Development of naphtho[1,2-b:5,6-b′]dithiophene based novel small molecules for efficient bulk-heterojunction organic solar cells

Abstract

Two new small molecules with a rigid planar naphtho[1,2-b:5,6-b']dithiophene (NDT) unit were designed and synthesized. Solution processed bulk-hetereojunction organic solar cells based on blends of the small molecules and [6,6]-phenyl-C(71)-butyric acid methyl ester (PC(71)BM) exhibited promising photovoltaic device performance with a maximum power conversion efficiency up to 2.20% under the illumination of AM 1.5G, 100 mW cm(-2).

Naphthodithiophene-Based Semiconducting Materials for Applications in Organic Solar Cells

“…The bandgaps estimated from the absorption onsets are 1.99 and 2.02 eV for M6 and M7, respectively. Therefore, the incorporation of the triphenylamine has a negative effect on reducing the bandgap of these bithiazole-based semiconductors, which is contrary to the benzothiadiazole and naphtho[1,2-b:5,6-b′]dithiophene-based semiconductors M4 and M5 [78]. Film microstructure was investigated by X-ray di raction (XRD), and the di raction patterns indicate that the incorporation of triphenylamine leads to lower degree of ordering and enlarged π-π stacking distance for M7.…”

“…The rst naphtho[1,2-b:5,6-b′]dithiophene-containing organic semiconductors for OSCs were reported by Lee et al [78]. The semiconductors M4 and M5 contain thiophene-anked NDT as the electron donor unit and benzothiadiazole or triphenylamine-capped benzothiadiazole as the electron acceptor unit.…”

Naphthodithiophenes: Emerging Building Blocks for Organic Electronics

“…On the other hand, Dutta and co‐workers have also developed a series of NDT3‐based oligomers ( O4 – O7 ) with the D–A–D–A–D architecture, where benzo[ c ][1,2,5]thiadiazole (BTz), 2,2′‐bisthiadiazole, or thiazolo[5,4‐ d ]thiazole (TzTz) were employed as the A unit and triphenylamine or thiophene moieties as the outer D unit (Figure ) . The oligomers were examined as the active semiconducting material in p‐channel OFETs and as the p‐type semiconductor in the BHJ active layer combined with [6,6]‐phenyl‐C 71 ‐butyric acid methyl ester (PC 71 BM) or PC 61 BM in OPVs.…”

An Efficient Tin‐Free Route to Small Molecules Based on Silole‐Modified Pentathiophenes for Solution‐Processed Organic Solar Cells

“…Generally, a high-efficiency small-molecule donor should meet several key requirements, such as broad and strong absorption, matched energy levels with acceptors, planar structure for high hole mobility, excellent ability to form films, and miscibility with fullerene derivatives. [3] Because planar, rigid, fused rings can enhance charge-carrier mobility and broaden the absorption, [11] considerable effort has been devoted to introducing heteroarenes into p-conjugated polymers, [12][13][14] and using organic small-molecule [15][16][17][18] backbones as the electron-donating units of highly efficient donor materials. However, the introduction of a rigid fused ring frequently increases the tendency of the material to self-assemble into large domains, and reduces its capacity to form interpenetrating networks with fullerene derivatives, which can result in a low device short-circuit current (J sc ).…”