Development of Polymer Acceptors for Organic Photovoltaic Cells

Abstract

This review provides a current status report of the various n-type polymer acceptors for use as active materials in organic photovoltaic cells (OPVs). The polymer acceptors are divided into four categories. The first section of this review focuses on rylene diimide-based polymers, including perylene diimide, naphthalene diimide, and dithienocoronene diimide-based polymers. The high electron mobility and good stability of rylene diimides make them suitable for use as polymer acceptors in OPVs. The second section deals with fluorene and benzothiadiazole-based polymers such as poly(9,9'-dioctylfluorene-co-benzothiadiazole), and the ensuing section focuses on the cyano-substituted polymer acceptors. Cyano-poly(phenylenevinylene) and poly(3-cyano-4-hexylthiophene) have been used as acceptors in OPVs and exhibit high electron affinity arising from the electron-withdrawing cyano groups in the vinylene group of poly(phenylenevinylene) or the thiophene ring of polythiophene. Lastly, a number of other electron-deficient groups such as thiazole, diketopyrrolopyrrole, and oxadiazole have also been introduced onto polymer backbones to induce n-type characteristics in the polymer. Since the first report on all-polymer solar cells in 1995, the best power conversion efficiency obtained with these devices to date has been 3.45%. The overall trend in the development of n-type polymer acceptors is presented in this review.

New poly(p-phenylenevinylene) derivatives containing isosorbide unit in the side-chain

“…Since then, enormous progress has been made in the macromolecular engineering of the !-conjugated polymers and in their uses as active materials in polymeric light-emitting diodes (PLEDs) [2][3][4][5][6]. These polymers are promising organic analogues of inorganic semi-conducting materials, and their exploitation in other electronic devices, such as thin-film transistors [7,8], photovoltaic cells [9,10], chemical sensors [11] and organic lasers [12] are currently expanding. The main advantages of using such functional polymers lie in their low production cost and easy processibility.…”

n-Type Electron-Accepting Materials for Organic Solar Cells (OSC)

“…The limited structural versatility of fullerenes also restricts the screening of better donor/acceptor pair with a limited pool of molecular candidates. In this context, non-fullerene acceptors with tunable absorption features, unlimited variations of chemical structures, and lower production cost, have attracted great attentions in the past decade [40]. There are two different types of non-fullerene acceptors in terms of the molecular sizes-namely, polymers and small molecules [40,41].…”

“…In this context, non-fullerene acceptors with tunable absorption features, unlimited variations of chemical structures, and lower production cost, have attracted great attentions in the past decade [40]. There are two different types of non-fullerene acceptors in terms of the molecular sizes-namely, polymers and small molecules [40,41]. Various organic semiconducting structures were proposed and tested as the electron-accepting materials in organic solar cells.…”

Azomethine naphthalene diimides as component of active layers in bulk heterojunction solar cells

“…In recent years, attention is paid to molecules which were created using donor-acceptor (D-A) strategy [12][13][14][15][16][17]. A number of electron acceptor building blocks were combined with donor building blocks to create a D-A molecules explored for organic photovoltaics [13,18].…”

“…The optimal band gaps for D-A molecules for high efficiency of OPVs are in the range of 1.2-1.7 eV and favorable HOMO/LUMO energetic levels to match with the LUMO level of the acceptor materials (fullerene derivatives) [13]. Among the currently investigated classes of materials to form acceptor building blocks, naphthalene diimide (NDI) have aroused a lot of attention due to its valuable physical and electronic properties [9,17,19]. NDIs are usually investigated for organic thin film transistors (OTFTs) [13,20].…”