Solution-processed PSS:MoOx composite thin film with triple function (passivation, antireflection, and hole-selective transport) for application in IBC solar cells

Abstract

We report a novel solution-processed organic–inorganic hybrid composite material of poly(4-styrene sulfonic acid) (PSS) and molybdenum oxide (MoO_x) nanoparticles for use at the front of interdigitated back contact (IBC) solar cells as a triple-function layer. PSS:MoO_x (PSSMo) composite films could be fabricated by a simple spin-coating and low-temperature process. For the PSSMo (1 : 10) composite film, we obtained a smoother surface morphology, outstanding reflection as low as 6%, and an excellent passivation effect of 2.4 ms. Due to the high work function (∼5.0 eV) of MoO_x nanoparticles, the PSSMo (1 : 10) composite film could provide a remarkable hole-selective transport layer. Therefore, the PSSMo composite film could have a major role in triple function (anti-reflection, passivation, and hole-selective transport) and be used as a substitute for three layers on the front of IBC solar cells. A significantly improved power conversion efficiency of >50% was obtained in the IBC solar cell with a PSSMo composite film than an IBC solar cell without such a film. Also, a device with a PSSMo thin film showed significantly greater stability within 300 min than devices with a PSS thin film under an environment condition without encapsulation because MoO_x nanoparticles provided continuous holes into the interface of PSSMo/Si. Our data could provide useful information on composites as well as the application of polymers and transition-metal oxides into silicon electronics in the future.