An inherent instability study using ab initio computational methods and experimental validation of Pb(SCN)₂ based...

Perovskite materials with ABX₃ chemistries are promising candidates for photovoltaic applications, owing to their suitable optoelectronic properties. However, they are highly hydrophilic and unstable in nature, limiting the commercialization of perovskite photovoltaics. Mixed halide ion-doped perovskites are reported to be more stable compared to simple ABX₃ chemistries. This paper describes ab initio modeling, synthesis, and characterization of thiocyanate doped lead iodide CH₃NH₃PbI_(3-x)(SCN)_x perovskites. Several perovskite chemistries with an increasing concentration of (SCN)^- at x = 0, 0.25, 0.49, 1.0, 1.45 were evaluated. Subsequently, 'n-i-p' and 'p-i-n' perovskite solar device architectures, corresponding to x = 0, 0.25, 0.49, 1.0 thiocyanate doped lead halide perovskite chemistry were fabricated. The study shows that among all the devices fabricated for different compositions of perovskites, p-i-n perovskite solar cell fabricated using CH₃NH₃PbI_(3-x)(SCN)_x perovskite at x = 1.0 exhibited the highest stability and device efficiency was retained until 450 h. Finally, a solar panel was fabricated and its stability was monitored.