N-Type Molybdenum Diselenide-Based Liquid Junction Solar Cells: A Non-Aqueous Electrolyte System Employing the Chlorine/Chloride Couple

摘要

Single crystal, n-type MoSe2 is shown to serve as a stable photoanode in an electrochemical cell employing a nonaqueous (CH3CN) solution of Cl2/Cl(-) as the redox active material. The photoanode reaction is 2Cl(-) Cl2 and the cathode reaction is Cl2 2Cl(-). The MoSe2 is qualitatively beter than MoS2 (0.5% efficiency) which has a larger band gap (1.7 eV), but both materials are rugged in the nonaqueous solution while both photocorrode in aqueous Cl(-) solutions. In H2O, the I3(-)/I(-) couple is excellent but in CH3CN it yields lower efficiency than the Cl2/Cl(-) couple. The stable Cl2(-)/Cl(-) system provides evidence that a transparent, reversible, non-02 sensitive redox couple can be useful in n-type semiconductor-based liquid junction cells employing a direct band gap material having optimum solar response.