Low-temperature solution-processed molybdenum oxide thin film as ITO modified layer for polymer solar cells

Abstract In this experiment, the molybdenum oxide (MoO X ) layer were fabricated by spin-coated ammonium heptamolybdate ((NH 4 ) 6 Mo 7 O 24 -4H 2 O) solution and thermal annealing treatment. The MoO X layer is shown the deeper energy level, which is more match the highest occupied molecular orbital (HOMO) energy level of the donor. The effect of the thermal annealing of the MoO X layer on hole mobility and photovoltaic performance was investigated. It was found that the 16 nm thick MoO X layer has the best hole mobility and photovoltaic performance as a HEL device. From the space charge limited current (SCLC) and time of flight (TOF) curve, the MoO X layer has shown the better hole extract and transport ability compared with polyethylenedioxy-thiophene:polystyrenesulfonate (PEDOT:PSS, Clevios Al4083) layer. The photocurrent density versus effective voltage ( J ph  −  V eff ) curve, short-circuit current ( J SC ) and open-circuit voltage ( V OC ) value dependent on incident light intensity is confirmed that the weaken charge carrier recombination of MoO X -based PSCs at the open circuit condition and short circuit condition. After prolonged light illumination (during ten days), the MoO X -based PSCs is shown the better photo-stability compared with PEDOT:PSS-based PSCs and the similar decrease ratio compared with inverted PSCs.