OICC Press International Nano Letters 2228-5326 11 3 (September 2021) 2021 04 12 Magnesium-doped green solar cells using natural chromophores 10.1007/s40089-021-00334-0 EN Immaculata O. Onuigbo Department of Petroleum Chemistry, American University of Nigeria, Yola, NG Garba N. Abdulrahman Department of Petroleum Chemistry, American University of Nigeria, Yola, NG Chukwuma Onwujiuba Department of Petroleum Chemistry, American University of Nigeria, Yola, NG Oscar Iwu Department of Petroleum Chemistry, American University of Nigeria, Yola, NG Muhammed Falalu Yahaya Department of Petroleum Chemistry, American University of Nigeria, Yola, NG Wan Jin Jahng Department of Petroleum Chemistry, American University of Nigeria, Yola, NG Journal Article 2021 04 12 Abstract The current study tested the hypothesis of whether specific metal doping may show synergy with plant chromophore-based solar cells using a titanium dioxide (TiO 2 ) electrode. A natural dye-sensitized, magnesium-doped TiO 2 solar cell was assembled using the methanol extract from various western African plants including Lawsonia inermis (henna). Mg 2+ –TiO 2 nanoparticles were applied on fluorine-doped tin oxide (FTO) glass to serve as the photoanode of the solar cells with I-/I3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I^{ - } /I_{3}^{ - }$$\end{document} electrolyte. A surface-modified TiO 2 photoanode was prepared through the immersion method using a selective dopant including magnesium and potash. An inductively coupled plasma-optical emission spectrophotometer (ICP-OES) was utilized to characterize the potash dopant for comparative analysis. Instrumental analysis including ultraviolet–visible spectroscopy (UV–Vis), infrared spectroscopy (IR), and gas chromatography and mass spectrometry (GC–MS) analysis were carried out to characterize the natural henna dye extracts. The photovoltaic performance including open-circuit voltage ( V oc ), short circuit current density ( J sc ), current ( I ), and power output ( P ) was analyzed quantitatively. ICP-OES analysis demonstrated that potash contains a composite of 26 elemental metals with K and Na accounting for 72.2% (5192.2 mg/kg) and 9.5% (682.6 mg/kg), respectively. GC–MS analysis confirmed the presence of lawsone and tocopherol in henna extracts. Among the tested samples, the Mg-doped TiO 2 group generated the highest improvement in J sc , from 0.66 to 1.28 (mA/cm 2 ), representing a 93% increase. Our experiments demonstrated that the presence of magnesium as a doping agent improves the photogenerated electron transport and the light-harvesting performance of the henna dye to increase the overall efficiency of light-to-electricity conversion of the photovoltaic cells.