An inherent instability study using ab initio computational methods and experimental validation of Pb(SCN)2 based perovskites for solar cell applications

Jayita Dutta,Beena Rai,Jinesh Kochupurackal B,Soumya Dutta,Umesh R Kadhane,Mithun Chennamkulam Ajith

doi:10.1038/s41598-020-72210-4

Abstract

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.

Highlights

Perovskite materials with ABX3 chemistries are promising candidates for photovoltaic applications, owing to their suitable optoelectronic properties
Band structure, bandgap Density of States (DOS), Projected Density of States (PDOS) were computed for five different CH3NH3PbI(3−x)(SCN)x stoichiometry at x = 0, 0.25, 0.49, 1.0, 1.45 which corresponds to 0, 8.33, 16.66, 33.32, 49.98% (SCN)− respectively[4]
A correlation was established between DFT computed perovskite stoichiometry at a varying percentage of (SCN)− and synthesized perovskite chemistries at varying concentrations of Pb(SCN)[2]

Summary

Introduction

Perovskite materials with ABX3 chemistries are promising candidates for photovoltaic applications, owing to their suitable optoelectronic properties. Perovskite materials consisting of metal halides have gained interest as a solar material because of their superior optoelectronic properties such as direct bandgap (≈ 1.5 eV), high light absorption coefficient, ambipolar charge transport abilities, long carrier lifetime, and high carrier mobility. They are suitable for active solar materials for different types of photovoltaic architecture[4]. Synthesis of metal halide perovskites involves cost-effective, easy and simple synthesis methods like one-step or two-step solution processing, or by vapor deposition techniques or by vapor assisted solution processing to ensure uniform film morphology[4] These advantages make perovskites, superior candidates for photovoltaic applications. The compact ( PbI2)–2-AET–(MAI) molecule was reported to make the perovskite film intrinsically hydrophobic and the perovskite is reported to retain its crystal structure for > 10 min after immersion in w ater[10,13]

Methods

Results

Conclusion