A Stable Panchromatic Green Dual Acceptor, Dual Donor Organic Dye for Dye-Sensitized Solar Cells

Abstract

A novel organic sensitizer (AP3) with dual donors and dual anchor-acceptors based on an electron deficient thieno [3,4-b]pyrazine (TPz) π-bridge was synthesized, which shows an impressively high J sc of 17.6 mA/cm 2 when cosensitized with D35 (12.4 mA/cm 2 as a single dye). Device power conversion efficiencies were observed at 7.5% under full sun intensity and in excess of 10% under reduced sun intensity. This novel dye design approach allows for devices showing photostability beyond 500 h for continuous irradiation and a tunable dye structure with an incident power conversion efficiency breadth reaching 800 nm from a simple-to-synthesize organic dye. Dye characterization with cyclic voltammetry, solution and film absorption, and computational analysis are all presented. Additionally, device characterization was performed through IV curves, IPCE, electron lifetime measurements, transient absorption spectroscopy, and current dynamic measurements at varying sun intensities to better understand the origin of the high device power conversion efficiencies as well as the interactions of AP3 and D35 in DSC devices.

Near‐Infrared‐Absorbing Metal‐Free Organic, Porphyrin, and Phthalocyanine Sensitizers for Panchromatic Dye‐Sensitized Solar Cells

“…Recently,T Pz was reporteda sauniques caffold for aD D-p-AA structured dye (AP3;T PA donor,b enzoic acid acceptor). [43] AP3 demonstrated ab road IPCE up to 800 nm (IPCE peak = 50 %, 5.0 %P CE). Through co-sensitizationw ith ab road-band-gap dye (D35, see Ref.…”

“…To the best of our knowledge, this represents the highest PCE of any precious‐metal‐free dye utilizing photons at 900 nm. Recently, TPz was reported as a unique scaffold for a DD–π–AA structured dye (AP3; TPA donor, benzoic acid acceptor) . AP3 demonstrated a broad IPCE up to 800 nm (IPCE peak=50 %, 5.0 % PCE).…”

“…Through co‐sensitization with a broad‐band‐gap dye (D35, see Ref. for structure), the IPCE response increased to 85 % (17.6 mA cm −2 ) and the PCE to 7.5 %. An analogous dye, TP1, employed only a single benzoic acid moiety .…”

Titanium Dioxide Modifications for Energy Conversion: Learnings from Dye-Sensitized Solar Cells

“…These co-additives can be divided based on the chemical identity of anchoring group and their influence on the interface can be best studied through EIS and Titanium Dioxide -Material for a Sustainable Environmentelectron lifetime measurements. Since aggregation is a common phenomenon for mostly planar organic sensitizer including phthalocyanine and porphyrin, the effect of co-additives on aggregation can be studied by simple current dynamic measurements at different light intensities [102,103].…”

“…Under optimum conditions, CDCA is generally known to positively (downward) shift the conduction band of TiO 2 , increasing electron injection along with lower recombination losses thus enhancing both J sc and V oc. It should be noted that CDCA mainly serves the role of de-aggregating agent for organic, porphyrin and phthalocyanine sensitizers and a recombination blocking agent for Ru (II) sensitizers since latter dyes do not aggregate on TiO 2 [102]. In a recent study for ladder-like carbazole donor and cyanoacrylic acid (CA) anchor based D-A-π-A type dye, CDCA resulted in up to 9% enhancement in PCE when co-adsorbed with the dye [107].…”