Herein, we clearly demonstrate that the inclusion of the organic solid additive (2,3-dihydroxypyridine, DOH) into the poly(diketopyrrolopyrrole-terthiophene) (PDPP3T) and phenyl-C61-butyric acid ...methyl ester (PCBM) (PDPP3T:PCBM) photoactive blend system alters the nanoscale morphology and enhances the photovoltaic (PV) performance of the inverted bulk heterojunction (BHJ) based polymer solar cells (PSCs). The influence of DOH additive casted PDPP3T: PCBM thin films on the optical, morphology and structural features is evaluated and correlated with PV characteristics. Topography images through atomic force microscopy reveal that the incorporation of DOH into PDPP3T: PCBM induces a finer nanoscale phase segregation between polymer and fullerene domains with fibrillar morphology. The PV performance of the DOH processed PDPP3T: PCBM devices is evaluated by current-voltage (J-V) characteristics and compared with pristine and 1, 8-diiodooctane (DIO) modified PDPP3T: PCBM devices. Interestingly, the incorporation of DOH (0.5 wt%) into PDPP3T: PCBM device witnessed the best PCE of 6.36%, which is significantly higher (69.1%) than that of the reference (3.76%). This significant enhancement in the performance of the device is mainly attributed to a dramatic increase in the short-circuit current density and fill-factor due to the improved bicontinuous interpenetrated phase separation and balanced charge transport. In addition, the measurements on photo-induced charge carrier extraction by linearly increasing voltage reveal that DOH incorporated devices exhibit higher mobility and charge carrier density as compared to those of pristine modified BHJ PSCs. The presence of vicinal functional groups in DOH contributes to the possible molecular level interactions with the blend components and accounts for the morphology and device performance enhancements.
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•The inclusion of the functional solid additive, 2,3-dihydroxypyridine (DOH) significantly (69.1%) enhanced the efficiency.•DOH has two vicinal hydroxyl groups for augmenting the molecular level interactions with photoactive blend components.•Systematically evaluated the influence of DOH through morphology, optoelectronic and film/device characterizations.•The nanomorphology modifications by DOH contribute as the major factor for the enhancement of photovoltaic performance.•The molecular structures of the DOH and components play pivotal role on the morphology and device performance enhancements.
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is most commonly used as an anode buffer layer in bulk-heterojunction (BHJ) polymer solar cells (PSCs). However, its hygroscopic ...and acidic nature contributes to the insufficient electrical conductivity, air stability and restricted photovoltaic (PV) performance for the fabricated PSCs. In this study, a new multifunctional additive, 2,3-dihydroxypyridine (DOH), has been used in the PEDOT: PSS buffer layer to obtain modified properties for PEDOT: PSS@DOH and achieve high PV performances. The electrical conductivity of PEDOT:PSS@DOH films was markedly improved compared with that of PEDOT:PSS. The PEDOT:PSS@DOH film exhibited excellent optical characteristics, appropriate work function alignment, and good surface properties in BHJ-PSCs. When a poly(3-hexylthiohpene):6,6-phenyl C
-butyric acid methyl ester blend system was applied as the photoactive layer, the power conversion efficiency of the resulting PSCs with PEDOT:PSS@DOH(1.0%) reached 3.49%, outperforming pristine PEDOT:PSS, exhibiting a power conversion enhancement of 20%. The device fabricated using PEDOT:PSS@DOH (1.0 wt%) also exhibited improved thermal and air stability. Our results also confirm that DOH, a basic pyridine derivative, facilitates adequate hydrogen bonding interactions with the sulfonic acid groups of PSS, induces the conformational transformation of PEDOT chains and contributes to the phase separation between PEDOT and PSS chains.
