addition, NIR-absorbing OSCs have attracted attention as high specialty equipment in next-generation optoelectronic devices, such as semitransparent solar cells and NIR photodetectors, owing to their feasibility for real-time commercial application in industry. With the introduction of NIR-absorbing non-fullerene acceptors (NFAs), the value of OSCs has been increasing while organic donor materials capable of absorbing light in the NIR region have not been actively studied yet compared to NIR-absorbing acceptor materials. Therefore, we present an overall understanding of NIR donors.

Orthogonal Printable Reduced Graphene Oxide 2D Materials as Hole Transport Layers for High-Performance Inverted Polymer Solar Cells: Sheet Size Effect on Photovoltaic Properties.

Creating an orthogonal printable hole-transporting layer (HTL) without damaging the underlying layer is still a major challenge in fabricating large-area printed inverted polymer solar cells (PSCs). In this study, we prepared orthogonal-processable fluorine-functionalized reduced graphene oxide (FrGO) series with various two-dimensional sheet sizes such as large-sized FrGO (1.1 µm), medium-sized FrGO (0.7 µm), and small-sized FrGO (0.3 µm) and systematically investigated the size effect of FrGOs on the hole transport properties of PSCs. The FrGOs exhibit highly stable dispersion without change over 90 days in 2-propanol solvent, indicating very high dispersion stability. Decreasing the sheet size of FrGOs enhanced hole-transporting properties, resulting in power conversion efficiencies (PCEs) of 9.27 and 9.02% for PTB7-Th:EH-IDTBR- and PTB7-Th:PC71BM-based PSCs, respectively. Compared to devices with solution-processed poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), a 14% enhancement of PCEs was achieved. Interestingly, the PCEs of devices with the smallest FrGO sheet are higher than the PCE of 8.77% of a device with vacuum-deposited MoO3. The enhancement in the performance of PSCs is attributed to the enhanced charge collection efficiency, decreased leakage current, internal resistance, and minimized charge recombination. Finally, small-sized FrGO HTLs were successfully coated on the photoactive layer using the spray coating method, and they also exhibited PCEs of 9.22 and 13.26% for PTB7-Th:EH-IDTBR- and PM6:Y6-based inverted PSCs, respectively.

Composite Interlayer Consisting of Alcohol-Soluble Polyfluorene and Carbon Nanotubes for Efficient Polymer Solar Cells.

We report the synthesis of composite interlayers using alcohol-soluble polyfluorene (ASP)-wrapped single-walled carbon nanotubes (SWNTs) and their application as electron-transport layers for efficient organic solar cells. The ASP enables the individual dispersion of SWNTs in solution. The ASP-wrapped SWNT solutions are stable for 54 days without any aggregation or precipitation, indicating their very high dispersion stability. Using the ASP-wrapped SWNTs as a cathode interlayer on zinc oxide nanoparticles (ZnO NPs), a power conversion efficiency of 9.45% is obtained in PTB7-th:PC71BM-based organic solar cells, which is mainly attributed to the improvement in the short circuit current. Performance enhancements of 18 and 17% are achieved compared to those of pure ZnO NPs and ASP on ZnO NPs, respectively. In addition, the composite interlayer is applied to non-fullerene-based photovoltaics with PM6:Y6, resulting in a power conversion efficiency of up to 14.37%. The type of SWNT (e.g., in terms of diameter range and length) is not critical to the improvement in the charge-transport properties. A low density of SWNTs in the film (∼1 SWNTs/µm2 for ASP-wrapped SWNTs) has a significant influence on the charge transport in solar cells. The improvement in the performance of the solar cell is attributed to the increased internal quantum efficiency, balanced mobility between electrons and holes, and minimized charge recombination.

Comparison of Optical and Electrical Properties of Different Hole-Transporting Materials for Solution-Processable Organic Light-Emitting Diodes.

