A large area and highly stable perovskite solar module (10 cm × 10 cm, active area ∼70 cm2) is demonstrated using low cost processing methods and materials.

Hybrid perovskites are recently developed photoactive semiconductors that hold great promise for next-generation solar cells, with devices incorporating them reaching certified efficiencies as high as 22.1%. [1] This high performance is coupled with a relative low cost, as perovskites comprise earth-abundant elements that are amenable to deposition from the solution-state by scalable, inexpensive printing processes. [2] Recent work has focused on improving their long-term stability with significant progress being reported in encapsulation techniques and scalability with the production of modulescale devices (100 cm 2 ) exhibiting efficiencies of over 11%. [3][4][5][6] These developments have resulted in efforts to commercialize perovskite solar cells; however, there is still concern over the potential to achieve the 25-year service lifetimes necessary to make perovskites a disruptive technology.Photoactive perovskite semiconductors are highly tunable, with numerous inorganic and organic cations readily incorporated to modify optoelectronic properties. However, despite the importance of device reliability and long service lifetimes, the effects of various cations on the mechanical properties of perovskites are largely overlooked. In this study, the cohesion energy of perovskites containing various cation combinations of methylammonium, formamidinium, cesium, butylammonium, and 5-aminovaleric acid is reported. A trade-off is observed between the mechanical integrity and the efficiency of perovskite devices. High efficiency devices exhibit decreased cohesion, which is attributed to reduced grain sizes with the inclusion of additional cations and PbI 2 additives. Microindentation hardness testing is performed to estimate the fracture toughness of single-crystal perovskite, and the results indicated perovskites are inherently fragile, even in the absence of grain boundaries and defects. The devices found to have the highest fracture energies are perovskites infiltrated into a porous TiO 2 /ZrO 2 /C triple layer, which provide extrinsic reinforcement and shielding for enhanced mechanical and chemical stability. Perovskite Solar CellsThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

A fully printable, hole‐conductor‐free perovskite solar cell with a simple and low‐cost fabrication route and high stability is well placed for commercialization. We aim to simplify the fabrication process of these solar cells by replacing the mesoporous TiO2 (meso‐TiO2) layer with a thick ZrO2 layer. This new architecture required only three steps: screen‐printing first the compact TiO2 (c‐TiO2), second the mesoporous ZrO2 layer (for perovskite infiltration), and third the carbon electrode. To improve the solar cell performance of the architecture, the c‐TiO2 and ZrO2 printing process are optimized. After systematic optimization of these processes, we found that the double‐printing of the c‐TiO2 layer and an increase of the ZrO2 later thickness from 1.4 to 2.1 μm in the device structure gives an optimized efficiency of 9.69 %, which is comparable to that of standard carbon devices with meso‐TiO2. This method provides an approach to reduce the fabrication time and thermal budget for fully printable solar cells.

Excess lead iodide (PbI2) has been reported to improve the power conversion efficiency (PCE) in the standard perovskite solar cell (PSC) with 2,2,7,7‐Tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)‐9,9‐ spirobifluorene (spiro‐OMeTAD) as a hole‐transporting material. In this study, we studied the effect of having excess PbI2 in fully printable carbon‐based perovskite solar cells (PSC). Excess amounts of PbI2, ranging from 0 % to 15 %, were added to the equimolar perovskite solution for infiltration in the carbon‐based PSC architecture. There was an improvement in the average value of open‐circuit voltage (0.87 to 0.91 V) with increased PbI2, but there was no clear trend in fill factor and current density. All devices showed good stability under ambient conditions without encapsulation. The device containing 15 % excess PbI2 showed degradation under continuous illumination, whereas there was no degradation with an equimolar ratio of perovskite precursors.