Conducting Polymers for Optoelectronic Devices and Organic Solar Cells: A Review

Abstract

In this review paper, we present a comprehensive summary of the different organic solar cell (OSC) families. Pure and doped conjugated polymers are described. The band structure, electronic properties, and charge separation process in conjugated polymers are briefly described. Various techniques for the preparation of conjugated polymers are presented in detail. The applications of conductive polymers for organic light emitting diodes (OLEDs), organic field effect transistors (OFETs), and organic photovoltaics (OPVs) are explained thoroughly. The architecture of organic polymer solar cells including single layer, bilayer planar heterojunction, and bulk heterojunction (BHJ) are described. Moreover, designing conjugated polymers for photovoltaic applications and optimizations of highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy levels are discussed. Principles of bulk heterojunction polymer solar cells are addressed. Finally, strategies for band gap tuning and characteristics of solar cell are presented. In this article, several processing parameters such as the choice of solvent(s) for spin casting film, thermal and solvent annealing, solvent additive, and blend composition that affect the nano-morphology of the photoactive layer are reviewed.

Influence of Fluorine Substitution on the Optical, Thermal, Electrochemical and Structural Properties of Carbazole-Benzothiadiazole Dicarboxylic Imide Alternate Copolymers

“…The organic layer collected and dried over MgSO 4 and the solvent concentrated to afford the product which was purified by vacuum distillation and gave 1 as a yellow oil (59.30 g, 245 mmol, 82% yield) [45]. 1 The mixture was stirred for 3h at 20-30 • C. Then, the mixture was poured into ice and upon melting of the ice a yellow precipitate filtrated and was washed thoroughly with deionized H 2 O. The product recrystallized from methanol to afford 2 as yellow crystals (32.50 g, 98 mmol, 91% yield) [46].…”

“…13 The system degassed under argon, anhydrous toluene (100 mL) was added and heated at 115 • C for 24 h. The flask cooled to RT and the volatiles removed to obtain the product which purified by column chromatography with gradient (petroleum ether, 0%-50% DCM) to obtain an orange solid and the product was further purified by recrystallization from methanol to afford 3 as orange crystals (9.10 g, 27 mmol, 90% yield) [47]. 1 H NMR (CDCl 3 , δ): 7.62 (dd, 2H, J = 1.0 Hz, 5.0 Hz), 7.56 (dd, 2H, J = 1.0 Hz, 4.0 Hz), 7.19 (dd, 2H, J = 4.0 Hz, 5.0 Hz). 13 Synthesis of 3 ,4 -diamino-2,2 :5,2"-terthiophene (4): EtOH (31 mL) and HCl (62 mL, 35%) were added to 3 (3.00 g, 8.86 mmol) in a flask.…”

“…Due to a significant increase in energy demand, as well as the growing concern regarding the adverse impacts of using fossil energy resources, the necessity for a sustainable and renewable alternate source of energy has gained importance in recent years [1][2][3][4][5]. Photovoltaic technologies, which can directly harvest energy from sunlight, can be considered as a promising solution to address the growing global energy demand [6,7].…”

“…Zhang et al reported on poly(2-(5-(5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo[c] [1,2,5]thiadiazol-7yl)thiophen-2-yl)-9-octyl-9H-carbazole) (HXS-1) copolymer including 2,7-carbazole and 5,6-dialkoxy-2,1,3-benzothiadiazole [(OR) 2 BT] as an acceptor [32]. HXS-1 blended with PC 71 BM exhibited a PCE of 5.4%.…”

“…HXS-1 blended with PC 71 BM exhibited a PCE of 5.4%. Iraqi et al designed and synthesised three copolymers, poly [9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl-alt-(5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole)-5,5-diyl] (PCDTBT-8), poly[9-(heptadecan-9-yl)-9H-carbazole-2,7-diyl-alt-(5,6-bis(octyloxy)-4,7-di(2,2 -bithiophen-5-yl)benzo [c] [1,2,5]thiadiazole)-5,5-diyl] (PCDT2BT-8) and PCDTBT based on 2,7-carbazole flanked by thienyl or bithienyl units as donor units and BT or (OR) 2 BT as acceptor moieties. PCDTBT that blended with PC 71 BM delivered the highest PCE of 4.30% [33].…”