Achieving well-defined multilayer structure is a key to improve device performance of organic light-emitting diodes (OLEDs), especially in solution-processed OLEDs. Use of cross-linkable hole-transporting materials (HTMs) is therefore gaining much attention to achieve such multilayer structures. One of representative solution-processable HTM is TFB, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)], but it does not have any cross-linkable units in its chemical structures. In this work, we performed basic physical characterization of a new cross-linkable HTM, HL-X026, and we also investigated its OLED characteristics. Actual solvent resistance by varying the thermal curing temperatures was measured. The thermally cross-linkable HL-X026 showed better device performances than simple TFB with higher luminance and efficiencies.

High-Performance Near-Infrared Absorbing n-Type Porphyrin Acceptor for Organic Solar Cells.

While the outstanding charge transport and sunlight-harvesting properties of porphyrin molecules are highly attractive as active materials for organic photovoltaic (OPV) devices, the development of n-type porphyrin-based electron acceptors has been challenging. In this work, we developed a high-performance porphyrin-based electron acceptor for OPVs by substitution of four naphthalene diimide (NDI) units at the perimeter of a Zn-porphyrin (PZn) core using ethyne linkage. Effective π-conjugation between four NDI wings and the PZn core significantly broadened Q-band absorption to the near infrared region, thereby achieving the narrow band gap of 1.33 eV. Employing a windmill-structured tetra-NDI substituted PZn-based acceptor ( PZn-TNDI) and mid-band gap polymer donor (PTB7-Th), the bulk heterojunction OPV devices achieved a power conversion efficiency (PCE) of 8.15% with an energy loss of 0.61 eV. The PCE of our PZn-TNDI-based device was the highest among the reported OPVs using porphyrin-based acceptors. Notably, the amorphous characteristic of PZn-TNDI enabled optimization of the device performance without using any additive, which should make industrial fabrication simpler and cheaper.

Development of n-Type Porphyrin Acceptors for Panchromatic Light-Harvesting Fullerene-Free Organic Solar Cells.

The development of n-type porphyrin acceptors is challenging in organic solar cells. In this work, we synthesized a novel n-type porphyrin acceptor, PZn-TNI, via the introduction of the electron withdrawing naphthalene imide (NI) moiety at the meso position of zinc porphyrin (PZn). PZn-TNI has excellent thermal stability and unique bimodal absorption with a strong Soret band (300-600 nm) and weak Q-band (600-800 nm). The weak long-wavelength absorption of PZn-TNI was completely covered by combining the low bandgap polymer donor, PTB7-Th, which realized the well-balanced panchromatic photon-to-current conversion in the range of 300-800 nm. Notably, the one-step reaction of the NI moiety from a commercially available source leads to the cheap and simple n-type porphyrin synthesis. The substitution of four NIs in PZn ring induced sufficient n-type characteristics with proper HOMO and LUMO energy levels for efficient charge transport with PTB7-Th. Fullerene-free organic solar cells based-on PTB7-Th:PZn-TNI were investigated and showed a promising PCE of 5.07% without any additive treatment. To the best of our knowledge, this is the highest PCE in the porphyrin-based acceptors without utilization of the perylene diimide accepting unit.

Visible-Light-Responsive High-Detectivity Organic Photodetectors with a 1 µm Thick Active Layer.

