Enhancing the stability and efficiency of MAPbI3 perovskite solar cells by theophylline-BF4 - alkaloid derivatives, a theoretical-experimental approach.

Perovskite solar cells (PSCs) are an evolving photovoltaic field with the potential to disrupt the established silicon solar cell market. However, the presence of many transport barriers and defect trap states at the interfaces and grain boundaries has negative effects on PSCs; it decreases their efficiency and stability. The purpose of this work was to investigate the effects on efficiency and stability achieved by quaternary theophylline additives in MAPbI3 PSCs with the structure FTO/TiO2/perovskite/spiro-OMeTAD/Ag. The X-ray photoelectron spectroscopy (XPS) and theoretical calculation strategies were applied to study the additive's interaction in the layer. The tetrafluoroborinated additive results in an increase in device current density (J SC) (23.99 mA cm-1), fill factor (FF) (65.7%), and open-circuit voltage (V OC) (0.95 V), leading to significant improvement of the power conversion efficiency (PCE) to 15.04% compared to control devices (13.6%). Notably, films exposed to controlled humidity of 30% using the tetrafluoroborinated additive maintained their stability for more than 600 hours (h), while the control films were stable for less than 240 hours (h).

Study on photovoltaic stability and performance by incorporating tetrabutyl phosphonium iodide into the active layer of a perovskite type photovoltaic cell.

A simple synthesis of an ionic liquid is carried out using a trialkylphosphine and an alkyl halide. The results showed that the quality of perovskite crystals is enhanced by the incorporation of B4PI, when the percentage is 1.5% the PCE of champion PSCs MA98.5(B4PI)1.5PbI3 increases significantly from 15.5%, with a V OC of 0.957 mV, J SC of 23.6 mA cm-2, and an FF of 68.4%. Stability tests show that excess B4PI by 20% has a protective effect against humidity, MA80(B4PI)20PbI3 was more stable towards humidity, losing only 20% efficiency for 200 h.

Crystal structure of 1,3-di-cyclo-hexyl-1-[3-(pyren-1-yl)prop-anoyl]urea.

In the title compound, C33H38N2O2, each of the cyclo-hexyl rings adopts a chair conformation. The two planes involving carbonyl groups, C-(C=O)-N and N-(C=O)-N, are oriented at a dihedral angle of 62.28 (10)°. In the crystal, two neighboring mol-ecules are linked by a pair of N-H⋯O inter-actions, generating an inversion dimer. The dimers are inter-connected by C-H⋯O hydrogen bonds into a supra-molecular chain along the a-axis direction.