Synthesis and characterization of novel organic semiconducting materials for organic field effect transistors (OFETs) and photovoltaics (OPVs)

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Herbal plants for children diseases’ cure in Perambalur, Tamil Nadu, India

The present study aims at identification and documentation of the medicinal plants which are traditionally used to manage children diseases in Perambalur district of Tamil Nadu, India. Semi-structured interviews were used to collect ethnomedicinal plants during the month of December 2017 and January 2018. Data was statistically analysed using Use value (UV), relative frequency of citations (RFC), utility ratio (UR), relative information (RI) and informant agreement ratio (IAR). Forty three medicinal plants which were identified and documented belong to 30 families. Most of the species belong to Solanaceae and Leguminosae families. Most frequently used plant part and life form are leaves and herbs. Decoction method was used for delivering the oral dose and oral intake was the major route used for administration. Ocimum basilicum had highest UV, RFC, UR, RI and IAR. Maximum plant species were able to cure gastrointestinal diseases followed by fever, liver disorders, respiratory disorders, dermatological problem, ENT problems, etc. The results of this study revealed that Perambalur district has rich plant diversity and people have broad indigenous knowledge of role in curing children diseases. Hence, further phytochemical, pharmacological and toxicological investigation on floras that scored highest RFC and UV values is necessary for discovering new drugs

Fused H-shaped tetrathiafulvalene-oligothiophenes as charge transport materials for OFETs and OPVs

A series of hybrid tetrathiafulvalene-oligothiophene compounds has been synthesised, where the tetrathiafulvalene unit is fused at each side to an end-capped oligothiophene chain of varying length (terthiophene, quinquithiophene and septithiophene). Each hybrid structure (1-3) has been studied by cyclic voltammetry and triple EPR-UV-Vis-NIR spectroelectrochemistry in the case of the quinquithiophene compound (2). Comparison is made with the corresponding half-units, which lack the fulvalene core and contain just one oligothiophene chain. The highest hole mobility of quinquithiophene-TTF 2 was obtained from field effect transistors (8.61 × 10-3 cm 2 V-1 s-1); its surface morphology was characterised by tapping mode atomic force microscopy and a power conversion of 2.5% was achieved from a bulk heterojunction organic solar cell device using PC71BM as the acceptor. This journal is © the Partner Organisations 2014

An air-stable DPP-thieno-TTF copolymer for single-material solar cell devices and field effect transistors

Following an approach developed in our group to incorporate tetrathiafulvalene (TTF) units into conjugated polymeric systems, we have studied a low band gap polymer incorporating TTF as a donor component. This polymer is based on a fused thieno-TTF unit that enables the direct incorporation of the TTF unit into the polymer, and a second comonomer based on the diketopyrrolopyrrole (DPP) molecule. These units represent a donor–acceptor copolymer system, p(DPP-TTF), showing strong absorption in the UV–visible region of the spectrum. An optimized p(DPP-TTF) polymer organic field effect transistor and a single material organic solar cell device showed excellent performance with a hole mobility of up to 5.3 × 10–2 cm2/(V s) and a power conversion efficiency (PCE) of 0.3%, respectively. Bulk heterojunction organic photovoltaic devices of p(DPP-TTF) blended with phenyl-C71-butyric acid methyl ester (PC71BM) exhibited a PCE of 1.8%

E-textile technology review - from materials to application

Wearable devices are ideal for personalized electronic applications in several domains such as healthcare, entertainment, sports and military. Although wearable technology is a growing market, current wearable devices are predominantly battery powered accessory devices, whose form factors also preclude them from utilizing the large area of the human body for spatiotemporal sensing or energy harvesting from body movements. E-textiles provide an opportunity to expand on current wearables to enable such applications via the larger surface area offered by garments, but consumer devices have been few and far between because of the inherent challenges in replicating traditional manufacturing technologies (that have enabled these wearable accessories) on textiles. Also, the powering of e-textile devices with battery energy like in wearable accessories, has proven incompatible with textile requirements for flexibility and washing. Although current e-textile research has shown advances in materials, new processing techniques, and one-off e-textile prototype devices, the pathway to industry scale commercialization is still uncertain. This paper reports the progress on the current technologies enabling the fabrication of e-textile devices and their power supplies including textile-based energy harvesters, energy storage mechanisms, and wireless power transfer solutions. It identifies factors that limit the adoption of current reported fabrication processes and devices in the industry for mass-market commercialization

Spray coated textile solar cells

E-textiles are a promising platform for wearable technologies, but these face the ubiquitous challenge of supplying power. One approach is to harvest ambient solar energy. Here we present a novel fully solution processed fabrication method and achieved on both organic solar cells (OSCs) and solid state dye sensitised solar cells (ssDSSCs), which were deposited directly on the surface of a standard woven textiles. A polyester cotton textile was used for the OSCs and a glass fibre textile substrate was used for the ssDSSCs that contain multiple layers of electrodes and active materials. All PV textile devices were characterized under simulated AM 1.5 conditions and a peak efficiency of 1.23% for OSCs and 0.4% for DSSCs was achieved. The fabrication approach demonstrates the feasibility of fabricating OSCs on any standard textile and ssDSSCs onto glass fibre textiles.</p