Employing PCBTDPP as an efficient donor polymer for high performance ternary polymer solar cells

A compatible low-bandgap donor polymer (poly[N-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-C61-butyric acid methyl ester (P3HT:PC61BM) 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:PC61BM-based PSC (reference). The improved PCE for PCBTDPP ternary-based PSC can be mainly attributed to the incorporation of PCBTDPP into P3HT:PC61BM 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

Improving Air-Stability and Performance of Bulk Heterojunction Polymer Solar Cells Using Solvent Engineered Hole Selective Interlayer

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 (v/v, 1:0.5). Consequently, the BHJ-PSC with PEDOT:PSS-ET (v/v, 1:0.5) as HSIL exhibited remarkably improved air-stability

Intelligent control of biped robot with heterogeneous legs

Intelligent bionic leg (IBL) is important for above-knee amputees. Biped robot with heterogeneous legs (BRHL) including artificial leg and bionic leg is proposed as a good test-bed for IBL. Mechanism and virtual prototype of BRHL is designed and built. Model of BRHL is established. Based on the complex differential algebraic equation of bionic leg, computed torque and PD feedback control of joint angle are introduced for gait tracking. The iterative learning control is applied in conjunction with computed torque and PD control law for good tracking performance. Control simulation is done and shows intelligent control is good for BRHL. Copyright © 2005 IFAC

Improving Photovoltaic Properties of P3HT:IC60BA through the Incorporation of Small Molecules

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

Uncooled Short-Wave Infrared Sensor Based on PbS Quantum Dots Using ZnO NPs

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