Researchers are making strides toward developing all-inorganic antimony sulfide solar cells by utilizing nickel oxide as the hole transport material, vastly improving efficiency and stability. Solar energy conversion is increasingly seen as one of the best solutions to address global energy demands, prompting extensive research aimed at enhancing photovoltaic technologies.
The recent study shifts focus toward semi-transparent solar cells using antimony sulfide (Sb2S3) combined with nickel oxide (NiOx) as the hole-transporting material (HTM). Unlike traditional organic HTMs, which face issues such as high cost and instability, NiOx presents several advantages, including chemical stability, suitable energy level alignment, and high optical transmittance. This makes it particularly appealing for flexible and semi-transparent applications, such as solar windows.
The study was led by researchers including A. Pareek, A. Katerski, and M. Kriisa, affiliated with various institutions and supported by the Estonian Research Council. By modifying the precursor solution concentration ranging from 0.2 M to 1.2 M through a simple chemical precipitation method, the researchers were able to observe significant effects on the physical and optical properties of the synthesized NiOx nanoparticles.
The optimal NiOx layer, formed using 0.5 M precursor concentration, achieved impressive power conversion efficiency (PCE) of 2.68%. This marked a 60% increase over Sb2S3 solar cells without HTM. The highest recorded efficiency indicates promising prospect for commercialization and practical applications of these innovative solar cells.
Power conversion efficiency is one of the major parameters defining the effectiveness of solar materials. The study noted improvements across key cell parameters as NiOx was integrated as the HTM, leading to enhanced open-circuit voltage (Voc) values and reduced recombination of charge carriers, significantly increasing overall efficiency.
The researchers elucidated the properties of NiOx nanoparticles using advanced characterization methods such as X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. A detailed examination revealed the nanoparticle crystallite size influenced by precursor concentration, where larger diameters increased with higher concentration, impacting the band gap from 3.70 eV to lower values.
With advancements paving the way for solar materials to enter new market sectors, this study provides relevant insights. Their findings indicate how the lyophilized nanoparticle films can offer semi-transparent solutions, exhibiting properties suitable for effective and aesthetically appealing solar cells.
The authors concluded by advocating the potential of NiOx to serve as high-quality HTM for Sb-based solar cells, which could revolutionize energy conversion technologies for environmentally sustainable applications. The success of this study builds upon previous work showcasing the efficiency of alternative material systems and sets the stage for future innovations.
By providing stable solutions to some of the pressing challenges in solar energy conversion, researchers are contributing to the global dialogue surrounding renewable energy and sustainable practices. Continued exploration of material innovations like NiOx is key to advancing solar technologies and increasing their integration within everyday environments.