National Institute for Solar Energy

Delhi, India

National Institute for Solar Energy

Delhi, India

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Siva Kumar G.,Crop Protection Chemicals Division | Srinivas K.,Crop Protection Chemicals Division | Shanigaram B.,Inorganic and Physical Chemistry Division | Bharath D.,Crop Protection Chemicals Division | And 8 more authors.
RSC Advances | Year: 2014

We have designed and synthesized four new metal free D-A-π-A type dyes (9-12) with variations in their acceptor/anchor groups. The four dyes carry tert-butyl substituted triphenylamine as donor, thiadiazole as acceptor and bithiophene as π-spacer. Cyanoacetic acid, rhodanine-3-acetic acid, 2-(4-methoxyphenyl)acetic acid and 2-phenylacetic acid are used as acceptor/anchor groups, respectively in the dyes 9-12. The acceptor/anchor effect on their photophysical, electrochemical and photovoltaic properties was investigated. The dyes exhibited good power conversion efficiency ranging from 1.95-4.12%. Among the four dyes, 9 showed the best photovoltaic performance: short-circuit current density (Jsc) of 8.50 mA cm-2, open-circuit voltage (Voc) of 645 mV and fill factor (FF) of 0.75, corresponding to an overall conversion efficiency of 4.12% under standard global AM 1.5 solar light conditions. This journal is © the Partner Organisations 2014.


News Article | January 29, 2016
Site: www.treehugger.com

Over the next five years, France will install some 621 miles (1,000km) of solar roadway using Colas' Wattway solar pavement. Solar freakin' roadways! No, this is not the crowdfunded solar road project that blew up the internet a few years ago, but is a collaboration between Colas, a transport infrastructure company, and INES (France's National Institute for Solar Energy), and sanctioned by France's Agency of Environment and Energy Management, which promises to bring solar power to hundreds of miles of roads in the country over the next five years. One major difference between this solar freakin' roadway and that other solar freakin' roadway is that the new Wattway system doesn't replace the road itself or require removal of road surfaces, but instead is designed to be glued onto the top of existing pavement. The Wattway system is also built in layers of materials "that ensure resistance and tire grip," and is just 7 mm thick, which is radically different from that other design that uses thick glass panels (and which is also claimed to include LED lights and 'smart' technology, which increases the complexity and cost of the moose-friendly solar tiles). According to Colas, the material is strong enough to stand up to regular traffic, even heavy trucks, and 20 m² of Wattway panels is said to provide enough electricity to power a single average home in France, with a 1-kilometer stretch of Wattway road able to "provide the electricity to power public lighting in a city of 5,000 inhabitants." According to Global Construction Review, tenders for France's “Positive Energy” initiative have already been issued, and tests on the solar roadway panels will begin this spring, although the exact locations (and costs) for the project have not been specified. No word yet on whether these roads will be moose-friendly. More information about the solar roadway project can be found at the Wattway website.


Mallesham G.,Indian Institute of Chemical Technology | Balaiah S.,Indian Institute of Chemical Technology | Reddy M.A.,Indian Institute of Chemical Technology | Sridhar B.,Indian Institute of Chemical Technology | And 7 more authors.
Photochemical and Photobiological Sciences | Year: 2014

Six novel anthracene-oxadiazole derivatives, 4a (2-(4-(anthracen-9-yl) phenyl)-5-p-tolyl-1,3,4-oxadiazole), 4b (2-(4-(anthracen-9-yl)phenyl)-5-(4-tert- butylphenyl)-1,3,4-oxadiazole), 4c (2-(4-(anthracen-9-yl)phenyl)-5-(4- methoxyphenyl)-1,3,4-oxadiazole), 8a (2-(4-(anthracen-9-yl)phenyl)-5-m-tolyl-1, 3,4-oxadiazole), 8b (2-(3-(anthracen-9-yl)phenyl)-5-(4-tert-butylphenyl)-1,3,4- oxadiazole) and 8c (2-(3-(anthracen-9-yl)phenyl)-5-(3,4,5-trimethoxyphenyl)-1,3, 4-oxadiazole) have been synthesized and characterized for use as emitters in organic light emitting devices (OLEDs). They show good thermal stability (T d, 297-364 °C) and glass transition temperatures (Tg) in the range of 82-98 °C, as seen from the thermo gravimetric analysis and differential scanning calorimetric studies. The solvatochromism phenomenon and electrochemical properties have been studied in detail using UV-Vis absorption, fluorescence spectroscopy and cyclic voltammetry. TD-DFT calculations have been carried out to understand the electrochemical and photophysical properties. The spatial structures of 4b and 8c are further confirmed by X-ray diffraction analysis. Un-optimized non-doped electroluminescent devices were fabricated using these anthracene derivatives as emitters with the following device configuration: ITO (120 nm)/α-NPD (30 nm)/4a-4c or 8a-8c (35 nm)/BCP (6 nm)/Alq3 (28 nm)/LiF (1 nm)/Al (150 nm). Among all the six compounds, 8a displays the maximum brightness of 1728 cd m-2 and current efficiency 0.89 cd A-1. Furthermore, as an electron transporter, 8a exhibited superior performance (current efficiency is 11.7 cd A-1) than the device using standard Alq3 (current efficiency is 8.69 cd A-1), demonstrating its high potential for employment in OLEDs. These results indicate that the new anthracene-oxadiazole derivatives could play an important role in the development of OLEDs. This journal is © The Royal Society of Chemistry and Owner Societies.

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