TY - JOUR
T1 - Zone-refinement effect in small molecule-polymer blend semiconductors for organic thin-film transistors
AU - Chung, Yeon Sook
AU - Shin, Nayool
AU - Kang, Jihoon
AU - Jo, Youngeun
AU - Prabhu, Vivek M.
AU - Satija, Sushil K.
AU - Kline, R. Joseph
AU - DeLongchamp, Dean M.
AU - Toney, Michael F.
AU - Loth, Marsha A.
AU - Purushothaman, Balaji
AU - Anthony, John E.
AU - Yoon, Do Y.
PY - 2011/1/26
Y1 - 2011/1/26
N2 - The blend films of small-molecule semiconductors with insulating polymers exhibit not only excellent solution processability but also superior performance characteristics in organic thin-film transistors (OTFTs) over those of neat small-molecule semiconductors. To understand the underlying mechanism, we studied triethylsilylethynyl anthradithiophene (TESADT) with small amounts of impurity formed by weak UV exposure. OTFTs with neat impure TESADT had drastically reduced field-effect mobility (<10-5 cm2/(V s)), and a disappearance of the high-temperature crystal phase was observed for neat impure TESADT. However, the mobility of the blend films of the UV-exposed TESADT with poly(R-methylstyrene) (PαMS) is recovered to that of a fresh TESADT-PαMS blend (0.040 cm2/(V s)), and the phase transition characteristics partly return to those of fresh TESADT films. These resultsarecorroboratedbyOTFTresultson"aged"TIPS-pentacene. These observations, coupled with the results of neutron reflectivity study, indicate that the formation of a vertically phase-separated layer of crystalline small-molecule semiconductors allows the impurity species to remain preferentially in the adjacent polymerrich layer. Such a "zone-refinement effect" in blend semiconductors effectively removes the impurity species that are detrimental to organic electronic devices from the critical charge-transporting interface region.
AB - The blend films of small-molecule semiconductors with insulating polymers exhibit not only excellent solution processability but also superior performance characteristics in organic thin-film transistors (OTFTs) over those of neat small-molecule semiconductors. To understand the underlying mechanism, we studied triethylsilylethynyl anthradithiophene (TESADT) with small amounts of impurity formed by weak UV exposure. OTFTs with neat impure TESADT had drastically reduced field-effect mobility (<10-5 cm2/(V s)), and a disappearance of the high-temperature crystal phase was observed for neat impure TESADT. However, the mobility of the blend films of the UV-exposed TESADT with poly(R-methylstyrene) (PαMS) is recovered to that of a fresh TESADT-PαMS blend (0.040 cm2/(V s)), and the phase transition characteristics partly return to those of fresh TESADT films. These resultsarecorroboratedbyOTFTresultson"aged"TIPS-pentacene. These observations, coupled with the results of neutron reflectivity study, indicate that the formation of a vertically phase-separated layer of crystalline small-molecule semiconductors allows the impurity species to remain preferentially in the adjacent polymerrich layer. Such a "zone-refinement effect" in blend semiconductors effectively removes the impurity species that are detrimental to organic electronic devices from the critical charge-transporting interface region.
UR - http://www.scopus.com/inward/record.url?scp=79851481324&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79851481324&partnerID=8YFLogxK
U2 - 10.1021/ja108772q
DO - 10.1021/ja108772q
M3 - Article
C2 - 21155572
AN - SCOPUS:79851481324
SN - 0002-7863
VL - 133
SP - 412
EP - 415
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 3
ER -