[1] N Asima, K Sopiana, S Ahmadib et al. A review on the role of materials science in solar cells. Renew Sustain Energy Rev, 16, 5834(2012).

[2] A E Rakhshani. Preparation, characteristics and photovoltaic properties of cuprous oxide – a review. Solid-State Electron, 29, 7(1986).

[3] G P Pollack, D Trivichi. Photoelectric properties of cuprous oxide. J Appl Phys, 46, 163(1975).

[4] J Herion, E A Niekisch, G Scharl. Investigation of metal oxide/cuprous oxide heterojunction solar cells. Sol Energy Mater, 4, 101(1980).

[5] L Papadimitriou, N A Economou, D Trivich. Heterojunction solar cells on cuprous oxide. Sol Cells, 3, 73(1981).

[6] L C Olsen, F W Addis, W Miller. Experimental and theoretical studies of Cu₂O solar cells. Sol Cells, 7, 247(1982).

[7] W M Sears, E Fortin, J B Webb. Indium tin oxide/Cu₂O photovoltaic cells. Thin Solid Films, 103, 303(1983).

[8] B P Rai. Cu₂O solar cells: A review. Sol Cells, 25, 265(1988).

[9] R N Briskman. A study of electrodeposited cuprous oxide photovoltaic cells. Sol Energy Mater Sol Cells, 27, 361(1992).

[10] T Minami, Y Nishi, T Miyata et al. High-efficiency oxide solar cells with ZnO/Cu₂O heterojunction fabricated on thermally oxidized Cu₂O sheets. Appl Phys Express, 4, 062301(2011).

[11] Y S Lee, J Heo, S C Siah et al. Ultrathin amorphous zinc-tin-oxide buffer layer for enhancing heterojunction interface quality in metal-oxide solar cells. Energy Environ Sci, 6, 2112(2013).

[12] T Minami, Y Nishi, T Miyata. High-efficiency Cu₂O-based heterojunction solar cells fabricated using a Ga₂O₃ thin film as n-type layer. Appl Phys Express, 6, 044101(2013).

[13] S W Lee, Y S Lee, J Heo et al. Improved Cu₂O-based solar cells using atomic layer deposition to control the Cu oxidation state at the p–n junction. Adv Energy Mater, 4, 1301916(2014).

[14] Y S Lee, D Chua, R E Brandt et al. Atomic layer deposited gallium oxide buffer layer enables 1.2 V open-circuit voltage in cuprous oxide solar cells. Adv Mater, 26, 4704(2014).

[15] T Minami, Y Nishi, T Miyata. Heterojunction solar cell with 6% efficiency based on an n-type aluminum–gallium–oxide thin film and p-type sodium-doped Cu₂O sheet. Appl Phys Express, 8, 022301(2015).

[16] Y Ievskaya, R L Z Hoye, A Sadhanala et al. Fabrication of ZnO/Cu₂O heterojunctions in atmospheric conditions: Improved interface quality and solar cell performanceSol. Energy Mater Sol Cells, 135, 43(2015).

[17] R L Z Hoye, R E Brandt, Y Ievskaya et al. Perspective: Maintaining surface-phase purity is key to efficient open air fabricated cuprous oxide solar cells. APL Mater, 3, 020901(2015).

[18] T Minami, T Miyata, Y Nishi. Efficiency improvement of Cu₂O-based heterojunction solar cells fabricated using thermally oxidized copper sheets. Thin Solid Films, 559, 105(2014).

[19] T Minami, T Miyata, Y Nishi. Cu₂O-based heterojunction solar cells with an Al-doped ZnO/oxide semiconductor/thermally oxidized Cu₂O sheet structure. Sol Energy, 105, 206(2014).

[20] T Minami, Y Nishi, T Miyata. Cu₂O-based solar cells using oxide semiconductors. J Semicond, 37, 014002(2016).

[21]

[22] T Minami, Y Nishi, T Miyata. Impact of incorporating sodium into polycrystalline p-type Cu₂O for heterojunction solar cell applications. Appl Phys Lett, 105, 212104(2014).