High-performance, stable and low-cost mesoscopic perovskite (CH₃NH₃PbI₃) solar cells based on poly(3-hexylthiophene)-modified carbon nanotube cathodes

Abstract

This work explores the use of poly(3-hexylthiophene) (P3HT) modified carbon nanotubes (CNTs@P3HT) for the cathodes of hole transporter free, mesoscopic perovskite (CH₃NH₃PbI₃) solar cells (PSCs), simultaneously achieving high-performance, high stability and low-cost PSCs. Here the thin P3HT modifier acts as an electron blocker to inhibit electron transfer into CNTs and a hydrophobic polymer binder to tightly cross-link the CNTs together to compact the carbon electrode film and greatly stabilize the solar cell. On the other hand, the presence of CNTs greatly improve the conductivity of P3HT. By optimizing the concentration of the P3HT modifier (2 mg/mL), we have improved the power conversion efficiencies (PCEs) of CNTs@P3HT based PSCs up to 13.43% with an average efficiency of 12.54%, which is much higher than the pure CNTs based PSCs (best PCE 10.59%) and the sandwich-type P3HT/CNTs based PSCs (best PCE 9.50%). In addition, the hysteresis of the CNTs@P3HT based PSCs is remarkably reduced due to the intimate interface between the perovskite and CNTs@P3HT electrodes. Degradation of the CNTs@ P3HT based PSCs is also strongly retarded as compared to cells employing the pure CNTs electrode when exposed to the ambient condition of 20%-40% humidity.

Keywords

poly(3-hexylthiophene) (P3HT) / carbon nanotube / CH₃NH₃PbI₃ / mesoscopic perovskite solar cell (PSC) / carbon cathode

References

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Acknowledgements

This work was supported by the HK Innovation and Technology Fund (ITS/004/14) and the HK-RGC General Research Funds (GRE No. HKUST 606511).

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg