Azzuliani Supangat

Improvement in the photovoltaic properties of hybrid solar cells by incorporating a QD-composite in the hole transport layer

A hybrid solar cell (HSC) based on a ZnSe and CdSe QDs-composite with improved conversion efficiency has been demonstrated. A novel approach of incorporating a QDs-composite (CdSe and ZnSe QDs simultaneously), in the poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonate) (PEDOT : PSS) matrix by a simple cost effective solution processing technique, has been adopted. The combination of the QDs produced a 33% increase in the photo-conversion efficiency with a corresponding 67% enhancement in the fill factor (FF) when compared with the reference device. The micro-Raman analysis revealed effective strong coupling between both ZnSe and CdSe QDs, which promotes smooth charge transfer. This improved efficiency due to enhanced FF was achieved through interfacial engineering of the solution-processed hole transport layer, leading to facilitated charge transport and restrained bimolecular recombination. The present approach, outdoing the need of a cascaded layered structure, is compatible with the state-of-the-art hybrid solar cells, thus offering better throughput and a low cost manufacturing process for an improved-performance device.

Surface plasmon resonance and photoluminescence studies of Au and Ag micro-flowers

The surface plasmon resonance (SPR) and photoluminescence characteristics of gold and silver micro-flowers were compared to those of gold and silver nanoparticles. The micro-flower structures were grown under electron beam deposition using an alumina template. Both types of metallic micro-flowers showed systematic arrangements; they formed islands of flowers about 20 µm across, each one comprised of spikes ranging from 1 to 5 µm in length. A red shift in the SPR and enhancement intensity was observed for both micro-flowers and nanoparticles; the incremental increase was more than 50%. These results, which showed that gold and silver micro-flowers agglomerate at a micron size scale, are useful for the design of easier and more cost effective methods for large area fabrication, especially for particular plasmonic applications.

Controlling the morphological, structural, and optical properties of one-dimensional PCDTBT nanotubes by template wetting

In this study, the synthesis of poly [N-9′-heptadecanyl-2, 7-carbazole-alt-5, 5-(4′, 7′-di-2-thienyl-2′, 1′, 3′-benzothiadiazole)] (PCDTBT) nanotubes via a templating method is reported. PCDTBT nanotubes were successfully grown by immersing the porous alumina template into 15 mg/ml of solution concentration for 2- and 24-h periods and annealed at 50°C. Changes in morphological and optical properties between nanotubes of different infiltration times (2 and 24 h) as well as its thin films are observed. The longer infiltration time of 24 h produced nanotubes with enhanced morphological, structural, and optical properties. Nanotubes that are formed between 2 and 24 h of infiltration show enhancement in absorption, photoluminescence, and shift in Raman peak if compared to their thin films.

Formation of PCDTBT:PC71BM p–n junction composite nanotubes via a templating method

The use of a templating method to synthesize a p–n junction composite of poly[N-90-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thie-nyl 20,10,30 benzothiadiazole)] (PCDTBT):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) is reported in this study. These materials have been studied due to their potential applications in organic electronic-based devices. Intimate contact between these materials can be realised via a facile fabrication using the template-assisted method. The formation of a p–n junction composite was elaborated in which its properties were compared to its bulk heterojunction counterpart. PCDTBT nanorods, nanotubes and nanoflowers were first produced followed by infiltration of PC71BM. A remarkable pattern at the first peak (carbazole) could be seen from the UV-vis spectra of the PCDTBT:PC71BM p–n junction composite nanotubes at a higher concentration of 15 mg ml−1. However, the reverse condition was seen for its lower concentration of 5 mg ml−1, which showed improvement in the second peak (DTBT) in the UV-vis spectra. The first peak of the 10 mg ml−1 solution concentration shows a wider peak compared to the 5 and 15 mg ml−1 concentrations with its second peak having fallen between these two concentrations. Unlike the PCDTBT:PC71BM bulk-heterojunction, which showed better quenching, PCDTBT:PC71BM composite nanotubes have shown a significant red-shift in their photoluminescence (PL) spectra. Despite having a significant red-shift, the PCDTBT:PC71BM junction composites displayed poor quenching properties.

Synthesis of indium oxide nanowires encapsulated in amorphous carbon nanostructures on indium tin oxide substrate

Abstract Indium oxide nanowires encapsulated in amorphous carbon nanostructures have been synthesised on iron coated indium tin oxide substrate via the chemical vapour deposition of acetylene (C2H2). The growth of indium oxide nanowires encapsulated in amorphous carbon nanostructures via solid–liquid–solid mechanism was suggested. The morphology, composition and structure of indium oxide nanowires encapsulated in amorphous carbon nanostructures were characterised by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy.

