Impact of Buffer Interlayer on the Performance of Heterojunction Organic Photovoltaic Devices

The CuPc/buffer interlayer/C60heterojunction organic photovoltaic devices are fabricated by inserting a MoO3or RB interlayer and investigated the impact of buffer interlayer on the performance of heterojunction organic photovoltaic devices.The results suggest that OPV with the buffer interlayer has higher open-circuit voltage and power conversion efficiency,lower short-circuit current density and fill factor.The open-circuit voltage increases from 0.39Vto 0.58Vand 0.55V,respectively,and the power conversion efficiency reaches 0.44%,in comparison with a power conversion efficiency of 0.36%for OPV without interlayer.The short-circuit current density decreases from 1.92mA/cm2 to 1.77mA/cm2 and 1.81mA/cm2,and from 0.48to 0.43and 0.44in fill factor,respectively.Further research shows that the short-circuit current density strongly depends on the thickness of buffer layer.The short-circuit current density increases when the interlayer thickness is small,while it gradually decreases as the buffer layer thickness increasing.When the interlayer thickness is 10nm,the short-circuit current density decreases to 0.35mA/cm2.The open-circuit voltage enhances as the buffer layer thickness increasing,from 0.43V with 1nm interlayer to 0.63V10nm interlayer.Open-circuit voltage enhancement and the short-circuit current density decrease are studied according to the integer charge transfer model and interfacial energy level theory,which provide a research foundation for the performance improvement of organic solar cells.