High Performing Semitransparent Graphene/BiFe0.95Si0.05O3/ITO Ferroelectric Photovoltaic Device

Enriched and versatile room temperature multiferroic, BiFeO₃ has been widely appreciated for future generation optoelectronic devices including light detectors, terahertz emitters, tunable solar cells, micro-sensors, and thin-film transistors with additional degree of magnetic and electric control. Moreover, literature also highlights its adjustable electrical, optical, and ferroelectric properties by doping with selected elements. We hereby report substantial photovoltaic response of semitransparent graphene/semiconductor Si doped BiFeO₃ hetero-structure fabricated on In₂O₃ doped SnO₂ coated glass substrates using bottom up spin coating technique considering the commercial aspect. The short circuit current density Jsc and open circuit voltage V_OC were measured as 75 mA/cm² and 0.45 V, respectively, with approximately 3 orders of increase in current density under standard AM1.5 (100 mW/cm²) illumination at room temperature. For the first time crystal structure, optical band gap, leakage behavior, ferroelectric and magnetic characteristics of 5 mol% Si doped BiFeO₃ polycrystalline thin films is investigated and reported. Quick and reproducible transient response of J_SC and V_OC with (t_on,t_off  <100 ms) for more than 50 consecutive cycles establishes high scale of endurance and retentivity. Further, high stability (95%) of photo-response of chemically derived photovoltaic cell over a period of 16 weeks was achieved in ambient condition. This work establishes BiFe_0.95Si_0.05O₃ as a high performing multiferroic material with complementary graphene and ITO as electrodes for self-powered oxide electronics.