Quasi-intrinsic semiconducting state of titanyl-phthalocyanine films obtained under ultrahigh vacuum conditions

Abstract

We investigated electrical properties of titanyl-phthalocyanine ͑TiOPc͒ films under ultrahigh vacuum ͑UHV͒ conditions to avoid the influence of gas adsorption. The field-effect measurement revealed that TiOPc films exhibited an n-type semiconducting behavior in UHV. The electron mobility at room temperature was 9ϫ10 Ϫ6 cm 2 V Ϫ1 s Ϫ1 with activation energy of 0.20 eV. The conductivity and carrier density were 9ϫ10 Ϫ8 S cm Ϫ1 and 6ϫ10 16 cm Ϫ3 , respectively. A clear conversion from n-type to p-type behavior was observed when the film was exposed to oxygen. Strict control of atmosphere made it possible to obtain a quasi-intrinsic state where both p-and n-type conductions appeared simultaneously.

Reversible Conversion of the Majority Carrier Type in Solution‐Processed Ambipolar Quinoidal Oligothiophene Thin Films

“…[ 18 , 19 ] Conversion from n-type to p-type has been also observed in titanyl-phthalocyanine after exposition of the organic thin fi lm to oxygen. [ 20 ] Another method to selectively control the ambipolar transport has been the introduction of buffer layers in OFETs based on polythiophene/fullerene blends. [ 21 ] On the other hand, unipolarization from ambipolar p-type dominant to n-type behavior has been achieved by thermal annealing in OFETs based on both discotic swallow-tailed quaterrylene tetracarboxdiimide [ 22 ] and the dicyanomethylene-substitued quinoidal quaterthiophene (QQT(CN)4).…”

Organic Charge-transfer Salts and the Component Molecules in Organic Transistors

“…Some metal complexes show n-channel performance, though others show p-channel performance. Metal phthalocyanine (Pc) is a representative p-channel material, 2 but TiOPc shows n-channel behavior under high vacuum, 47 and perfluorinated Pc is a well-known n-channel material. 48 Ni and Pt make square-planar complexes, and crystals of 21 afford n-channel transistors.…”

Particle induced nuclear reaction calculations of Boron target nuclei

“…It is preferred because it gives effective successful results in the treatment of cancer. In order to be successful, a sufficient amount of 10 B must be selectively delivered to all tumor cells and enough thermal neutrons must be absorbed to cause lethal damage from the 10 B(n,α) 7 Li capture reactions [1][2][3][4][5]. After the absorption of the thermal neutron, two product nuclei (He and Li) occurs.…”