Polymers for electronics and spintronics

Abstract

This critical review is devoted to semiconducting and high spin polymers which are of great scientific interest in view of further development of the organic electronics and the emerging organic spintronic fields. Diversified synthetic strategies are discussed in detail leading to high molecular mass compounds showing appropriate redox (ionization potential (IP), electron affinity (EA)), electronic (charge carrier mobility, conductivity), optoelectronic (electroluminescence, photoconductivity) and magnetic (magnetization, ferromagnetic spin interactions) properties and used as active components of devices such as n- and p-channel field effect transistors, ambipolar light emitting transistors, light emitting diodes, photovoltaic cells, photodiodes, magnetic photoswitches, etc. Solution processing procedures developed with the goal of depositing highly ordered and oriented films of these polymers are also described. This is completed by the description of principal methods that are used for characterizing these macromolecular compounds both in solution and in the solid state. These involve various spectroscopic methods (UV-vis-NIR, UPS, pulse EPR), electrochemistry and spectroelectrochemistry, magnetic measurements (SQUID), and structural and morphological investigations (X-ray diffraction, STM, AFM). Finally, four classes of polymers are discussed in detail with special emphasis on the results obtained in the past three years: (i) high IP, (ii) high |EA|, (iii) low band gap and (iv) high spin ones.

Symmetrically Disubstituted Bithiophene Derivatives of 1,3,4-Oxadiazole, 1,3,4-Thiadiazole, and 1,2,4-Triazole – Spectroscopic, Electrochemical, and Spectroelectrochemical Properties

“…Band gap narrowing with simultaneous increase of IP is usually achieved by synthesizing donor/acceptor molecules of AD, DAD or ADA types or their polymeric analogues. 4,14,15 In these cases narrower band gap results from mesomeric effects, which are responsible for an increase of the double bond character between the donor and acceptor units. 1,16,17 The above outlined strategy can also be applied to the synthesis of molecules showing IP significantly higher than that of oligothiophenes.…”

“…[1][2][3][4][5][6][7][8][9][10][11] Appropriate functionalization of these compounds make them solution processable and allows for precise tuning of their electronic, spectroscopic, electrochemical and mechanical properties. For example, molecules exhibiting high electron affinity (|EA|>3.9 eV) due to their low lying LUMO level are good candidates for the fabrication of air operating n-channel FETs.…”

Spectroelectrochemistry of alternating ambipolar copolymers of 4,4′- and 2,2′-bipyridine isomers and quaterthiophene

“…Oligo-and polythiophene molecules are playing an important role in the field of organic electronics, on account of their advantageous electronic and optical properties [1,2]. In order to tailor their properties for specific applications, functionalization is an effective means to achieve this goal [3].…”

Recent Advances in Polymer Organic Light-Emitting Diodes (PLED) Using Non-conjugated Polymers as the Emitting Layer and Contrasting Them with Conjugated Counterparts

“…137 In addition, palladium black formed during polycondensation can be hard to remove completely. 132 Given that the vast majority of conjugated polymers are generated by transition-metal catalyzed coupling in which monomers containing aryl bromide are frequently employed, non-conjugated polymers, which are mainly synthesized by free-or living-radical polymerizations where no transition metals and halogens are involved, may have an advantage over the conjugated counterparts in this regard.…”

“…The analogous polymerization for conjugated polymers is the Grignard metathesis polymerization (GRIM) which shows quasi-living characters and is commonly used for preparing regioregular poly(3-hexylthiophene) (P3HT). 132 Both of these polymerization methods are able to produce block copolymers. 46,133 However, strongly nucleophilic organomagnesium species is inevitably present in GRIM, which severely limit the scope of monomers that can be polymerized, whereas radical polymerization is well known to have high functional group tolerance.…”