Investigation of Cssn0.5ge0.5i3-On-Si Tandem Solar Device Utilizing SCAPS Simulation

With the perovskite-on-Si tandem solar technology at the onset of commercialization, it becomes imperative to tackle the toxicity concern of Pb in the perovskite structure. This study utilizes solar cell capacitance simulator (SCAPS) simulation software to investigate a tandem device with the crystalline Si (c-Si; bandgap: 1.12 eV) bottom cell in a mechanically stacked configuration with the stable and nontoxic CsSn0.55Ge0.55I3 (bandgap: 1.5 eV) as the top cell active layer. The device performance has been compared against that of a traditional tandem solar device setup utilizing MAPbI3 (bandgap: 1.55 eV) as the top cell active layer. Simulation results reveal power conversion efficiency (PCE) values of standalone CsSn0.55Ge0.55I3, MAPbI3, and c-Si cells to be 7.45%, 20.01%, and 25.95%, respectively, all in good agreement with published experimental results. The current matching condition between the top perovskite cell and the bottom c-Si cell has been probed through variation of perovskite layer thickness, yielding optimized thickness values for CsSn0.55Ge0.55I3 and,,,MAPbI3 to be 365 and 225 nm, respectively. A tandem device with CsSn0.55Ge0.55I3-on-Si showcases a PCE of 28.53% (Voc: 1.72 V; Jsc: 20.02 mA/cm²; and FF: 83.74%) compared with an MAPbI3-on-Si device yielding a PCE of 32.29% (Voc: 1.88 V; Jsc: 19.969 mA/cm²; and FF: 85.99%). The results and analyses of this study highlight the feasibility of utilizing nontoxic materials, such as CsSn0.55Ge0.55I3, to attain high tandem device PCE values

Simulation Studies to Quantify the Impacts of Point Defects: an Investigation of Cs2agbibr6 Perovskite Solar Devices Utilizing Zno and Cu2o As the Charge Transport Layers

In this investigation, we have applied SCAPS and wxAMPS to simulate defects and probe a photovoltaic device utilizing Cs2AgBiBr6 as the active photovoltaic layer and ZnO and Cu2O as the electron transport layer (ETL) and hole transport layer (HTL) respectively. At the Cs2AgBiBr6 bulk we find that with increasing defect density, each defect level has increasing impact on all device performance parameters. At a given defect density however, we find that that deeper defects have more profound impacts on Jsc and FF, and minimal effects on Voc. Specific to the Cs2AgBiBr6 structure, we have investigated VAg (shallow defect), VBi (deep defect) and Bri (quasi-deep defect). Our results provide insight into the growth conditions of Cs2AgBiBr6, with a need to have both Br-poor and Bi-rich conditions, and a preference for the latter over the former to suppress the deeper defect. Exploring the performance kinetics at the ZnO/Cs2AgBiBr6 and Cs2AgBiBr6/Cu2O interfaces due to defect type, location and density, we showcase a remarkably stable behavior in both Voc and Jsc across both interfaces. We attribute this to much higher charge mobilities in the ZnO and Cu2O compared to the Cs2AgBiBr6 layer combined with similar defect densities across the layers, leading to effective charge extraction and minimal charge recombination

Exploring Solar Cell Performance of Inorganic Cs2tibr6 Halide Double Perovskite: A Numerical Study

With a high power-conversion efficiency (PCE) of over 23%, perovskite solar cell (PSC) technology holds a viable trajectory for commercialization. Despite its attractive features, the use of lead and degradable components in the device need to be addressed. To this end, we have carried out simulation studies to explore a non-toxic and inorganic device utilizing Cs2TiBr6 as the active layer and Cu2O as the hole transport layer (HTL). We have investigated a few of the most critical areas of device physics to glean insights into possible ways of improving the performance of such a viable technology. A PCE of 14.68% (open-circuit voltage Voc of 1.10 V, short-circuit current Jsc of 25.82 mA/cm2, and fill factor FF of 51.74%) was obtained at an optimal perovskite layer thickness of 800 nm. Our investigation further reveals that with increasing perovskite thickness, as J0 (saturation current) decreases, Voc increases. By varying the radiative recombination rate, we quantitatively demonstrate an inverse relationship with PCE, and report out a PCE of 20.49% at a 100X lower than usual recombination rate. A PCE of 14.68% was obtained with an optimal work function of 5.1 eV for the metal back contact. A conduction band offset of −0.1 eV between the TiO2 electron transport layer (ETL) and the active layer and a valence band offset of −0.4 eV between the active layer and the HTL produce optimal PCE values of 14.68% and 18.97% respectively. Lastly, we demonstrate that Cs2TiBr6 is more sensitive to defect density than the device HTL and ETL by a factor of 10

Numerical Simulation Studies of a Fully Inorganic Cs2AgBiBr6 Perovskite Solar Device

With perovskite solar cell (PSC) technology on the brink of commercialization, the use of lead and degradable components remain a concern. We have carried out simulation studies to explore a non-toxic and inorganic device utilizing Cs2AgBiBr6 as the active layer and Cu2O as the hole transport layer (HTL). A maximum power-conversion efficiency (PCE) of 7.25% (open-circuit voltage Voc of 1.5V, short-circuit current Jsc of 11.45 mA/cm2, and fill factor FF of 42.1%) was obtained at an optimal perovskite layer thickness of 600 nm. Our investigation further reveals that with increasing perovskite thickness, as J0 (saturation current) decreases, Voc increases. By varying radiative recombination rate, we report out a maximum PCE of 8.11% at a 10X lower than usual rate. A conduction band offset of 0.1 eV between the TiO2 electron transport layer (ETL) and the active layer and a valence band offset of 0.35 eV between the active layer and the HTL produce optimal PCE values of 7.31% and 11.17% respectively. Lastly, we demonstrate that Cs2AgBiBr6 is more sensitive to defect density than the HTL and ETL by a factor of 100. Overall, our results are encouraging and insightful, providing guidance towards fabricating a non-toxic and inorganic perovskite solar device

Exploring solar cell performance of inorganic Cs2TiBr6 halide double perovskite: A numerical study

With a high power-conversion efficiency (PCE) of over 23%, perovskite solar cell (PSC) technology holds a viable trajectory for commercialization. Despite its attractive features, the use of lead and degradable components in the device need to be addressed. To this end, we have carried out simulation studies to explore a non-toxic and inorganic device utilizing Cs2TiBr6 as the active layer and Cu2O as the hole transport layer (HTL). We have investigated a few of the most critical areas of device physics to glean insights into possible ways of improving the performance of such a viable technology. A PCE of 14.68% (open-circuit voltage Voc of 1.10 V, short-circuit current Jsc of 25.82 mA/cm2, and fill factor FF of 51.74%) was obtained at an optimal perovskite layer thickness of 800 nm. Our investigation further reveals that with increasing perovskite thickness, as J0 (saturation current) decreases, Voc increases. By varying the radiative recombination rate, we quantitatively demonstrate an inverse relationship with PCE, and report out a PCE of 20.49% at a 100X lower than usual recombination rate. A PCE of 14.68% was obtained with an optimal work function of 5.1 eV for the metal back contact. A conduction band offset of −0.1 eV between the TiO2 electron transport layer (ETL) and the active layer and a valence band offset of −0.4 eV between the active layer and the HTL produce optimal PCE values of 14.68% and 18.97% respectively. Lastly, we demonstrate that Cs2TiBr6 is more sensitive to defect density than the device HTL and ETL by a factor of 10