TY - JOUR
T1 - Benzo[1,2-b:6,5-b′]dithiophene(dithiazole)-4,5-dione derivatives
T2 - Synthesis, electronic properties, crystal packing and charge transport
AU - Getmanenko, Yulia A.
AU - Fonari, Marina
AU - Risko, Chad
AU - Sandhu, Bhupinder
AU - Galán, Elena
AU - Zhu, Lingyun
AU - Tongwa, Paul
AU - Hwang, Do Kyung
AU - Singh, Sanjeev
AU - Wang, He
AU - Tiwari, Shree Prakash
AU - Loo, Yueh Lin
AU - Brédas, Jean Luc
AU - Kippelen, Bernard
AU - Timofeeva, Tatiana
AU - Marder, Seth R.
PY - 2013/2/21
Y1 - 2013/2/21
N2 - A series of dihalo- and bis-aroyl-substituted benzo[1,2-b:6,5-b′] dithiophene-4,5-diones were synthesized, and their electronic, electrochemical, and electrical properties investigated. Synthetic strategies to increase (i) the conjugation length of the base molecular structure-through introduction of thiophene units bearing electronically neutral substituents (hydrogen or alkyl groups) or strong electron-withdrawing pentafluorobenzoyl group(s)-and (ii) the electron affinity-by moving to a benzo[1,2-d:4,3-d′]bis(thiazole)-4,5- dione structure-were developed. Molecular packing in the single crystal was studied by single-crystal X-ray structural analysis, and this information was subsequently used in the determination of the electronic band structures, densities of states (DOS), effective transfer integrals, and effective charge-carrier masses via density functional theory (DFT) methods. The charge-carrier transport properties of the benzo[1,2-b:6,5-b′]dithiophene- 4,5-dione and benzo[1,2-d:4,3-d′]bis(thiazole)-4,5-dione derivatives were investigated through the fabrication and characterization of organic field-effect transistors (OFETs) via both solution-processed and vacuum-deposited films. 2,7-Bis-pentafluorobenzoyl-benzo[1,2-b:6,5-b′] dithiophene-4,5-dione (10a) exhibited field-effect behavior with an average electron mobility μe = 4.4 (±1.7) × 10-4 cm2 V-1 s-1 when the active layer was vacuum-deposited, and a larger μe= 6.9 × 10-3 cm2 V-1 s-1 when the active layer was solution-processed. These results are in stark contrast with the DFT-determined electronic band structure and effective mass, which indicate that the material possesses good intrinsic charge-carrier transport characteristics. The combined results reveal the importance of thin-film processing and that further processing refinements could lead to improved device performance. Only one material with benzo[1,2-d:4,3-d′]bis(thiazole)-4,5-dione core, 2,7-bis-(4-n-hexyl-thiophene-2-yl)-benzo[1,2-d:4,3-d′]bis(thiazole)-4, 5-dione (19d), showed average μe = 8.2 × 10-5 cm2 V-1 s-1 in OFET with solution-processed active layer. Unexpectedly, measurable hole transport was observed for 2,7-bis-(5-n-nonyl-thiophen-2-yl)-benzo[1,2-b:6,5-b′]dithiophene-4, 5-dione (19b) (μh = 8.5 × 10-5 cm2 V-1 s-1) and 2,6-bis-(thiophen-2-yl)-3,5-di-n-hexyl-4H- cyclopenta[1,2-b:5,4-b′]dithiophen-4-one (30a) (μh = 3.7 × 10-4 cm2 V-1 s-1).
AB - A series of dihalo- and bis-aroyl-substituted benzo[1,2-b:6,5-b′] dithiophene-4,5-diones were synthesized, and their electronic, electrochemical, and electrical properties investigated. Synthetic strategies to increase (i) the conjugation length of the base molecular structure-through introduction of thiophene units bearing electronically neutral substituents (hydrogen or alkyl groups) or strong electron-withdrawing pentafluorobenzoyl group(s)-and (ii) the electron affinity-by moving to a benzo[1,2-d:4,3-d′]bis(thiazole)-4,5- dione structure-were developed. Molecular packing in the single crystal was studied by single-crystal X-ray structural analysis, and this information was subsequently used in the determination of the electronic band structures, densities of states (DOS), effective transfer integrals, and effective charge-carrier masses via density functional theory (DFT) methods. The charge-carrier transport properties of the benzo[1,2-b:6,5-b′]dithiophene- 4,5-dione and benzo[1,2-d:4,3-d′]bis(thiazole)-4,5-dione derivatives were investigated through the fabrication and characterization of organic field-effect transistors (OFETs) via both solution-processed and vacuum-deposited films. 2,7-Bis-pentafluorobenzoyl-benzo[1,2-b:6,5-b′] dithiophene-4,5-dione (10a) exhibited field-effect behavior with an average electron mobility μe = 4.4 (±1.7) × 10-4 cm2 V-1 s-1 when the active layer was vacuum-deposited, and a larger μe= 6.9 × 10-3 cm2 V-1 s-1 when the active layer was solution-processed. These results are in stark contrast with the DFT-determined electronic band structure and effective mass, which indicate that the material possesses good intrinsic charge-carrier transport characteristics. The combined results reveal the importance of thin-film processing and that further processing refinements could lead to improved device performance. Only one material with benzo[1,2-d:4,3-d′]bis(thiazole)-4,5-dione core, 2,7-bis-(4-n-hexyl-thiophene-2-yl)-benzo[1,2-d:4,3-d′]bis(thiazole)-4, 5-dione (19d), showed average μe = 8.2 × 10-5 cm2 V-1 s-1 in OFET with solution-processed active layer. Unexpectedly, measurable hole transport was observed for 2,7-bis-(5-n-nonyl-thiophen-2-yl)-benzo[1,2-b:6,5-b′]dithiophene-4, 5-dione (19b) (μh = 8.5 × 10-5 cm2 V-1 s-1) and 2,6-bis-(thiophen-2-yl)-3,5-di-n-hexyl-4H- cyclopenta[1,2-b:5,4-b′]dithiophen-4-one (30a) (μh = 3.7 × 10-4 cm2 V-1 s-1).
UR - http://www.scopus.com/inward/record.url?scp=84876940211&partnerID=8YFLogxK
U2 - 10.1039/c2tc00805j
DO - 10.1039/c2tc00805j
M3 - Article
AN - SCOPUS:84876940211
SN - 2050-7534
VL - 1
SP - 1467
EP - 1481
JO - JOURNAL OF MATERIALS CHEMISTRY C
JF - JOURNAL OF MATERIALS CHEMISTRY C
IS - 7
ER -