Perovskite is an emerging material for high performance solar cell application with low-cost solution-processable fabrication. As an ink, perovskite composition can be easily modified to create semi-transparent solar cells for window replacement. To enable scalable large-scale production, the spray process is one of the major candidates. In this work, we developed sequential spray deposition (SSD) to create double layer absorbers from different dimensional perovskites. SSD, for the first time, achieves layer-by-layer deposition of different perovskite materials for stacked architecture. To demonstrate the benefits, we spray-coated lower dimension, more stable perovskite onto high performance yet sensitive 3D semi-transparent perovskite. SSD performed under a humid environment (40 - 50% RH) brings about better film stability and retains good performance of 3D perovskite. Sequential spray deposition opens new routes for various stacking designs and large-scale production under economical ambient conditions.

Low dimensional perovskites via DMF : DMSO = 8 : 2 with potential for semi-transparent solar cell led to superior surface morphology with large crystallite size and low defects.

Perovskite materials are emerging as suitable materials for low-cost, high efficiency optoelectronics. In this study, we reported the surface modification of 2D (PEA)2PbBr4 for violet emission using PEG doping followed by a newly developed step called swift cation doping (SCD) where phenylethylammonium cations (PEA+) in isopropanol (IPA) are abruptly applied during crystallization. 2D Perovskite doped with PEG using SCD resulted in smaller grain, smoother surface, higher film density, higher photoluminescence quantum efficiency, and longer average PL lifetime. These features are highly beneficial for photoluminescence application and can be easily applied to enhance other perovskite LED thin films.

Perovskite materials have gained a lot of interest in LED application because of their excellent properties, such as direct band gap nature, high photoluminescence quantum efficiency (PLQE), high charge carrier mobility, pure color emission with small full width at half maximum, and low non-radiative recombination rate. In this work, we for the first time, developed a new protocol called vacuum assisted crystallization (VAC) for perovskite luminescence applications and optimized different parameters i.e. vacuum pressure, holding time, and annealing time. VAC is an after-deposition process applicable to control nanoscale domain structure and improve phase distribution for various deposition techniques, causing small grain size and dense formation beneficial for high luminescence. Large PLQE enhancement, smooth bright emission, high stability, and good surface morphology were obtained with VAC treatment.