Photocarriers generation process and photovoltaic effect in PPHT thin film Schottky barrier devices

摘要

Photogeneration process and photovoltaic effect ofAl/poly(3-phenylhydrazone thiophene) (PPHT)/ITO andIn/PPHT/ITO sand-wich devices were investigated by measuringsteady state photocurrent resulting from illuminating through theITO electrode. From the comparison of photoaction spectra of thedevice with the adsorption spectra of the PPHT layer, it wasobserved that PPHT forms Schottky barrier with In and Al andohmic contact with ITO. The voltage dependence of thephotocurrent in the vicinity of Vbi was measured at 1mW/cm2 ofthe incident illumination to give the open circuit voltage (Voc) andshort circuit photocurrent (Jsc). The photoaction spectra of thedevice also suggest that only light absorbed near the blockingcontact, i.e., at Al/PPHT, In/PPHT is effective in producingcarriers for external circuit. The dependence of the short circuitphotocurrent on the illumination intensity was also described indetail. Various photovoltaic parameter was also calculated fromthe current-voltage(J-V) characteristics of the open device underillumination through ITO. 999Elsevier science S.A. All rights reserved.