One of the most critical challenges in fabricating perovskite solar cells is the lack of an effective hole transport layer with stability and reasonable price. Almost all of the hole transport layer used in high-efficiency solar cells is based on Spiroʹs organic materials, which are up to ten times more expensive than gold and platinum. On the other hand, inorganic p-type semiconductors such as nickel oxide are cost-effective compared to the organic hole transport layer. Besides, features such as a broad energy band gap, high conductivity, stability, and resistance to moisture and solution-based manufacturing processes make this nanostructured inorganic hole transport layer a viable alternative to organic materials. This study aimed to eva‎luate the characteristics and mechanism of nickel oxide as a hole transport layer in the structure of nanostructured inverted perovskite solar cells made at low temperature and compare it with nickel oxide performance doped with cobalt as a hole transport layer. Low intrinsic electrical conductivity and the high amount of defects when it is synthesized at low temperature, resulting in increased charge recombination and reduced hole extraction, have blocked further improvement to NiOx-based PSCs. To overcome this drawback and keep the temperature low, two main methods have been investigated: interlayersʹ addition for controlling the interface. Besides metal ion doping, Different metals are used to dope the NiOx, like Au+, Cu2+, Co3+, and Li+. Among other metals, Co is a promising dopant. For this purpose, at first, nickel oxide nanoparticles doped with varying amounts of cobalt were synthesized by the co-precipitation method and used as a solar cell photoanode. Numerous cells with an inverted structure including transparent conductive oxide ITO - hole transport layer (nickel oxide) - perovskite - an electron-conducting layer of butyl methyl ester (PCBM) - the protective interlayer of Fullerene C60 and Batocoprine (BCP) - silver bonding by spin coating methods And thermal evaporation, were made. Their structural, optical, and electrical properties were eva‎luated under different conditions. In solar cells with a pure nickel oxide as a hole transport layer, the fill factor was about 70%, the current density was 19.5 mA / cm2, the open-circuit voltage was 0.97 V, and the efficiency was 13.2%. With the cobalt dopant, the values of high photovoltaic parameters increased favorably compared to pure nickel oxide. For the dopant 0.75 mol% cobalt, fill factor of about 76%, current density of 21.5 mA / cm2, open-circuit voltage 1 volt, and 16.42% efficiency were obtained. In the structure of nanostructured inverted perovskite solar cell with pure nickel oxide hole transport layer and using the protective interlayer of fullerene, the fill factor is about 71%, the current density is 21.5 mA / cm2, open-circuit voltage is 1 V, and efficiency is 15.2 % Was obtained.

احمد كرمانپور، فتح الله كريم زاده

مجيد مقدم، عباس بهرامي، مهدي رنجبر