Organic photodetectors (OPDs) are attracting attention for use in flexible and portable electronic applications such as image sensors, remote sensing, optical communications, and medical sensors because of their strong photon responsivity in thin films over a broad range of wavelengths. In particular, the efficient photon-to-current conversion of OPDs under visible light allows their use in indirect X-ray detectors using scintillators to convert X-rays to visible light. The polymer poly(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2- b:4,5- b']dithiophene- co-5-(2-hexyldecyl)-1,3-bis(6-octylthieno[3,2- b]thiophen-2-yl)-4 H-thieno[3,4- c]pyrrole-4,6(5 H)-dione) (PBDTT-8ttTPD) shows strong absorption bands in the region of 500-650 nm, as well as high hole mobility, which provides excellent photoresponsivity and photon-to-current conversion efficiency. A p-n junction photodetector was fabricated by blending PBDTT-8ttTPD and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) and varying the thickness of the active layer (260-1100 nm). The PBDTT-8ttTPD:PC71BM-based OPDs show promising photodetecting properties having a low dark current of 3.72 × 10-9 A cm-2 and high responsivity of 0.39 A W-1 because of the well-controlled morphology, high molar absorption coefficient, and excellent carrier mobility of the PBDTT-8ttTPD:PC71BM layer. Consequently, the specific detectivity of the PBDTT-8ttTPD-based OPD devices was 1.13 × 1013 Jones at -2 V on irradiation with a light-emitting diode (530 nm wavelength) with a power density of 55.6 µW cm-2.

Performance Improvement in Low-Temperature-Processed Perovskite Solar Cells by Molecular Engineering of Porphyrin-Based Hole Transport Materials.

Porphyrin derivatives have recently emerged as hole transport layers (HTLs) because of their electron-rich characteristics. Although several successes with porphyrin-based HTLs have been recently reported, achieving excellent solar cell performance, the chances to improve this further by molecular engineering are still open. In this work, Zn porphyrin (PZn)-based HTLs were developed by conjugating fluorinated triphenylamine (FTPA) wings at the perimeter of the PZn core for low-temperature perovskite solar cells (L-PSCs). The fluorinated PZn-HTLs (PZn-2FTPA and PZn-3FTPA) exhibited superior HTL properties compared to the nonfluorinated one (PZn-TPA). Moreover, their deeper highest occupied molecular orbital energy levels were beneficial for boosting open-circuit voltages, and their enhanced face-on stacking improved the hole transport properties. The L-PSC using PZn-2FTPA achieved the highest performance of 18.85%. Thus far, this result is one of the highest reported power conversion efficiencies among the PSCs using porphyrin-based HTLs.

Interfacial Modifier Having Julolidine for the Cathode Buffer Layer in PTB-7:PC70BM Based Inverted Organic Photovoltaic Cells.

The julolidine based interfacial modifier (IM-J) for cathode buffer layer following the "donor-acceptor" design concept with julolidine substituent as an electron donating moiety was incoporated to improve the surface properties of ZnO. Simple treatment of metal oxide type cathode buffer materials with organic interfacial modifier induces the enhanced photovoltaic performance and could effectively overcome several interfacial problems in inverted organic photovoltaic cells (I-OPVs). We studied on the coverage of IM-J on ZnO surface with variation of solution concentrations to reduce charge recombination and macroscopic phase separation. At the optimum condition, ZnO/IM-J (0.05 w/v%), IM-J significantly decreased the surface tension (46.1 mN/m) and improved surface morphology (RMS roughness: 0.61 nm). As a result, compared to the unmodified ZnO based device, the ZnO/IM-J based I-OPVs showed significantly improved power conversion efficiency (PCE) from 7.41 to 8.07% due to the increased photocurrent density (Jsc) and fill factor (FF). It is concluded that IM-J is one of the promising candidates for controlling electronic property of ZnO buffer layer in inverted organic photovoltaic cells. Also, our interfacial modified system can be utilized in other optoelectronic devices.

4-Diphenylaminocarbazole: Switching Substituent Position for Voltage Reduction and Efficiency Enhancement of OLEDs.

