TY - JOUR
T1 - Control mechanisms for transport and nonlinear optical response in organic materials
T2 - A tale of twists and barriers
AU - Facchetti, Antonio
AU - Hutchison, Geoffrey R.
AU - Keinan, Shahar
AU - Ratner, Mark A.
N1 - Funding Information:
We are grateful to the NSF/MRSEC program for support through the Northwestern MRSEC (Grant DMR-0076077), and to the NASA Institute for Nanoelectronics and Computing (Award NCC 2-3163) for support. This paper is in honor of Tobin Marks – treasured friend, teacher, colleague, inspirer and leader. Tobin’s remarkable insights into how molecular matter behaves have been honored by many awards, but the coherence, creativity, breadth and depth of his science speak plainly for themselves.
PY - 2004/11/1
Y1 - 2004/11/1
N2 - Simple electronic structure models are used to address two significant challenges in organic materials chemistry, the design of chromophores for strong electro-optic response (and low-energy optical absorption), and the prediction of relative mobilities and charge injection barriers for conductive oligomers. For electro-optic response, we examine two chromophore classes where twisting around an inter-ring bond can tune the electronic structure from aromatic (zwitterionic) to quinoid (neutral). The calculated nonlinear response develops a very strong maximum (βμ ∼ 1500 ×10-30 esu) at twist angles near 80°. For the transport behavior, structure/function correlations are presented for three series of oligomers, based on calculations of bandwidths (as functions of geometry) and of reorganization energies. Transport type appears to be fixed less by these mobility factors than by the injection barriers. The simplest estimates for these Schottky-type barriers, using frontier orbital energies from density functional calculations, predict carrier n-type or p-type behavior remarkably well.
AB - Simple electronic structure models are used to address two significant challenges in organic materials chemistry, the design of chromophores for strong electro-optic response (and low-energy optical absorption), and the prediction of relative mobilities and charge injection barriers for conductive oligomers. For electro-optic response, we examine two chromophore classes where twisting around an inter-ring bond can tune the electronic structure from aromatic (zwitterionic) to quinoid (neutral). The calculated nonlinear response develops a very strong maximum (βμ ∼ 1500 ×10-30 esu) at twist angles near 80°. For the transport behavior, structure/function correlations are presented for three series of oligomers, based on calculations of bandwidths (as functions of geometry) and of reorganization energies. Transport type appears to be fixed less by these mobility factors than by the injection barriers. The simplest estimates for these Schottky-type barriers, using frontier orbital energies from density functional calculations, predict carrier n-type or p-type behavior remarkably well.
UR - http://www.scopus.com/inward/record.url?scp=14344258099&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14344258099&partnerID=8YFLogxK
U2 - 10.1016/j.ica.2004.06.061
DO - 10.1016/j.ica.2004.06.061
M3 - Article
AN - SCOPUS:14344258099
SN - 0020-1693
VL - 357
SP - 3980
EP - 3990
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
IS - 13
ER -