Improved moisture resistance and interfacial recombination of perovskite solar cells by doping oleylamine in spiro-OMeTAD based hole-transport layer

Abstract

Hydrophobic and long-chain molecule oleylamine is used to modify the spiro-OMeTAD matrix, which is then adopted for the hole-transport layer in perovskite solar cells. It is observed that after moderate doping, the power conversion efficiency of the devices increases from 17.82 (±1.47)% to 20.68 (±0.77)%, with the optimized efficiency of 21.57% (AM 1.5G, 100 mW/cm2). The improved efficiency is ascribed to the favored charge extraction and retarded charge recombination, as reflected by transient photovoltage/photocurrent curves and impedance spectroscopy measurement. In addition, the grazing incidence photoluminescence spectrum reveals that oleylamine doping causes a blue shift of the luminescence peak of the surface layer of the halide perovskite film, while the Mott−Schottky study observes 100 mV increment in the built-in potential, both of which indicate possible defect passivation behavior on the perovskite. Moreover, an accelerated damp test observes that moisture resistance of the device is also upgraded, which is due to the improved hydrophobicity of the spiro-OMeTAD matrix.

Efficient and Stable Perovskite Solar Cells with a High Open‐Circuit Voltage Over 1.2 V Achieved by a Dual‐Side Passivation Layer

“…These results indicate that the incorporation of poly-BCP suppressed the nonradiative recombination induced by both trap-assisted recombinations at the bulk PVK absorber and minority carrier recombination at the ETL/PVK interface. [56,[73][74][75][76][77] Finally, we examined the photostability (maximum power point tracking stability) of non-encapsulated PSCs under continuous photoillumination (AM 1.5G, 100 mW cm −2 ) in a nitrogen atmosphere. As shown in Figure 5f, the PSCs with poly-BCP have higher operational stability; after 750 h of exposure, the PSC with poly-BCP exhibited 7% degradation relative to the initial efficiency, whereas a 17% degradation from the initial efficiency was observed in the control device.…”