Hiroshi Kageyama

High performance organic photovoltaic devices using amorphous molecular materials with high charge-carrier drift mobilities

pn-Heterojunction organic photovoltaic devices (OPVs) using amorphous molecular materials with high hole drift mobilities of 10−2u2002cm2u2009V−1u2009s−1, tris[4-(2-thienyl)phenyl]amine and tris[4-(5-phenylthiophen-2-yl)phenyl]amine, as electron donors and fullerene as an electron acceptor were fabricated. In spite of the use of amorphous materials instead of crystalline materials, the devices exhibited high performance with fill factors of 0.62–0.71 and power conversion efficiencies of 1.5%–1.7% under air-mass 1.5 G illumination at an intensity of 100u2002mWu2009cm−2.

Organic Photovoltaic Devices Using an Amorphous Molecular Material With High Hole Drift Mobility, Tris[4-(2-thienyl)phenyl]amine

A planar p-n heterojunction organic photovoltaic (OPV) device using an amorphous molecular material with a high hole drift mobility of 1.1 × 10-2 cm2/V·s at an electric field of 1.0 × 105 V/cm at 293 K, tris[4-(2-thienyl)phenyl]amine (TTPA), as an electron donor, and C60, as an electron acceptor, indium-tinoxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(4-styrene sulfonate) (PEDOT:PSS) (ca.30 nm)/TTPA (30 nm)/C60 (40 nm)/LiF (0.1 nm)/Al (150 nm), exhibited high performance with a fill factor of 0.62 and a power conversion efficiency (PCE) of 1.5 % under air-mass 1.5G illumination at an intensity of 100 mW/cm2. A p-i-n-type OPV device having a mixed interlayer of TTPA and C60, ITO/PEDOT (ca.30 nm)/TTPA (27 nm)/TTPA:C60 (1:4 molar ratio, 20 nm)/C60 (23 nm)/LiF (0.1 nm)/Al (100 nm), exhibited higher performance with a PCE of 1.8% under the same irradiation conditions. A bulk p-n heterojunction OPV devices fabricated by spin coating from solution of TTPA and [6,6]-phenyl-C61-butyric acid methyl ester ([6,6]-PCBM), ITO/PEDOT:PSS (ca. 30 nm)/TTPA:[6,6]-PCBM (1:4 molar ratio, ca. 73 nm)/LiF (0.1 nm)/Al (100 nm), exhibited a PCE of 1.3%. The high performance of the present devices is attributed to the high charge-carrier mobilities of the materials and the relatively high ionization potential of TTPA.

Small molecular weight materials for (opto)electronic applications: overview

Abstract: This chapter gives an overview of organic materials, focusing on molecular materials for use in optoelectronic devices such as organic photoreceptors, organic photovoltaic devices (OPVs), and organic light-emitting diodes (OLEDs). A description of the historical development of organic optoelectronics is provided. This is followed by a review of the principles and operation processes involved in such optoelectronic devices and the molecular materials for use in such devices. Finally, device structures and performance are discussed.

Performance of Organic Light-Emitting Diodes Using an Emissive Material with High Hole Drift Mobility

This study focuses on the performance of organic light-emitting diodes (OLEDs) using an emissive material with high hole drift mobility, tris[4-(5-phenylthiophen- 2-yl)]amine (TPTPA), which exhibits the highest level of hole drift mobility (1.0 × 10−2 cm2 V−1 s−1) among those reported for organic disordered systems. Clear blue emission was observed from TPTPA which was used as the hole transporting and emissive layer in the OLEDs. The maximum luminance of 1.2 × 104 cd/m2, and the maximum current efficiency of 3.9 cd/A were achieved. The short response times of electroluminescence (ca. 10 ns) were achieved under the application of rectangular-shaped voltages.