Structure and properties of small molecule-polymer blend semiconductors for organic thin film transistors.
A comprehensive structural and electrical characterization of solution-processed blend films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) semiconductor and poly(alpha-methylstyrene) (PalphaMS) insulator was performed to understand and optimize the blend semiconductor films, which are very attractive as the active layer in solution-processed organic thin-film transistors (OTFTs). Our study, based on careful measurements of specular neutron reflectivity and grazing-incidence X-ray diffraction, showed that the blends with a low molecular-mass PalphaMS exhibited a strong segregation of TIPS-pentacene only at the air interface, but surprisingly the blends with a high molecular-mass PalphaMS showed a strong segregation of TIPS-pentacene at both air and bottom substrate interfaces with high crystallinity and desired orientation. This finding led to the preparation of a TIPS-pentacene/PalphaMS blend active layer with superior performance characteristics (field-effect mobility, on/off ratio, and threshold voltage) over those of neat TIPS-pentacene, as well as the solution-processability of technologically attractive bottom-gate/bottom-contact OTFT devices.
Kang
Jihoon
J
Department of Chemistry, Seoul National University, Seoul, 151-747, Korea.
Shin
Nayool
N
Jang
Do Young
DY
Prabhu
Vivek M
VM
Yoon
Do Y
DY
D017646:Organosilicon Compounds / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013343:Styrenes / Q000737:chemistry; D014173:Transistors, Electronic; D014961:X-Ray Diffraction
D017646:Organosilicon Compounds; D011137:Polystyrenes; D013343:Styrenes; C522282:bis(triisopropylsilylethynyl)pentacene; C027142:vinyltoluene