Comparative study of natural dye-sensitized solar cells using inedible extracts from kumkum, kamala and malabar spinach fruits

•The natural dye extracted from the inedible source, Bixa orellana seed, pericarp of Mallotus phillipensis fruits and ripe fruits of Basella alba.•The extracted dyes were utilized as the sensitizer in the dye-sensitized solar cell.•The highest efficiency of 0.67% was achieved in the case of Bixa orellana (kumkum) seed extract compared to others.•Photophysics of all the dyes were studied using DFT and TDDFT.•These natural dyes extracted from inexpensive inedible sources can provide the best alternative to synthetic dye.