Photovoltaic performance of long-chain poly(triphenylamine-phenothiazine) dyes with a tunable π-bridge for dye-sensitized solar cells

Abstract

A set of conjugated polymers based on poly(triphenylamine-phenothiazine) with carboxylic acid side groups have been synthesized and utilized as sensitizers for dye-sensitized solar cells (DSSCs). The polymers feature a conjugated side-chain consisting of thiophene unit (PPAT4), alternating with either a 3, 4-ethylenedioxythiophene (EDOT, PPAT5) or an EDOT-thiophene (PPAT6) as the π-bridge. This 10 methodology constitutes a consolidated step to adjust the molecular HOMO and LUMO energy levels of the dyes, hence red-shifting and broadening the absorption spectra in a conjugated polymer. Comparing with the model compound (PAT), the polymers exhibit a higher molar extinction coefficient throughout the visible region, and hence a better photovoltaic performance as using I -/I 3 electrolyte for DSSCs. Interestingly, depending on Suzuki coupling reaction, we get a fairly high degree of polymerization (DP 15 are 58, 46, 38 for PPAT4, PPAT5 and PPAT6, respectively) based on the three polymers. More uplifting is that when using the high DP polymers as sensitizers, photoelectrochemical tests based on the DSSCs format demonstrate a power conversion efficiency of 4.7%, 3.7% and 4.1% for PPAT4, PPAT5 and PPAT6, respectively, under the illumination of AM1.5G, 100 mW/cm 2 . This presented a considerably high photo-to-electric conversion efficiency in polymer dye-sensitized solar cells, overrating all polymer 20 dye sensitized solar cells previously disclosed.PPAT6 is on the ICT absorption peaks while PPAT4 and PPAT5 are both on π-π* transitions absorption peaks. This effect is probably related to the increasing extent of π-bridge of PPAT6 and consequently increased the HOMO level and ultimately narrowed the band-gap.

Tunable Electronic Memory Performances Based on Poly(Triphenylamine) and Its Metal Complex via a SuFEx Click Reaction

“…To achieve such ag oal, we chose triphenylamine (TPA) decorated with an azobenzene group as am onomer for the further condensation polymerization to form al ong-chain polymer structure. [11] The previous work showedt hat poly(triphenylamine) (PTPA) has ag reat potentialf or using in memory devicef abrication. [12] Due to its excellent thermal stability andalarge ON/OFFcurrent ratio.…”

“…In this paper, we are interested in achieve a multilevel memory performance through the molecular splicing, such as a SuFEx click reaction. To achieve such a goal, we chose triphenylamine (TPA) decorated with an azobenzene group as a monomer for the further condensation polymerization to form a long‐chain polymer structure . The previous work showed that poly(triphenylamine) (PTPA) has a great potential for using in memory device fabrication .…”

Arylamine polymers prepared via facile paraldehyde addition condensation: an effective hole‐transporting material for perovskite solar cells

“…In PTAA, substituting methyl groups at the 2‐ and 6‐positions improves its solubility. The molecular design and facile synthesis of arylamine polymers remain a topic of research …”

An Efficient Aniline‐Based Co‐Sensitizer for High Performance N3‐Sensitized Solar Cells

“…In fact, DSSCs based on sensitization of a mesoporous TiO 2 using Ruthenium polypyridyl complexes attracted considerable interest among the researchers because of their good photophysical and electrochemical properties . However, there are several detrimental factors influencing the photovoltaic performance of the cells such as light havesting efficiency, dye aggregation and electron recombination resistance . In order to address these issues, several approaches are being attempted for the development of DSSCs with improved performance.…”