Thermally-derived liquid phase involving multiphase Cu(In,Ga)Se2 nanoparticles for solution-processed inorganic photovoltaic devices

Abstract

In the past decade, wet chemical strategies for solution-based Cu(In,Ga)Se₂ (CI(G)Se) photovoltaic devices have gained a tremendous amount of attention in solar-cell research fields. In particular, nanoparticles allowing for liquid-phase densification have been recognized as viable candidates for advancements in photovoltaic devices. In this study, multiphase CIGSe nanoparticles are synthesized by the microwave-assisted solvothermal method, in which the chemically incorporated CuSe₂ and Se phases form liquid phases for inducing vigorous reactions at elevated temperatures. The morphological/crystalline structural properties of multiphase nanoparticles are analyzed, in conjunction with the temperature dependent evolution in multiphase nanoparticle-incorporating functional layers. Furthermore, we examine physical parameters including the cell performance, shunt conductance, and series resistance for multiphase CIGSe nanoparticle-derived solar cells, from which the cell performance-limiting factors are discussed.