Easily Attainable Phenothiazine-Based Polymers for Polymer Solar Cells: Advantage of Insertion of S,S-dioxides into its Polymer for Inverted Structure Solar Cells

Abstract

Two donor− (D−) acceptor (A) type polymers based on a soluble chromophore of phenothiazine (PT) unit that is a tricyclic nitrogen−sulfur heterocycle, have been synthesized by introducing an electron-deficient benzothiadiazole (BT) building block copolymerized with either PT or phenothiazine-S,S-dioxide (PT-SS) unit as an oxidized form of PT. The resulting polymers, PPTDTBT and PPTDTBT-SS are fully characterized by UV−vis absorption, electrochemical cyclic voltammetry, Xray diffraction (XRD), and DFT theoretical calculations. We find that the maximum absorption of PPTDTBT is not only markedly red-shifted with respect to that of PPTDTBT-SS but also its band gap as well as molecular energy levels are readily tuned by the insertion of S,S-dioxides into the polymer. The main interest is focused on the electronic applications of the two polymers in organic field-effect transistors (OFETs) as well as conventional and inverted polymeric solar cells (PSCs). PPTDTBT is a typical p-type polymer semiconductor for OFETs and conventional PSCs based on this polymer and PC 71 BM show a power conversion efficiency (PCE) of 1.69%. In case of PPTDTBT-SS, the devices characteristics result in: (i) 1 order of magnitude higher hole mobility (μ = 6.9 × 10 −4 cm 2 V −1 s −1 ) than that obtained with PPTDTBT and (ii) improved performance of the inverted PSCs (1.22%), compared to its conventional devices. Such positive features can be accounted for in terms of closer packing molecular characteristics owing either to the effects of dipolar intermolecular interactions orientated from the sulfonyl groups or the relatively high coplanarity of PPTDTBT-SS backbone.

Random Terpolymer Designed with Tunable Fluorescence Lifetime for Efficient Organic/Inorganic Hybrid Solar Cells

“…[24][25][26] As a heterocyclic compound with electron-rich sulfur and nitrogen atoms, phenothiazine is proved to be a promising candidate in designing new co-polymers with to obtain high intramolecular charge transfer (ICT) abilities, owing to its 'butterfly' nonplanar geometry which can impede π-stacking congestion, achieving low cost and good solubility by introducing solubilizing units. [27][28][29] Besides, planar benzodithiophene (BDT) donor units also have been utilized to achieve smaller band gaps, deeper 4 highest occupied molecular orbital (HOMO) levels, and much more facile charge separation for PV applications. 30 …”

Novel pyran based dyes for application in dye sensitized solar cells

“…The pyran core is symmetrically linked to phenothiazine groups; phenothiazine is a heteroaromatic system characterized by a strong electron donor ability as a consequence of the presence of electron rich nitrogen and sulfur atoms contained in it. It has been widely in organic electronics as donor moiety in donor-acceptor molecular systems in the field of bulk heterojunction solar cells [23][24][25] and DSSCs [26][27][28][29]. In the present work, phenothiazine groups are M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 functionalized with two acrylic acid moieties for allowing binding to the TiO 2 surface in DSSC fabrication.…”

Improved Solubility and Characterization of Photovoltaic Properties D/A Copolymers based on Rigid Structure of Phenothiazine-Quinoxaline

“…이러한 효율은 기존 실리콘태양전지에 비해 매우 낮은 수준이며 상업적으로 성공하 기 위해선 최소 10%대 이상의 효율을 나타내어야 하는 것으로 보고되고 있다 [8][9][10][11]. 이에 따라 높은 광전변환효율과 안정성 을 확보하기 위해 전자주개 물질로 공액 고분자와 전자받개 물질로 fullerene의 유도체인 PCBM을 혼합한 이종접합형태 (bulkheterojunction, BHJ)구조에 대한 개발이 활발히 진행 중이 며, 8-10%대의 고효율의 구조도 보고되고 있다 [12][13][14].…”