Role of various transport layer and electrode materials in enhancing performance of stable environment-friendly Cs2TiBr6 solar cell

Abstract

To eliminate hazardous effect of lead on environment, titanium based lead-free inorganic perovskite solar cells (SCs) have attracted intense contemporary research interest. Advantages of using titanium are its non-toxicity, high durability, low cost and ease of availability compared to other divalent elements. The sole available literature on Cs2TiBr6 published recently has experimentally used it as solar light harvesting material. Design and simulation of such SC are, therefore, very much essential to enhance its performance. We simulate Cs2TiBr6 SC for the first time and Silvaco ATLAS device simulator is used for that. Different materials are tried as transport layers to separate carriers and suppress their recombination. Here, titanium dioxide is used as electron transport material, while copper phthalocyanine, poly (3-hexylthiophene) and nickel oxide as hole transport material. For the best yield, SC is designed with appropriate thickness of each of the above layers. Photo conversion efficiency of simulated SC is obtained here as 5.5% against its experimentally reported value of 3.3%. Efficiency of 8.5% along with a fill factor of 73.6% is finally achieved from Cs2TiBr6 cell simulated with absorbing material as thick as commonly used in standard perovskite SCs. Obtained results are quite encouraging and prove potential of Cs2TiBr6 for efficient environment-benign photovoltaic applications.