Cathode Interface Investigation In Polymer/Fullerene Based Organic Solar Cells

Abstract

The authors investigate the cathode interface effects in polymer/fullerene based solar cell by using LiF, Liq and/or Bphen as the interfacial layers. Enhanced carrier extracting is observed by using Liq as the electron transport layer. A maximum power conversion efficiency of 3.75% is obtained in the case of Liq, presenting a 14% enhancement compared with the device with LiF as the electron transport layer. A detailed analysis of the capacitance as function of frequency and bias yields information about interfacial charges transport as well as the extraction and accumulation of charges is carried out. Cole-Cole impedance plots illustrate the interfacial resistance of different cathode buffer layer based device. The device shows good charge transport and the photo-generated changes could be effectively collected by the electrode and less charge accumulation when Liq is uswed as the cathode buffer layer.