Ambient fabrication of perovskite solar cells through delay-deposition technique

Abstract

The establishment of perovskite solar cells (PSCs) in terms of their power-conversion efficiency (PCE) over silicon-based solar cells is undeniable. The state-of-art of easy device fabrications of PSCs has enabled them to rapidly gain a place in third-generation photovoltaic technology. Numerous obstacles remain to be addressed in device efficiency and stability. Low performance owing to easily degraded surface and deterioration of perovskite film quality resulting from humidity are issues that often arise. This work explored a new approach to producing high-quality perovskite films prepared under high relative humidity (RH = 40%–50%). In particular, the ubiquitous 4-tert-butylpyridine (tBp) was introduced into lead iodide (PbI2) precursor as an additive, and the films were fabricated using a two-step deposition method followed by a delay-deposition technique of methylammonium iodide (MAI). High crystallinity and controlled nucleation of MAI were needed, and this approach revealed the significance of time control to ensure high-quality films with large grain size, high crystallography, wide coverage on substrate, and precise and evenly coupled MAI molecules to PbI2 films. Compared with the two-step method without time delay, a noticeable improvement in PCE from 3.2 to 8.3% was achieved for the sample prepared with 15 s time delay. This finding was primarily due to the significant enhancement in the open-circuit voltage, short-circuit current, and fill factor of the device. This strategy can effectively improve the morphology and crystallinity of perovskite films, as well as reduce the recombination of photogenerated carriers and increase of current density of devices, thereby achieving improved photovoltaic performance.

Stabilizing high-humidity perovskite solar cells with MoS2 hybrid HTL

“…The small peak declines for M1–M4 samples proportionally, which proves that the layer can repel moisture from being captivated into the other layers although the fabrication process is done under high humidity conditions (RH = 40–50%). The other characteristic peaks correspond well to MAPbI 3 (at 2θ = 14.5° and 28.7°) for all samples with crystal size obtained ~ 31.9 nm 42 , 43 . In addition, some miscellaneous peaks were detected, which explained the presence of residual CH 3 NH 3 I will be decomposed and the product of I 2 .…”

Influence of graphene dispersion on the photovoltaic performance of tandem solar cells with four-terminal perovskite–polycrystalline silicon configuration

“…The degradation rate of perovskite top cells can affect the overall tandem module degradation and consequently reduce the module's lifetime energy and cost-effectiveness. Several methods, such as encapsulation [12,13], interfacial engineering [14][15][16][17] and chemical passivation [18,19], are used to improve the long-term stability of sensitive perovskite top cells.…”