An effective π-extended squaraine for solution-processed organic solar cells with high efficiency

Abstract

A π-extension strategy is an effective way for squaraines for achieving high-performance photovoltaic materials capable of showing much enhanced hole mobility.

Photovoltaic Devices Prepared through a Trihydroxy Substitution Strategy on an Unsymmetrical Squaraine Dye

“…Nevertheless, it is a little surprising that the photovoltaic performance of USQ‐4‐OH is inferior to that of USQ‐3‐OH (PCE: 6.07 vs. 5.67 %), despite the fact that USQ‐4‐OH possesses more −OH substituents than that of USQ‐3‐OH . The PCE value of 6.07 %, to the best of our knowledge, is one of the highest PCE values reported for SQ‐based BHJ‐OPV cells ,…”

“…With an increasing number of −OH substituents, the HOMO levels of the compounds will decrease slightly; interestingly, the trihydroxy‐substituted compound, USQ‐3‐OH , displays the highest photovoltaic performance of these three compounds, which should arise from the higher hole mobility and smaller phase separation of the USQ‐3‐OH :[6,6]‐phenyl‐C 71 ‐butyric acid methyl ester (PC 71 BM) blended photoactive film. It is noteworthy that the short‐circuit current ( J sc ) of the USQ‐3‐OH ‐based device could be as high as 14.95 mA cm −2 , which is the highest value reported for SQ‐based BHJ solar cells; the PCE of the USQ‐3‐OH ‐based device could also reach 6.07 %, which is one of the highest PCE values among SQ‐based BHJ solar cells reported, to date ,…”

Effect of Alkyl Chain Length on the Sensitizing Action of Substituted Non‐Symmetric Squaraines for p‐Type Dye‐Sensitized Solar Cells

“…The fulfilment of these requirements would allow an effective action of dye‐sensitization towards the solar radiation for wide bandgap semiconductors of p‐type. The choice of the class of squaraine dyes is motivated mainly by the versatility of their synthetic chemistryand by the characteristic red‐shifted absorption with respect to the dyes commonly employed as sensitizers of DSCs . This represents an added value of the squaraine in the perspective of developing and assembling t ‐DSCs with the two photoelectrodes sensitized by dyes with complementary absorption features.…”

Rational Design of 2D p–π Conjugated Polysquaraines for Both Fullerene and Nonfullerene Polymer Solar Cells

“…A breakthrough was made in 2008; Marks et al developed a new type of hydrazine end‐capped SQs as the donor materials in the bulk heterojunction (BHJ) OSCs, and an encouraging PCE of 1.24% was produced. Subsequently, the photovoltaic performance of SQs has been gradually elevated with further development of new material exploitation and device engineering . Thus far, PCEs over 7% have been demonstrated in both single‐junction and tandem BHJ devices merely with SQs as the donors .…”