4.5 Candidates for the HER . . . . . . . . . . . . . . . . . . . . . . 35
5 Materials for Light Absorption 42
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.2 Mechanism of photoelectrochemical water splitting . . . . . . . 43
5.3 Different methods for the bandgap calculation . . . . . . . . . . 44
5.4 Candidates for photoelectrochemical water splitting . . . . . . 46
5.5 Bandgap engineering of functional perovskites . . . . . . . . . . 49
5.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
6 Trends in Stability and Bandgaps of Binary Compounds in
Different Crystal Structures 58
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.2 Results and Discussions . . . . . . . . . . . . . . . . . . . . . . 59
6.3 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7 Final Remarks 71
Bibliography 72
Papers 82
Paper I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Paper II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Paper III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Paper IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138