In recent years, perovskite solar cells (PSCs) have gained major attention as potentially useful photovoltaic technology due to their ever-increasing power-conversion efficiency (PCE). The efficiency of PSCs depends strongly on the type of materials selected as the electron transport layer (ETL). TiO₂ is the most widely used electron transport material for the n-i-p structure of PSCs. Nevertheless, ZnO is a promising candidate owing to its high transparency, suitable energy band structure, and high electron mobility. In this investigation, hybrid mesoporous TiO₂/ZnO ETL was fabricated for a perovskite solar cell composed of FTO-coated glass/compact TiO₂/mesoporous ETL/FAPbI₃/2D perovskite/Spiro-OMeTAD/Au. The influence of ZnO nanostructures with different percentage weight contents on the photovoltaic performance was investigated. It was found that the addition of ZnO had no significant effect on the surface topography, structure, and optical properties of the hybrid mesoporous electron-transport layer but strongly affected the electrical properties of PSCs. The best efficiency rate of 18.24% has been obtained for PSCs with 2 wt.% ZnO.

Purpose: The photovoltaic modules with front glass as a protective layer are the most popular type in the industry, but for some applications it can be considered as too heavy. One of the approaches is to laminate the cells using PMMA [Poly(methyl methacrylate)] as the front layer. This polymer has good mechanical strength and optical properties but exhibits low adhesion to lamination foil. To increase adhesion between these two materials, PMMA surface treatment may be required. Design/methodology/approach: To examine the PMMA treatment influence on the sample, adhesion samples’ surfaces were modified by grinding and laser cutting. Also two types of PMMA available in the market were tested, namely, smooth and satin types. The quality of lamination was determined using two methods, namely, tear test with recorded maximal tear force achieved for the samples, and environment chamber tests, in which the system resistance against the cyclic temperature variation was evaluated. Findings: Additional treatment of the PMMA surface lead to increased adhesion of the lamination foil used. Ethylene-vinyl acetate foil in the PMMA system is sensitive to temperature variation, which can lead to system delamination, whereas polyvinyl butyral foil exhibits better environmental performance and even its adhesion to PMMA is lower. Originality/value: This paper presents atypical surface modification methods that contributed to higher adhesion of lamination systems in glass-free solar modules. Glass front sheet and polymeric backsheet were replaced with PMMA. As the adhesion mechanism in the PMMA-lamination foil system differs from that in the traditional glass system, different PMMA surface treatments need to be evaluated.