Solid-State Solar Cells Based on TiO2 Nanowires and CH3NH3PbI3 Perovskite

Perovskite inorganic-organic solar cells are fabricated as a sandwich structure of mesostructured TiO2 as electron transport layer (ETL), CH3NH3PbI3 as active material layer (AML), and Spiro-OMeTAD as hole transport layer (HTL). The crystallinity, structural morphology, and thickness of TiO2 layer play a crucial role to improve the overall device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide excellent light trapping with open voids for active filling of visible light absorber compared to bulk TiO2. Solid-state photovoltaic devices based on randomly distributed TNWs and CH3NH3PbI3 are fabricated with high open circuit voltage V-oc of 0.91 V, with conversion efficiency (CE) of 7.4%. Mott-Schottky analysis leads to very high built-in potential (V-bi) ranging from 0.89 to 0.96 V which indicate that there is no depletion layer voltage modulation in the perovskite solar cells fabricated with TNWs of different lengths. Moreover, finite-difference time-domain (FDTD) analysis revealed larger fraction of photo-generated charges due to light trapping and distribution due to field convergence via guided modes, and improved light trapping capability at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2.

Automated summary

The perovskite inorganic-organic solar cells utilize a sandwich structure consisting of mesostructured TiO2, CH3NH3PbI3, and Spiro-OMeTAD, with the crystallinity, structural morphology, and thickness of the TiO2 layer playing a crucial role in improving device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide better light trapping and active filling compared to bulk TiO2, leading to high open circuit voltage and conversion efficiency in solid-state photovoltaic devices. Finite-difference time-domain (FDTD) analysis shows improved light trapping capabilities at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2.