The roles of traps in the energy loss for aged organic solar cells: A transient photovoltage study

► We report roles of traps in energy loss for aged OSCs by transient photovoltage. ► Peaks after turn-on and turn-off were observed for microseconds in aged device. ► Peaks are affected by light intensity, background illumination and pulse width. ► Roles of traps were verified by adding Alq3 buffer.