Photovoltaic properties of photodiodes based on nano-TiO_2 and poly[2-methoxy,5-(2′-ethlhexyloxy)- p-phenylenevinylene] (MEH-PPV) composites are investigated. By comparing composite devices with the same weight of TiO_2 (nanoparticles and nanotubes):MEH-PPV, it was found that the device with TiO_2 nanotubes exhibited better performance. By further optimizing the weight radio of TiO_2 nano- tubes:MEH-PPV, we gained the device with a short circuit current density of 9.27 μA/cm2 with a light intensity of 16.7 mW/cm2 at the 500 nm wavelength, the highest open-circuit voltage of 1.1 V, and a photosensitivity of 332 at reverse bias of -0.6 V. The photosensitivity is improved by a factor of 33 compared with the undoped MEH-PPV device.
LI Yan HOU YanBing JIN Hui SHI QuanMin WANG Yan FENG ZhiHui
The carrier transport properties of the blends of the hole transport material poly(N-vinylcarbazole) (PVK) and the electron transport material tris (8-hydroxyquinolinolato) aluminumⅢ(Alq_3) are investigated at room temperature using steady-state and time-resolved transient photocurrent measurements as a function of doping concentration of Alq_3.Due to lower LUMO and higher HOMO energy level of Alq_3 than those of PVK,Alq_3 molecules may act as carrier trap states in PVK films at low concentration.However...