Improving the properties of VTP by incorporating fullerene

In this study, fabrication of vanadyl 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis(dimethylamino)-29H,31H-phthalocyanine (VTP):[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) composite nanotubes is proven to be successful. VTP:PC71BM composite nanotubes were fabricated via a layer-by-layer method with the assistance of a templating technique. Field emission scanning electron microscopy (FESEM) images have shown successful infiltration of the VTP solution and the further replication of the template with different morphological properties. Infiltration of PC71BM and replication of VTP nanotubes have led to the improvement of morphological, optical and structural properties. Photo-absorption analysis via a UV-vis spectrometer has shown the remarkable absorption spectra of VTP nanotubes (p-type) as well as a further enhancement after the PC71BM (n-type) is introduced into the pre-synthesized nanotubes. Significant red-shifts in the Q-band and B-band region of the VTP:PC71BM composite nanotubes are observed with the incorporation of PC71BM. Morphological analysis of composite nanotubes with different behavior of infiltration has proven influential towards the optical behavior as well as their structural properties.

Determining the Effect of Centrifugal Force on the Desired Growth and Properties of PCPDTBT as p-Type Nanowires

In this study, low-bandgap polymer poly{[4,4-bis(2-ethylhexyl)-cyclopenta-(2,1-b;3,4-b′)dithiophen]-2,6-diyl-alt-(2,1,3-benzothiadiazole)−4,7-diyl} (PCPDTBT) nanostructures have been synthesized via a hard nanoporous alumina template of centrifugal process. Centrifuge has been used to infiltrate the PCPDTBT solution into the nanoporous alumina by varying the rotational speeds. The rotational speed of centrifuge is directly proportional to the infiltration force that penetrates into the nanochannels of the template. By varying the rotational speed of centrifuge, different types of PCPDTBT nanostructures are procured. Infiltration force created during the centrifugal process has been found a dominant factor in tuning the morphological, optical, and structural properties of PCPDTBT nanostructures. The field emission scanning electron microscopy (FESEM) images proved the formation of nanotubes and nanowires. The energy-dispersive X-ray spectroscope (EDX) analysis showed that the nanostructures were composed of PCPDTBT with complete dissolution of the template.

Infiltration of VOPcPhO into porous alumina template grown by in situ method

In this study, the fabrication of in situ anodic alumina template (AAO) directly onto glass substrate is realized by varying stirring speeds and molarity of phosphoric acid. Porous alumina template is used to infiltrate vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO) prior to formation of the alumina:VOPcPhO nanocomposite. VOPcPhO was observed to fully infiltrate the template with excess formation of the VOPcPhO layer on top of the porous template after lengthy immersion of 6 h. Uniformity and density of pore size, and available pores, can be respectively tuned by varying the stirring speeds (0–300 rpm) and the molarity of the pore widening agent (0–10% of phosphoric acid). Rounded-sphere pore shapes observed with the higher transparency template were correlated with stirring speed at 100 and 200 rpm. At these speeds, the templates pore size and pore density are highly homogeneous. Changing molarity of phosphoric acid as a pore widening agent affected pore size and density. The occurrence of merging pores was observed upon increasing agent molarity to 10%, which was unlikely at the lower molarity of 5% phosphoric acid. Optical properties of alumina:VOPcPhO nanocomposites that were identified via characterization of UV-vis, photoluminescence (PL) and Raman spectroscopies support successful infiltration of VOPcPhO. Alumina:VOPcPhO nanocomposite has the ability to absorb light at longer wavelengths and photons are emitted by the nanocomposite at respective energies.

Templated growth of poly(p-phenylenevinylene) nanostructures by chemical vapour deposition

Abstract Poly(p-phenylenevinylene) nanostructures have been successfully synthesised via chemical vapour deposition into a porous alumina template. Poly(p-phenylenevinylene) layers with different textures were created by varying the angle between the template and the precursor gas flow. These different morphologies are characterised by differences in their optical emission spectra, in which the synthesis of these nanostructures opens up perspectives for nanoelectronic devices and sensors application.

Chemical vapour deposition of poly(p-phenylenevinylene) nanofilms for use in organic photovoltaics

Abstract Poly(p-phenylenevinylene) (PPV) nanofilms have been successfully synthesised via chemical vapour deposition for use in organic photovoltaics (OPVs). A bilayer OPV structure was fabricated by incorporating a layer of PPV as an electron donor and [6,6]-phenyl-C61-butyric acid methyl ester as an electron acceptor. The photovoltaic properties of these devices are discussed.