Yu-Ping Lee

A new strategy for co-assembling π-conjugated polymer/cadmium sulfide hybrids into an efficient charge-transporting nanochannel array by using an all-conjugated diblock copolymer motif

In this study, a novel organic/inorganic hybrid material containing cadmium sulfide (CdS) nanoparticles was synthesized in situ by using an all π-conjugated block copolymer as both a synergistic long-range ordered structure-directing template and an efficient exciton quencher for the nanohybrid. The conducting–conducting block copolymer of poly(2,5-dihexyloxy-para-phenylene)-b-poly(3-hexyl thiophene) (PPP-P3HT) was used as a linear nanoreactor for the quantum dot synthesis to yield nanohybrids with highly ordered donor/acceptor (D/A) nanowire morphology that exhibit enhanced optoelectronic properties. The synthesized PPP-P3HT/CdS-OH nanohybrid possessed a one-dimensional D/A coaxial nanowire structure of uniform width (∼10 nm), wherein the synthesized CdS quantum dots were embedded, resulting in a display of superior long-term stability in a solution medium. By a simple drop casting process, the hybrid materials with highly ordered organic/inorganic nanochannel arrays could also be preserved in a thin film state, as evidenced by TEM and X-ray measurements, for device applications. The PPP-P3HT block copolymer exhibited significantly better hole mobility than its P3HT homopolymer counterpart. In addition, the resulting PPP-P3HT/CdS-OH hybrid systems displayed a considerably enhanced PL quench effect and shorter exciton lifetime due to efficient charge transfer between the P3HT block and the confining CdS nanoparticles in the P3HT/CdS coaxial domain of the hybrid nanowire structure. Therefore, the PPP-P3HT/CdS-OH nanohybrids can be used as bicontinuous nanochannels for efficient charge separation and charge transport, which show potential for use in future optoelectronic applications.

One-step in situ hydrothermal fabrication of D/A poly(3-hexylthiophene)/TiO2 hybrid nanowires and its application in photovoltaic devices

In this study, we developed a novel in situ hydrothermal method to fabricate self-assembled P3HT/TiO2 hybrid nanowires, wherein a facile one-step synthetic strategy was utilized to co-organize P3HT molecules and titanium precursors into highly elongated hybrid nanowires, followed by a hydrothermal process in an autoclave to in situ transform the titanium precursors into crystalline TiO2 nanoparticles on the P3HT nanofibrils. P3HT nanofibrils were utilized as a structure-directing motif to achieve a favorable dispersion of electron acceptor (A) TiO2 nanocrystals of 10–15 nm in diameter embossed along the nanofibrils, as well as an efficient electron donor (D) for the nanohybrid. In particular, the crystallization temperature of anatase-phase TiO2 nanoparticles with high crystallinity obtained via the hydrothermal method was significantly reduced to 130 °C in an elevated pressure of ∼7 bars as compared to the conventional calcination temperature of 450 °C at ambient pressure for TiO2 nanocrystal synthesis, therefore, allowing the synergistic one-step fabrication of both highly crystalline TiO2 nanoparticles embossed on highly crystalline long-range ordered P3HT nanofibrils. As a consequence of the structural development, this P3HT/TiO2 embossed nanohybrid could afford significant improvements in its D/A interfacial contact area for effective charge separation without the need for capping ligands typically used in ex situ D/A blend systems, as well as an efficient pathway for charge transport, leading to enhanced optoelectronic properties and device performance. The highest conversion efficiency of 0.14% was presented by the P3HT/TiO2 embossed hybrid device, which was a remarkable improvement as compared to only 0.03% from an ex situ P3HT/TiO2 hybrid device. This novel in situ approach shows a feasible way to fabricate organic/inorganic nanohybrid materials of conjugated copolymers with different inorganic nanoparticles for the applications of future optoelectronic devices.

Design and Implementation of a Novel Triangular Planar Maglev System

This paper describes a novel design of a single-deck and triangular planar maglev system. The proposed design does not depend on the conventional linear slideways or high temperature superconductors (HTS), instead, the design consists of fixed solenoid electromagnets and a permanent magnet carrier stage with the magnets set up in the triangular position. The basic idea is come up with a solenoid excitation that can create a restoring force to position and the property of natural stability with the triangular shape. For verification, we build a prototype experimental system.