Recently, organic-inorganic hybrid perovskite solar cells (PSCs) have experienced a rapid growth in terms of efficiency. However, the instability of hybrid perovskite materials towards ambient conditions restricts its commercialization. Formation...

Developing large-scale perovskite solar cells requires highquality defect-free perovskite films with improved surface coverage. One of the most convenient ways to achieve this is through the incorporation of appropriate passivation molecules in the perovskite films. Herein, the effect of a novel conjugated polyelectrolyte, PHIA, is investigated for perovskite passivation by the comprehensive analysis of perovskite films and devices. The PHIA polymer significantly diminishes the trap states in perovskite films, and the passivated device permits lesser recombination, very low accumulation of charges at the interface, and lowers the traps which facilitated superior charge transport. As a result, a high power conversion efficiency of 20.17% has been achieved for the PHIA-modified device. Additionally, this passivation approach effectively enhanced the long-term device stability by improving the hydrophobicity of the perovskite layer. Furthermore, a large-area device (2 cm 2 ) has also been fabricated to demonstrate the expediency of this approach for future commercialization.

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Precise control of perovskite morphology to achieve large-sized grains with small-width grain boundaries is challenging and a pre-requisite for realizing high photovoltaic performance. Ion migration is another problem with perovskites, which hinders the device results. Herein, the incorporation of MABr into the mixed halide perovskite MAPbCl x I3–x has been carried out to minimize ion migration by replacing the mobile I– ions in the perovskite with Br–. Moreover, the introduction of MABr results in high-quality and smooth films with large grains of average size ∼45 μm. An increasing ratio of MABr was added in the perovskite precursor solution, and devices with the architecture FTO/PEDOT:PSS/Perovskite/PCBM/Rhodamine-101/Ag were fabricated using the hot-casting technique. The device with an MABr ratio of 0.1 (0.1MABr) showed a superior power conversion efficiency of >18% compared to ∼14% of the control without any MABr. For higher ratios, the performance deteriorated due to the increase in band gap of the perovskite, which resulted in the reduction of short-circuit current density. For 0.1MABr, minimum defect states and trap density were obtained using various experimental techniques, supporting its optimum device performance. Furthermore, minimum recombination loss took place in the 0.1MABr device. Similarly, the applicability of this technique in large-area devices was studied, and an efficiency of ∼17% was obtained, which is the highest in the literature for devices with 2.5 cm2 dimensions. These innovative concepts and approaches are vital tools to achieve large-area grains for increasing the solar cell performance for commercial applications.

Hybrid perovskite solar cells (PVSCs) are extremely susceptible to moisture and heat which restricts their commercial viability. Herein, three multifunctional fluoroaromatic amine additives i.e. 4-fluoroaniline (FA), 2,4,6-trifluoroaniline (TFA) and 2,3,4,5,6-pentafluoroaniline...