Investigation of the GO effect on CdS quantum dot sensitized PV-cells based on the GO–TiO₂ nanocomposite photoanode: modeling using the Lambert function

Titanium dioxide (TiO₂) and graphene oxide-TiO₂ (GO-TiO₂) photoanode nanocomposite solar cells, incorporating CdS quantum dots, were analyzed. The current and power density <i>versus</i> voltage characteristics of the fabricated photovoltaic (PV) cells were measured under different power densities. A fourfold increase in short-circuit current density, from 0.481 mA cm^-2 to 2 mA cm^-2, was observed by adding 0.12 g of graphene. This increase in performance is attributed to the enhanced electrical and optical properties provided by graphene, which generates more charge carriers and increases the density of electron-hole pairs by absorbing white light. Quantum dots were also employed to improve the solar cell performance. The capacitance-frequency characteristics of the graphene-TiO₂ composite photoanode, based on CdS quantum dots, were studied with graphene. The negative capacitance behavior of PV cells with graphene was investigated, revealing that graphene significantly influences these values. As a result, adding graphene enhanced the inductive behavior of the quantum dot-sensitized solar cells (QDSSCs). The electrical characteristics of the solar cells were studied, and the experimental data for current and power density <i>versus</i> voltage were simulated using the Lambert function to explain the effect of graphene on the inductive behavior of TiO₂/CdS-based cells.