Simple but exceptionally efficient 4-diphenylaminocarbazole host material, 4-DPACz, is presented and compared with its positional isomer, 1-DPACz. The shift of diphenylamino substituent from the 1-position to 4-position of carbazole resulted in an increase in the HOMO energy level as well as an increase in triplet energy level. Having a high triplet energy level (2.76 eV) and well-matched HOMO energy level (-5.61 eV), 4-DPACz showed reduced driving voltage and higher efficiencies for solution-processed green PhOLEDs compated to PVK as well as 1-DPACz. Maximum luminous, power, and external quantum efficiencies reaching to 47.9 cd A-1, 25.2 lm W-1, and 14.3%, respectively, were achieved with a device configuration of [ITO/PEDOT:PSS/4-DPACz:Ir(mppy)3/TPBi/CsF/Al]. Additional enhancement of efficiencies of 4-DPACz was verified when incorporating another dopant, Ir(Si-bppy)2(acac), resulting in 59.1 cd A-1, 29.5 lm W-1, and 15.8%. Furthermore, reduced efficiency roll-off was clearly observed for 4-DPACz compared with PVK. Such improved device characteristics of 4-DPACz were attributed to its high hole mobility and charge balance inside the emitting layer therof. The excellent results using such a simple-structured 4-DPACz could promote various applications of this 4-DPACz unit as a building block structure for further possible oligomeric, dendritic, and polymeric materials.

Modified SnO2 with Alkali Carbonates as Robust Electron-Transport Layers for Inverted Organic Solar Cells.

We report for the first time that alkali carbonates (Li2CO3, K2CO3, and Rb2CO3) based on a low-temperature solution process can be used as interfacial modifiers for SnO2 as robust electron-transport layers (ETL) for inverted organic solar cells (iOSCs). The room-temperature photoluminescence, the electron-only devices, and the impedance studies altogether suggested the interfacial properties of the alkali carbonates-modified SnO2 ETLs, which were much better than those based on the SnO2 only, provided efficient charge transport, and reduced the charge recombination rates for iOSCs. The iOSCs using the polymer donor poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl] and the fullerene acceptor phenyl-C70-butyric acid methyl ester as the active layer showed the average power-conversion efficiencies (PCEs) based on ten devices of 6.70, 6.85, and 7.35% with Li2CO3-, K2CO3-, and Rb2CO3-modified SnO2 as ETLs, respectively; these are more than 22, 24, and 33% higher than those based on the SnO2 only (5.49%). Moreover, these iOSC devices exhibited long-term stabilities, with over 90% PCEs remaining after the devices were stored in ambient air for 6 weeks without encapsulations. We believe that alkali carbonates-modified SnO2 approaches are an effective way to achieve stable and highly efficient iOSCs and might also be suitable for other optoelectronic devices where an ETL is needed, such as perovskite solar cells or organic light-emitting diodes.

Diphenyl-2-pyridylamine-Substituted Porphyrins as Hole-Transporting Materials for Perovskite Solar Cells.

The susceptibility of porphyrin derivatives to light-harvesting and charge-transport operations have enabled these materials to be employed in solar cell applications. The potential of porphyrin derivatives as hole-transporting materials (HTMs) for perovskite solar cells (PSCs) has recently been demonstrated, but knowledge of the relationships between the porphyrin structure and device performance remains insufficient. In this work, a series of novel zinc porphyrin (PZn) derivatives has been developed and employed as HTMs for low-temperature processed PSCs. Key to the design strategy is the incorporation of an electron-deficient pyridine moiety to down-shift the HOMO levels of porphyrin HTMs. The porphyrin HTMs incorporating diphenyl-2-pyridylamine (DPPA) have HOMO levels that are in good agreement with the perovskite active layers, thus facilitating hole transfers from the perovskite to the HTMs. The DPPA-containing zinc porphyrin-based PSCs gave the best performance, with efficiency levels comparable to those of PSCs using spiro-OMeTAD, a current state-of-the-art HTM. In particular, PZn-DPPA-based PSCs show superior air stability, in both doped and undoped forms, to spiro-OMeTAD based devices.

Mortality and cancer after 12 versus 30 months dual antiplatelet therapy. The Korean Outcomes Registry Evaluating Antithrombotics (KOREA).

