Improving the Structural, Optical and Photovoltaic Properties of Sb- and Bi- Co-Doped MAPbBr3 Perovskite Solar Cell

We prepared 1% Bi- and (0, 0.5%, 1% and 1.5%) Sb- co-doped MAPbBr3 films by a sol-gel spin coating technique. For the first time, the detailed structural properties including grain size, dislocation line density, d-spacing, lattice parameters, and volume of co-doped MAPbBr(3) films have been investigated. XRD confirmed the cubic structure of MAPbBr(3) with high crystallinity and co-doping of Bi and Sb. The 1% Bi and 1% Sb co-doping have a surprising effect in MAPbBr(3) structures, such as large grain size (59.5 nm), d-space value (6.23 angstrom), small dislocation line dislocation (2.79 x 1018 m(-2)), and small lattice parameters (a = b = c = 6.3 angstrom) and volume of unit cell. The detailed optical properties, including energy band gap (Eg), refractive index (n), extinction coefficient (k) and dielectric constant (sigma), which are very important for optoelectronics applications, were investigated by UV-Vis spectroscopy. The film of 1% Bi and 1% Sb co-doped MAPbBr(3) showed good optical response including small Eg, high n, low value of k, high real and low imaginary parts of dielectric constant, making it good for solar cell applications. Solar cells were fabricated from these films. The cell fabricated with pure MAPbBr(3) has Jsc of 8.72 mA cm(-2), FF of 0.66, Voc of 1.29 V, and eta of 7.5%. All the parameters increased by co-doping of Bi and Sb in MAPbBr(3) film. The cell fabricated with 1% Bi and 1% Sb co-doped MAPbBr3 film had high current density (12.12 mA-cm(-2)), open circuit voltage (Voc), fill factor (0.73), and high efficiency (11.6%). This efficiency was 65% larger than a pure MAPbBr3-based solar cell.