TY - JOUR

T1 - Excitation dynamics in α-sexithiophene single crystals and UHV-grown films

AU - Hopmeier, M.

AU - Marks, R. N.

AU - Michel, Rudi H.

AU - Muccini, M.

AU - Murgia, M.

AU - Zamboni, R.

AU - Taliani, C.

AU - Horowitz, G.

AU - Garnier, F.

AU - Oestreich, Michael

AU - Mahrt, Rainer E.

N1 - Funding information: This work was supported by the European Community (SELOA and LEDFOS), Sonderforschun-gsbereich 383, the Volkswagenstiftung and the Deutsche Forschungsgemeinschaft. We would like to thank Prof. H. Bassler and Prof. W.W. Ruble for fruitful and stimulating discussions.

PY - 1998/2

Y1 - 1998/2

N2 - We have investigated the disorder-determined optical properties of α-sexithiophene by comparing measurements of an evaporated film and a single crystal. We observed for the first time sharp lines in absorption and photoluminescence from both samples representing the intrinsic electronic properties of the material. The time-integrated emission spectra of both samples are dominated by radiative trap emission, which is more pronounced in the film due to the higher degree of disorder. Photoluminescence excitation and site-selective photoluminescence measurements show the different origin and character of the traps in the samples. We attribute the single crystal traps to the so-called X-traps while the nature of the traps in the film is still undetermined. Time-resolved photoluminescence measurements of the film show a fast transfer process of the sharp bulk emitters to the unstructured trap emission within the first 50 ps after excitation. A comparable process is observable in the single crystal, showing a slower dynamics due to lower trap density.

AB - We have investigated the disorder-determined optical properties of α-sexithiophene by comparing measurements of an evaporated film and a single crystal. We observed for the first time sharp lines in absorption and photoluminescence from both samples representing the intrinsic electronic properties of the material. The time-integrated emission spectra of both samples are dominated by radiative trap emission, which is more pronounced in the film due to the higher degree of disorder. Photoluminescence excitation and site-selective photoluminescence measurements show the different origin and character of the traps in the samples. We attribute the single crystal traps to the so-called X-traps while the nature of the traps in the film is still undetermined. Time-resolved photoluminescence measurements of the film show a fast transfer process of the sharp bulk emitters to the unstructured trap emission within the first 50 ps after excitation. A comparable process is observable in the single crystal, showing a slower dynamics due to lower trap density.

KW - Oligothiophene

KW - Optical properties

KW - Structural disorder

KW - Time-resolved photoluminescence

UR - http://www.scopus.com/inward/record.url?scp=4243668741&partnerID=8YFLogxK

U2 - 10.1016/S0022-2313(97)00229-9

DO - 10.1016/S0022-2313(97)00229-9

M3 - Article

AN - SCOPUS:4243668741

VL - 76-77

SP - 416

EP - 419

JO - Journal of Luminescence

JF - Journal of Luminescence

SN - 0022-2313

ER -