The optimal duration and cancer risks of antiplatelet therapy following percutaneous coronary intervention (PCI) are unclear. We compared cancer and all-cause mortality after dual antiplatelet therapy (DAPT) for the combination of clopidogrel and aspirin (ASA) versus ASA alone over 18 months follow-up in event-free patients at 12 months DAPT from the Health Insurance Review and Assessment (HIRA) dataset via the Korean Outcomes Registry Evaluating Antithrombotics (KOREA). We selected PCI patients who were event free for 12 months and maintained a consistent antiplatelet regimen for 18 more months. The primary endpoints were any cancer and all-cause mortality at 30 months follow-up after PCI. From 320,351 screened post-PCI patient HIRA records, we excluded 294,413 and qualified 25,938, constituting DAPT (n=10,992) and ASA (n=14,946) groups. The Propensity Score Matching (PSM), and Inverse Probability of Treatment Weighting (IPTW) revealed no significant differences in background demographics and clinical characteristics for DAPT versus ASA patients. At 30-months post-PCI, after massive (>91 %) exclusions, cancer risk was higher for continuous DAPT [455 (4.15 %) vs 606 (4.04 %); HR=1.221; 95 %CI: 1.061-1.405; p=0.005], which remained significant by PSM (p=0.006) or IPTW (p=0.007), while all-cause mortality was similar [136 (1.24 %) vs 192 (1.28 %) HR=0.999; 95 %CI: 0.736-1.135; p=0.993]. This analysis suggests a potential mild excess cancer risk, but no mortality benefit in Korean post-PCI patients treated with DAPT for an additional 18 months beyond conventional 12 months DAPT. These data are not supporting continuing DAPT for more than one year in East Asians. Analysing cancer types and assessing potential cancer association with bleeding are warranted.

Solution Processed Organic Photovoltaic Cells Using D-A-D-A-D Type Small Molecular Donor Materials with Benzodithiophene and Diketopyrrolopyrrole Units.

Organic photovoltaic Cells (OPVs) have been considered to be a next-generation energy source to overcome exhaustion of resources. Currently, OPVs are developed based on two types of donor material with polymer and small molecule. Polymeric donor materials have shown better power conversion efficiency (PCE) than small molecular donor materials, since it's easy to control the morphology of photoactive film. However, the difficulty in synthetic reproducibility and purification of polymeric donor were main drawback to overcome. And then, recently small molecule donor materials have been overcome bad morphology of OPVs film by using appropriate alkyl substituents and relatively long conjugation system. In this study, we designed and synthesized D-A-D-A-D type small molecular donor materials containing alternatively linked benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) units. Also, we studied on the effect of photovoltaic performance of prepared small molecular D-A-D-A-D type donor with variation of thiophene links and with/without hexyl substituent. Our small molecular donors showed HOMO energy levels from -5.26 to -5.34 eV and optical bandgaps from 1.70 to 1.87 eV by CV (cyclic voltammetry) and UV/Vis spectroscopy, respectively. Finally, 3.4% of PCE can be obtained using a mixture of BDT(DPP)2-T2 and PCBM as an active layer with a Voc of 0.78 V, a Jsc of 9.72 mA/cm2, and a fill factor of 0.44 under 100 mW/cm2 AM 1.5G simulated light. We will discuss the performance of D-A-D-A-D type small molecular donor based OPVs with variation of both terminal substituents.

Syntheses of D-A-A Type Small Molecular Donor Materials Having Various Electron Accepting Moiety for Organic Photovoltaic Application.

Small molecular donor, DTDCTB achieved a high power conversion efficiency (PCE) value of 6.6 ± 0.2% in vacuum-deposited planar mixed heterojunction (PMHJ) structure. However, the same material just recorded PCE of 0.34% in solution processed small molecule based bulk heterjunction (BHJ) organic photovoltaic cells. For the improvement of organic photovoltaic cells (OPVs), In this study, we designed and synthesized several D-A-A (donor-acceptor-acceptor) type molecular electron donating materials. Ditolylaminothienyl moiety as an electron donating group connected to 1,2,5-benzothiadiazole as a conjugated electron accepting unit, simultaneously with an electron accepting terminal group such as cyano alkyl acetate and N-alkyl rhodanine. The thermal, photophysical, and electrochemical properties of prepared small molecules were investigated by DSC, UV/Vis spectroscopy and Cyclic Voltametry, respectively. As a result, 0.89% of PCE can be obtained from OPV using a mixture of DTATBTER and PCBM as an active layer with a Voc of 0.87 V, a Jsc of 3.20 mA/cm2, and a fill factor of 31.9%.

