Integrating metalloporphycenes into p-type NiO-based dye-sensitized solar cells

Abstract

In the current work, we have explored a novel synthetic route towards metalated porphycenes and their use in p-type NiO-based dye-sensitized solar cells. Particular emphasis is placed on the influence that the relative positioning of the anchoring group exerts on the DSSC performance.Factors that favor dye-sensitized solar cells (DSSCs) as a key technology in solar-energy conversion schemes include low purity requirements and easy accessibility, low costs, fast processing, and simple up-scaling. DSSCs have been rendered even more attractive by recent progress in solid-state and flexible devices. 1,2 To date, record efficiencies as high as 13% have been reported for n-type DSSCs. 3 However, efficient p-type DSSCs, which complement n-type DSSCs in, for example, tandem configurations, are necessary for obtaining values beyond 13%, and are therefore the subject of intensive investigation. 4 Regardless of whether the semiconductor materials are n-or p-type, the chromophore attached to the semiconductor electrode is decisive in terms of light harvesting, charge transfer, and charge transport. Diverse organic or inorganic chromophores have recently been tested in both types of DSSCs. [5][6][7][8] Fine tuning synthetic parameters such as the metalation of the chromophore, the nature of the anchor, and the bridge that links the chromophore to the anchor, have made control over important characteristics like highly effective charge separation, reduced charge recombination, and long term stability possible. [9][10][11][12] Semiconductor nickel oxide (NiO) stands out as an electrode material for p-type DSSCs. 7,[13][14][15] This has triggered the design of novel light-harvesting and electron-accepting chromophores. 13 We have focused on porphycenes because of their similarity to porphyrins and phthalocyanines. 16,17 In contrast to the electrondonating features of porphyrins and phthalocyanines, which are widely used in n-type DSSCs, 8,18 porphycenes are strong electron acceptors, making them more suitable building blocks for p-type DSSCs. Only a few examples of the use of free-base porphycenes in solar energy devices are known to date. 19,20 We now report two major achievements. The first is the development of a new synthetic route to nickel porphycenes, which have barely been investigated previously. We have characterized the novel nickel porphycenes by physicochemical and computational techniques. Secondly, we have used these nickel porphycenes in p-type NiO-based DSSCs. We have been able to rationalize the overall performances in terms of the position and the nature of the anchor groups and, in turn, to establish new guidelines to designing novel electron acceptors.Three different nickel porphycenes were prepared -Scheme 1 -see ESI. † To obtain the target porphycenes, the 2,7,12,17-tetra-npropylporphycenato nickel (1) was chosen as starting material. Firstly, the peripheral alkyl chains ensure solubility in a wide variety of solvents. Secondly, the established chemistry of 1 allows the target featuring a vinyl group as a...

Optimizing CuO p-type dye-sensitized solar cells by using a comprehensive electrochemical impedance spectroscopic study

“…16 In the next section, we probe CuO films in a direct comparison with state-of-the-art NiO electrodes and bare FTO references. 30,44 To this end, we assembled sandwich devices, consisting of bare CuO and NiO electrodes deposited on FTO facing a standard Pt coated FTO electrode. A mixture of 1 M LiI/0.2 M I 2 in a 5 : 1 ratio in acetonitrile was used as electrolyte and the corresponding R rec s and C µ s are summarized in Fig.…”

Combining Electron‐Accepting Phthalocyanines and Nanorod‐like CuO Electrodes for p‐Type Dye‐Sensitized Solar Cells

“…In particular, we demonstrate for the first time that DSSCs based on nanorod-like CuO electrodes outperform those with nanoparticle-like CuO and perform in a manner similar to those with CuXO2. Concerning dyes for p-type DSSCs, a myriad of different organic and inorganic sensitizers including triphenylamines, [8] perylenediimides, [9] perylene-bithiophene-triphenylamine triads, [10] porphycenes, [11] and ruthenium complexes, [12] have been designed and probed. Notably, porphyrinoids have led to the most efficient n-type DSSCs up to date.…”

Combining Electron‐Accepting Phthalocyanines and Nanorod‐like CuO Electrodes for p‐Type Dye‐Sensitized Solar Cells

“…Concerning dyes for p-type DSSCs, a myriad of different organic and inorganic sensitizers including triphenylamines, [8] perylenediimides, [9] perylene-bithiophene-triphenylamine triads, [10] porphycenes, [11] and ruthenium complexes, [12] have been designed and probed. Notably, porphyrinoids have led to the most efficient n-type DSSCs up to date.…”