Effect of TiO<sub>2</sub> layer thickness of TiO<sub>2</sub>/NiO transparent photovoltaics
Naveen Kumar, Malkeshkumar Patel, Thanh Tai Nguyen, Sangho Kim, Joondong Kim
Abstract
Abstract The rapid growth in the transparent electronics industry has increased the need for transparent photovoltaic cells (TPCs) and transparent self‐powered devices. To make TPCs and transparent self‐powered devices more efficient, a detailed understanding of device structure is needed. In this study, TiO 2 /NiO heterojunction‐based TPCs were fabricated with different TiO 2 layer thicknesses, and the effect of TiO 2 layer thickness on the photovoltage and photocurrent was evaluated. All the fabricated TiO 2 /NiO heterojunction‐based devices had a high optical transparency (>50%) in the visible–near‐infrared (vis–NIR) region. The fabricated devices were illuminated with different power sources of different wavelengths. If the TiO 2 layer was too thick or too thin, the TPC performance deteriorated. By growing the optimal 100‐nm‐thick TiO 2 layer, a simultaneous tunability between high optical transparency and high photovoltaic performance was achieved. A TiO 2 /NiO heterojunction‐based device with an optimal 100‐nm‐thick TiO 2 layer had the highest optical transparency (>60%) in the vis–NIR region, with the highest photovoltage of 685.00 ± 68.06 mV and the highest photocurrent of 4.42 ± 1.35 mA under the illumination of a light source with a power density of 70 mW/cm 2 at a wavelength of 365 nm. The fabricated TPCs had a high sensitivity to ultraviolet (UV) signals and demonstrated self‐powered behavior. This study clarified the role of TiO 2 layer thickness optimization in improving the performance of TiO 2 /NiO heterojunction‐based TPCs.