Charge Carrier Dynamics of Active Material Solar Cell P3HT:ZnO Nanoparticles Studied by Muon Spin Relaxation (μSR)

Abstract

Poly (3-hexylthiohene) (P3HT) has attracted much attention due to their chemical and thermal stability as well as their potential to be used as an active material in solar cells. Recently, hybrid solar cell has been developed due to the combining advantages of organic material (P3HT) and inorganic material such as nanoparticle zinc oxide (ZnO). ZnO is an inorganic material with high electron mobility and easy to prepare as electron acceptor to dissociate excitons formed in conjugated polymer as the active material of solar cells. ZnO also can be prepared as a nanoparticle that can resolve a problem of small exciton diffusion length of P3HT. However, the clearly explanation about the effect of ZnO to the charge carrier dynamics in P3HT is not fully understanding yet. We have studied charge carrier dynamics in active material of solar cell P3HT:ZnO along and perpendicular to the chain by means of longitudinal field (LF) muon-spin-relaxation (μSR) method to elucidate the intra and inter-chain charge carrier in polymer hybrid P3HT:ZnO. We found the charge carrier transport changes from intra-chain to inter-chain diffusion. One dimensional intra-chain diffusion is observed in the samples at low temperatures, while three dimensional inter-chain is observed at high temperatures.