Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription COMMUNICATION Combining novel electron-accepting phthalocyanines and nanorod-like CuO electrodes for p-type dye-sensitized solar cellsOliver Langmar, [a] Carolina R. Ganivet, [b] Annkatrin Lennert, [a] Rubén D. Costa, [a] Gema de la Torre, [b] Tomás Torres, [b] and Dirk M. Guldi [a] Abstract: In the current work, a novel route for the synthesis of two electron-accepting phthalocyanines featuring linkers with different length as sensitizers for p-type dye-sensitized solar cells are reported. Importantly, our devices -based on novel nanorod-like CuO photocathodes -feature efficiencies of 0.191%, which are to date the highest values ever reported for CuO-based DSSCs.

aWe introduce a novel and comprehensive approach for the evaluation and interpretation of electrochemical impedance spectroscopy (EIS) measurements in p-type DSSCs. In detail, we correlate both the device performance and EIS figures-of-merit of a series of devices in which, the calcination temperature, film thickness, and electrolyte concentration have been systematically modified. This new approach enables the separation of the different processes across the dye/semiconductor/electrolyte interface, namely the unfavorable charge recombination and the favorable electron injection/regeneration processes. In addition, studies on non-sensitized CuO and NiO electrodes provide insights into their affinity towards a reaction with the electrolyte -CuO is far less reactive towards the polyiodide species. Overall, this work underlines the superior features of CuO with respect to NiO for p-DSSCs and demonstrates a comprehensive optimization of the CuO-based DSSCs with respect to the device architecture by the aid of EIS analysis.

Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription COMMUNICATION Combining novel electron-accepting phthalocyanines and nanorod-like CuO electrodes for p-type dye-sensitized solar cellsOliver Langmar, [a] Carolina R. Ganivet, [b] Annkatrin Lennert, [a] Rubén D. Costa, [a] Gema de la Torre, [b] Tomás Torres, [b] and Dirk M. Guldi [a] Abstract: In the current work, a novel route for the synthesis of two electron-accepting phthalocyanines featuring linkers with different length as sensitizers for p-type dye-sensitized solar cells are reported. Importantly, our devices -based on novel nanorod-like CuO photocathodes -feature efficiencies of 0.191%, which are to date the highest values ever reported for CuO-based DSSCs.Current developments in p-type DSSCs focuses on exploring novel electrodes and electron acceptors. [1,2] Concerning the former, the most prominent material has been nickel(II) oxide (NiO), despite drawbacks such as low transparency, electrode thickness, and low conductivity. [2] To tackle some of the aforementioned bottlenecks, the preparation of binary NiXO semiconductors, where X is cobalt, have recently evolved as a powerful approach.[3] A viable alternative is based on the long overlooked copper(II) oxide (CuO), whose films feature higher conductivity, better charge carrier mobility, and comparable valence band energy relative to NiO films. [4,5] Still, the most recent report on CuO based p-type DSSCs is dated from 2008.[6] Very likely, state-of-the-art efficiencies as low as 0.011% resulted in a moderate interest. Recent improvements in the field of CuO based p-type DSSCs are due to the use of copper delafossite (CuXO2) electrodes with X being aluminum, chromium, or gallium.[ [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. [13,14] Key merits of porphyrins, and specially of their synthetic related phthalocyanines , (Pcs), [15,16] are their exceptional light-harvesting features and their facile functionalization with either electrondonors or electron-acceptors, underlining their potential for DSSCs. In light of the latter, tuning the physicochemical features of phthalocyanines towards new electron-accepting dyes [17,18] by means of placing electron-withdrawing substituents at their periphery, complements, in the current work, our research regarding nanorod-like CuO electrodes. ; ii) IBX, DMSO/THF; iii) H3NSO3/H2O followed by NaClO2; iv) propargyl alcohol, Pd(PPh3)2Cl2, CuI, NEt3, THF Notably, the synergy of nanorod-like CuO DSSCs and electronaccepting Pcs enables the construction of p-DSSCs with efficiencies as high as 0.103% and 0.191% with iodine-and cobalt-based electrolytes, respectively. The latter represents...

Herein, the synthesis of a new family of squaraines (SQs) and their application in p-type dye-sensitized solar cells (DSSCs) is presented. In particular, two sets of SQs were designed featuring either two or four anchoring carboxylic groups combined with either oxygen or dicyanovinyl central groups. The SQs were characterized by using a joint theoretical, photophysical, and electrochemical approach. Importantly, the presence of different central groups forces a frozen cis (dicyanovinyl group) or a trans (oxygen group) SQ conformation. Based on the latter, the current work enables a direct comparison between cis and trans isomers as well as the impact of a different number of anchors. Considering their electron-accepting and light-harvesting character, they were tested in NiO-based DSSCs. Photocurrent-voltage, incident photon-to-current conversion efficiency (IPCE), and electrochemical impedance spectroscopy measurements were performed. By virtue of their different symmetry, stereochemistry, and number of carboxylic groups, altered adsorption behavior onto NiO electrodes as well as diverse charge injection and charge recombination dynamics were noted under operation conditions. SQs with four linkers in a frozen cis isomerism show the best charge collection properties among the investigated SQs, providing a valuable guideline for the molecular design of future SQs for p-type DSSCs. In addition, we assembled tandem DSSCs featuring SQ/NiO photocathodes and N719/TiO photoanodes. The IPCE of the resulting tandem DSSCs implies light harvesting throughout most of the visible part of the solar spectrum owing to the complementary absorption features of SQ and N719.

We designed and synthesized as eries of novel electron-accepting zinc(II)phthalocyanines (ZnPc) and probed them in p-type dye sensitized solar cells (p-DSSCs) by using CuO as photocathodes.Byrealizing the right balance between interfacial charge separation and charge recombination, optimizedf ill factors (FFs) of 0.43 were obtained. With ac ontrol over fill factors in p-DSSCs in hand we turned our attemtion to t-DSSCs,inw hichwecombined for the first time CuO-based p-DSSCs with TiO 2 -based n-DSSCs using ZnPc and N719. In the resulting t-DSSCs,the V OC of 0.86 Visthe sum of those found in p-and n-DSSCs,w hile the FF remains around 0.63. It is only the smaller J sc sint-DSSCs that limits the efficiency to 0.69 %.