Halide perovskite is considered a promising photovoltaic material owing to high charge-carrier mobility, extended carrier lifetime, substantial absorption coefficient and defect tolerance. The power conversion efficiency (PCE) of small-area perovskite solar cells (PSCs) has escalated from 3.8% to exceeding 26 %. Moreover, their potential lies in ability to be fabricated on glass or plastic substrates offering advantages such as high power-to-weight ratio, portability, and suitability for integration on curved surfaces.

These low-cost and efficient PSCs hold great promise for commercial applications. Various printing methods consider to be advanced preparation processes that align well with large-scale manufacturing to achieve superior quality upscaled perovskite films.

However, despite the promising performance, the commercial development of perovskite solar cells encounter the challenge of using toxic solvents that pose environmental and health hazards. Moreover, operational layers on plastic substrates require annealing at temperatures lower than 140 ⁰C. This demands meticulous fabrication of charge transporting layers and absorber films to maintain high output performance.

In this work, we made complex investigation for the modification of nip PSCs on glass and plastic (PET) substrates manufactured by blade coating and spin coating low-temperature (up to 120 °C) processing with completely avoiding hazardous solvents. This is a significant advancement in making the production process more environmentally friendly and safer for workers.

The possibility of obtaining high-quality active layers is increased by technological optimization perovskite deposition from DMSO solution, which is polar, but has significant viscosity and high boiling point. These properties complicate the liquid deposition processes and the evaporation rate from the active layer during crystal film formation. To increase wettability, an additive of acetonitrile was used, which has a low donor number, but allows increasing the rate of solution evaporation from the wet film due to its lower boiling point. Thus, high quality perovskite films were obtained by optimally selected green solution concentrations and improved deposition process.

Over 21% of PCE was achieved, which is higher than the efficiencies presented in the related field using green perovskite solvents and utilizing spin coating technique [1–3]. The impact of the modification on the output characteristics of solar cells was estimated under the light of a solar simulator.