Extended π‐Bridge in Organic Dye‐Sensitized Solar Cells: the Longer, the Better?. Issue 7 (27th November 2013)

• Record Type: Journal Article
• Authors: Gao, Peng; Tsao, Hoi Nok; Yi, Chenyi; Grätzel, Michael; Nazeeruddin, Mohammad K.
• Is Part Of: Advanced energy materials. Volume 4:Issue 7(2014:Jul.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2013-11-27
• Subjects: Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201301485
• Languages: English
• ISSNs: 1614-6832

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The elongation of π‐conjugated bridges between the donor (D) and the acceptor (A) represents a feasible strategy towards enhancement of light‐harvesting in both breadth and depth of organic D‐π‐A dyes suitable for nanocrystalline TiO<sub>2</sub>‐based dye‐sensitized solar cells (DSSCs). Here, a series of organic dyes with elongating conjugated bridges is synthesized and characterized. DSSC devices employing a cobalt (II/III) redox electrolyte are fabricated using these dyes as light‐harvesting sensitizers. Compared to a dye with the 3, 4‐ethylenedioxythiophene (EDOT) linker (<bold>G188</bold>), the three counterparts with further extended π‐bridges present gradually red‐shifted electronic absorption spectra and a persistent decrease in oxidation potential. The photocurrent action spectra show that the extension of π‐conjugated bridges decreases the open‐circuit photovoltage. The best performance is shown in <bold>G268</bold> with a short‐circuit photocurrent density (<italic>J</italic><sub>sc</sub>) of 16.27 mA cm<sup>2</sup>, an open‐circuit photovoltage (<italic>V</italic><sub>oc</sub>) of 0.83 V, and a fill factor (<italic>FF</italic>) of 0.67, corresponding to an overall conversion efficiency of 9.24%. Unexpectedly, <bold>G270, which has</bold> with the longest π‐bridge<bold>, </bold> showed the lowest <italic>J</italic><sub>sc</sub>, <italic>V</italic><sub>oc</sub>, and efficiency.</p> </abstract>