The particle size and trap energy level of ZnO were adjusted by varying the concentration of precursors using a sol–gel process, and the energy transport properties of the electron transport layer in ...quantum dot light-emitting diodes (QD-LEDs) were analyzed. Thus far, no study has considered the efficient electron transport properties of quantum dot light-emitting devices with respect to trap energy levels owing to the oxygen vacancies of ZnO. The particle size and trap energy levels of ZnO were analyzed based on optical properties such as photoluminescence and absorbance. The optimized device showed excellent performance, with a maximum luminance of 50,120 cd/m2, a high efficiency of 5.85 cd/A, and a threshold voltage of 2.5 V. The Y-ZnO (yellow photoluminescence ZnO)-based QD-LEDs not only enhanced the injection efficiency of electrons into the emitting layer but also confined the holes in the emitting layer due to the shallow trap level of Y-ZnO, in contrast to the deep trap levels of G-ZnO (green photoluminescence ZnO) and B-ZnO (blue photoluminescence ZnO). Here, we present the first attempt to analyze the electron transport behavior of the electron transport layer of the resulting device.
We attempted surface modification in ZnO nanoparticles (NPs) synthesized by the sol-gel process with polyvinyl pyrrolidone (PVP) applied to bulk-heterojunction polymer solar cells (PSCs) as an ...electron transport layer (ETL). In general, ZnO NPs have trap sites due to oxygen vacancies which capture electrons and degrade the performance of the PSCs. Devices with six different PVP:Zn ratios (0.615 g, 1.230 g, 1.846 g, 2.460 g, 3.075 g, and 3.690 g) were fabricated for surface modification, and the optimized PVP:Zn ratio (2.460 g) was found for PSCs based on P3HT/PCBM. The power conversion efficiency (PCE) of the fabricated PSCs with PVP-capped ZnO exhibited a significant increase of approximately 21% in PCE and excellent air-stability as compared with the uncapped ZnO-based PSCs.
Porcine reproductive and respiratory syndrome virus (PRRSV) is an epidemic etiology in pigs of all ages causing reproductive failure and respiratory manifestation. PRRSV has been circulating in ...Chinese pig farms for almost 20 years. The aim of the present study was to fully understand the extent of the genetic diversity and molecular characteristics of PRRSVs in Central China. A strain of PRRSV isolated from a recent outbreak farm in Hunan province in Central China, designated HUN-2014, was sequenced and analyzed with 39 other PRRSVs from 1998 to 2014 in Central China. Comparative results of genomic sequences revealed that all 40 PRRSVs belonged to the North American genotype (NA genotype) and shared 88.8–99.0% homology. Phylogenetic analysis showed three subgenotypes, namely conventional PRRSV (C-PRRSV), specially mutant PRRSV (S-PRRSV) and highly pathogenic PRRSV (HP-PRRSV), in all 40 PRRSVs. Moreover, comparative analysis of amino acid (AA) sequences of NSP2, GP3, GP5 and ORF5a revealed the main evolution trend of PRRSVs in Central China from 1998 to 2014, which was from C-PRRSV to HP-PRRSV, accompanied by different evolving directions to S-PRRSV. In conclusion, both the major evolutionary trend and special features of genetic variation should be emphasized as theoretical basis for development of new vaccines and control strategies for PRRS.
We investigated the role of a functional solid additive, 2,3-dihydroxypyridine (DHP), in influencing the optoelectronic, morphological, structural and photovoltaic properties of ...bulk-heterojunction-based polymer solar cells (BHJ PSCs) fabricated using poly(3-hexylthiophene): indene-C60 bisadduct (P3HT:IC60BA) photoactive medium. A dramatic increase in the power conversion efficiency (~20%) was witnessed for the BHJ PSCs treated with DHP compared to the pristine devices. A plausible explanation describing the alignment of pyridine moieties of DHP with the indene side groups of IC60BA is presented with a view to improving the performance of the BHJ PSCs via improved crystalline order and hydrophobicity changes.
