Effect Of Electrode Modification On The Performance On Organic Solar Cells

Organic photovoltaics have been considered as a potential candidate for a low-cost ‘clean’ renewable energy source owing to superior properties of low weight, good mechanical flexibility and suitability for flexible mass production In this paper, we present a systematic investigation of the effect of electrode interface modification on the performance and stability of OPVs, the main research contents include three parts as follows:(1) In order to study the effect of organic and inorganic cathode interface layer on the performance and stability of OPVs. Six kinds of cathode interface layers, i.e. LiF, NaCl, NaCl/Mg, Alq3, BCP, TPBi, were inserted between the photoactive layer and an Al cathode. The results show that devices with these cathode interface layers all exhibite improved performance. Howerver, the devices with inorganic cathode interface layers exhibited better stability than those with organic cathode interface layers.(2) We present the effect of interface modification based on ITO flexible electrode on the performance of OPVs. Firstly, an UV-ozone treated thin Ag were inserted between the UV-ozone treated ITO anode and photoactive layer. Through optimizing the Ag thickness and UV-ozone treatment time, it is shown that the device with 1 min UV-ozone treated 1nm Ag achieved highest efficiency of 2.55%. Moreover, we also used the UV-ozone treated Ag(1 nm)/PEDOT:PSS or MoO3 composited anode interface layer modified ITO. The results show that device performance was further improved and highest efficiency is almost 3%, which increased by 35% as compared to the reference devices of PEDOT:PSS(MoO3). In addition, higher power conversion of efficiency(PCE) of 6.21% of flexible polymer solar cells based on PBDTTT-EFT: PC71 BM as photoactive layer was also obtained.(3) Effect of different interface modifications on Ag nanowires(Ag NWs) electrode were studied and efficient flexible polymer solar cell was achieved. Firstly, Ag NWs electrode were treated by UV-ozone and controlled treatment time. After treated by UV-ozone, Ag NWs film exhibits several promising characteristics, including inproved surface property and superior surface work function. Subsequently, PEDOT:PSS or MoO3 anode interface layer were inserted between the UV-ozone treated Ag NWs electrode and photoactive layer. Compared with the device without any interface modification(0.76%), the devices with Ag NWs(UV-ozone)/PEDOT:PSS(MoO3) showed higher efficiency of 2.77% and increased about 3.6 times. In addition, the PCE of 5.97% of flexible polymer solar cells based on PBDTTT-EFT:PC71BM as an photoactive layer was obtained.