Effect of spray pressure on optical, electrical and solar cell efficiency of novel Cu2O thin films

Cu2O thin films were deposited by nebulizer spray pyrolysis technique using different pressure rates. Structural, morphological, optical, photoluminescence, electrical and solar cell studies were done. The structural studies confirmed that the deposited Cu2O thin films are in polycrystalline nature having cubic crystal structure matching with the standard JCPDS Card. No (77-0199). Laser Raman analysis confirmed that all peaks are correspond to Cu2O phase. Optical analysis showed band gap values 2.26, 2.12 and 1.99 eV for pressures 1, 2 and 3 bars, respectively. Photoluminescence analysis confirmed that the emission peak obtained at 617 nm corresponds to cuprous oxide phase. Films deposited at high pressure i.e. 3 bars showed low resistivity 1.73 x 10(2) Omega.cm. Solar cells were fabricated using the deposited Cu2O film with ZnO as heterojunction that showed fill factor values 0.29, 0.35 and 0.39 for pressures 1, 2 and 3 bars, respectively. The power conversion efficiency (eta) was increased from 0.039 to 0.57% (about 15 times) by increasing the pressure from 1 to 3 bars.