3 research outputs found
Blending of n‑type Semiconducting Polymer and PC<sub>61</sub>BM for an Efficient Electron-Selective Material to Boost the Performance of the Planar Perovskite Solar Cell
The
highly efficient CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite
solar cell (PeSC) is simply achieved by employing a blended electron-transport
layer (ETL) consisting of PC<sub>61</sub>BM and PÂ(NDI2OD-T2). The
high molecular weight of PÂ(NDI2OD-T2) allows for a thinned ETL with
a uniform morphology that optimizes the PC<sub>61</sub>BM ETL more
effectively. As a result of this enhancement, the power conversion
efficiency of a PC<sub>61</sub>BM:PÂ(NDI2OD-T2)-based PeSC is 25% greater
than that of the conventional PC<sub>61</sub>BM based-PeSC; additionally,
the incorporation of PÂ(NDI2OD-T2) into PC<sub>61</sub>BM attenuates
the dependence of the PeSC on the ETL-processing conditions regarding
its performance. It is revealed that, in addition to the desirable
n-type semiconducting characteristics of PC<sub>61</sub>BM:PÂ(NDI2OD-T2)î—¸including
a higher electron-mobility and a more-effective electron selectivity
of a blended ETL for an efficient electron extractionî—¸the superior
performance of a PC<sub>61</sub>BM:PÂ(NDI2OD-T2) device is the result
of a thinned and uniformly covered ETL on the perovskite layer
Highly Efficient, Color-Reproducible Full-Color Electroluminescent Devices Based on Red/Green/Blue Quantum Dot-Mixed Multilayer
Over the past few years the performance of colloidal quantum dot-light-emitting diode (QLED) has been progressively improved. However, most of QLED work has been fulfilled in the form of monochromatic device, while full-color-enabling white QLED still remains nearly unexplored. Using red, green, and blue quantum dots (QDs), herein, we fabricate bichromatic and trichromatic QLEDs through sequential solution-processed deposition of poly(9-vinlycarbazole) (PVK) hole transport layer, two or three types of QDs-mixed multilayer, and ZnO nanoparticle electron transport layer. The relative electroluminescent (EL) spectral ratios of constituent QDs in the above multicolored devices are found to inevitably vary with applied bias, leading to the common observation of an increasing contribution of a higher-band gap QD EL over low-band gap one at a higher voltage. The white EL from a trichromatic device is resolved into its primary colors through combining with color filters, producing an exceptional color gamut of 126% relative to National Television Systems Committee (NTSC) color space that a <i>state-of-the-art</i> full-color organic LED counterpart cannot attain. Our trichromatic white QLED also displays the record-high EL performance such as the peak values of 23 352 cd/m<sup>2</sup> in luminance, 21.8 cd/A in current efficiency, and 10.9% in external quantum efficiency
Palladium-Decorated Hydrogen-Gas Sensors Using Periodically Aligned Graphene Nanoribbons
Polymer residue-free graphene nanoribbons (GNRs) of 200 nm
width at 1 μm pitch were periodically generated in an area of
1 cm<sup>2</sup> via laser interference lithography using a chromium
interlayer prior to photoresist coating. High-quality GNRs were evidenced
by atomic force microscopy, micro-Raman spectroscopy, and X-ray photoelectron
spectroscopy measurements. Palladium nanoparticles were then deposited
on the GNRs as catalysts for sensing hydrogen gases, and the GNR array
was utilized as an electrically conductive path with less electrical
noise. The palladium-decorated GNR array exhibited a rectangular sensing
curve with unprecedented rapid response and recovery properties: 90%
response within 60 s at 1000 ppm and 80% recovery within 90 s in nitrogen
ambient. In addition, reliable and repeatable sensing behaviors were
revealed when the array was exposed to various gas concentrations
even at 30 ppm