In bulk heterojunction polymer solar cells (BHJ-PSCs), poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) is the most commonly used hole selective interlayer (HSIL). ...However, its acidity, hygroscopic nature, and the use of indium tin oxide (ITO) etching can degrade the overall photovoltaic performance and the air-stability of BHJ-PSCs. Solvent engineering is considered as a facile approach to overcome these issues. In this work, we engineered the HSIL using ethanol (ET) treated PEDOT:PSS to simultaneously enhance the photovoltaic performance properties and air-stability of the fabricated devices. We systematically investigated the influence of ET on the microstructural, morphological, interfacial characteristics of modified HSIL and photovoltaic characteristics of BHJ-PSCs. Compared with the BHJ-PSC with pristine PEDOT:PSS, a significant enhancement of power conversion efficiency (~17%) was witnessed for the BHJ-PSC with PEDOT:PSS-ET (
/
, 1:0.5). Consequently, the BHJ-PSC with PEDOT:PSS-ET (
/
, 1:0.5) as HSIL exhibited remarkably improved air-stability.
A compatible low-bandgap donor polymer (polyN-90-heptadecanyl-2,7carbazole-alt-3,6-bis(thiophen-5-yl)-2,5-dioctyl-2,5-dihydropyrrolo 3,4 pyrrole-1,4-dione, PCBTDPP) was judicially introduced into the ...archetypal poly(3-hexylthiophene):6,6-phenyl-C
-butyric acid methyl ester (P3HT:PC
BM) photoactive system to fabricate highly efficient ternary based bulk heterojunction polymer solar cells (PSCs). The PCBTDPP ternary-based PSC with optimal loading (0.2 wt.%) displayed outstanding performance with a champion power conversion efficiency (PCE) of 5.28% as compared to the PCE (4.67%) for P3HT:PC
BM-based PSC (reference). The improved PCE for PCBTDPP ternary-based PSC can be mainly attributed to the incorporation of PCBTDPP into P3HT:PC
BM that beneficially improved the optical, morphological, electronic, and photovoltaic (PV) performance. This work instills a rational strategy for identifying components (donor/acceptor (D/A) molecules) with complementary beneficial properties toward fabricating efficient ternary PSCs.
Currently, many researchers are focused on promising new energy technologies such as Cu2ZnSnS4-based solar cells to replace fossil fuel sources. Investigations into a variety of methods have been ...done to analyze the interfacial problems and improve the cell interfacial properties via a variety of methods. In particular, In order to improve the electrical performance of Cu2ZnSnSe4 (CZTSe) based solar cells, the Cd partial electrolyte (Cd PE) treatment that is an effective method in CIGS solar cells prior to applying their CdS buffer layer to their absorber layer has been studied. In our study, we investigated the Cd PE treatment time, the Cd PE bath temperature, and the correlation between Cd PE treatment and CdS thickness. The optimum Cd PE absorber treatment was 7min at 70°C, with a CdS layer of 35nm thick deposited cells. This combination increased photo-carrier collection in the short wavelength range and reduced absorber-buffer interface recombination. The efficiency of a 35nm buffer layer sample without PE treatment was 8.90%. The efficiency of another 35nm buffer layer sample was 10.38% (Voc: 441mV, Jsc: 38.15mA/cm2, and FF: 61.58%) after Cd PE treatment due to the increase of Jsc, FF and Rs despite the deficit of Voc.
Shortwave infrared (SWIR) sensors have attracted interest due to their usefulness in applications like military and medical equipment. SWIR sensors based on various materials are currently being ...studied. However, most SWIR detectors need additional optical filters and cooling systems to detect specific wavelengths. In order to overcome these limitations, we proposed a solution processed SWIR sensor that can operate at room temperature using lead chloride (PbS) QDs as a photoactive layer. Additionally, we adapted zinc oxide (ZnO) nanoparticles (NPs) as an electron transport layer (ETL) to improve the sensitivity of a PbS SWIR sensor. In this study, PbS SWIR sensors with and without a ZnO NPs layer were fabricated and their current-voltage (I-V) characteristics were measured. The on/off ratio of the PbS SWIR sensor with ZnO NPs was 2.87 times higher than that of the PbS SWIR sensor without ZnO NPs at the maximum current difference. The PbS SWIR sensor with ZnO NPs showed more stable current characteristics than that without ZnO NPs because of the ZnO NPs' high electron mobility and proper lowest unoccupied molecular orbital (LUMO) level.
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