A new prognostic model for chemotherapy-induced febrile neutropenia.

BACKGROUND: The objective of this study was to develop and validate a new prognostic model for febrile neutropenia (FN). METHODS: This study comprised 1001 episodes of FN: 718 for the derivation set and 283 for the validation set. Multivariate logistic regression analysis was performed with unfavorable outcome as the primary endpoint and bacteremia as the secondary endpoint. RESULTS: In the derivation set, risk factors for adverse outcomes comprised age ≥ 60 years (2 points), procalcitonin ≥ 0.5 ng/mL (5 points), ECOG performance score ≥ 2 (2 points), oral mucositis grade ≥ 3 (3 points), systolic blood pressure <90 mmHg (3 points), and respiratory rate ≥ 24 breaths/min (3 points). The model stratified patients into three severity classes, with adverse event rates of 6.0 % in class I (score ≤ 2), 27.3 % in class II (score 3-8), and 67.9 % in class III (score ≥ 9). Bacteremia was present in 1.1, 11.5, and 29.8 % of patients in class I, II, and III, respectively. The outcomes of the validation set were similar in each risk class. When the derivation and validation sets were integrated, unfavorable outcomes occurred in 5.9 % of the low-risk group classified by the new prognostic model and in 12.2 % classified by the Multinational Association for Supportive Care in Cancer (MASCC) risk index. CONCLUSIONS: With the new prognostic model, we can classify patients with FN into three classes of increasing adverse outcomes and bacteremia. Early discharge would be possible for class I patients, short-term observation could safely manage class II patients, and inpatient admission is warranted for class III patients.

Controlling the Morphology of BDTT-DPP-Based Small Molecules via End-Group Functionalization for Highly Efficient Single and Tandem Organic Photovoltaic Cells.

A series of narrow-band gap, π-conjugated small molecules based on diketopyrrolopyrrole (DPP) electron acceptor units coupled with alkylthienyl-substituted-benzodithiophene (BDTT) electron donors were designed and synthesized for use as donor materials in solution-processed organic photovoltaic cells. In particular, by end-group functionalization of the small molecules with fluorine derivatives, the nanoscale morphologies of the photoactive layers of the photovoltaic cells were successfully controlled. The influences of different fluorine-based end-groups on the optoelectronic and morphological properties, carrier mobilities, and the photovoltaic performances of these materials were investigated. A high power conversion efficiency (PCE) of 6.00% under simulated solar light (AM 1.5G) illumination has been achieved for organic photovoltaic cells based on a small-molecule bulk heterojunction system consisting of a trifluoromethylbenzene (CF3) end-group-containing oligomer (BDTT-(DPP)2-CF3) as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor. As a result, the introduction of CF3 end-groups has been found to enhance both the short circuit current density (JSC) and fill factor (FF). A tandem photovoltaic device comprising an inverted BDTT-(DPP)2-CF3:PC71BM cell and a poly(3-hexylthiophene) (P3HT):indene-C60-bisadduct (IC60BA)-based cell as the top and bottom cell components, respectively, showed a maximum PCE of 8.30%. These results provide valuable guidelines for the rational design of conjugated small molecules for applications in high-performance organic photovoltaic cells. Furthermore, to the best of our knowledge, this is the first report on the design of fluorine-functionalized BDTT-DPP-based small molecules, which have been shown to be a viable candidate for use in inverted tandem cells.