In this paper, a new Se/CZTSSe tandem solar cell architecture is proposed as a viable approach to reach ultrahigh efficiency values at low fabrication cost. The proposed tandem design consists of a Se-based top cell with Ti intermediate ultra-thin metallic layers (MLs) and a CZTS bottom cell with graded band-gap aspect. The role of the introduced design amendments in achieving the dual-benefit of enhanced optical behavior and reduced recombination losses is investigated by means of an accurate numerical modeling. Moreover, a comprehensive study which involves the impact of design parameters such as the MLs position and the CZTSSe band-gap profile on the device performance is carried out. Moreover, Particle Swarm Optimization (PSO)-based metaheuristic technique is used to boost up the Se/CZTSSe tandem cell efficiency by identifying both the suitable position of the introduced ultrathin MLs and the appropriate CZTSSe band-gap profile. It is found that the adopted optimization approach pinpoints a new path toward achieving over 30% efficiency, not only it provides the possibility to reduce interface recombination effects by optimizing the band offset at the buffer/absorber interfaces but also enables selecting the most favorable design configuration associated with enhanced optical behavior. This makes the optimized Se/CZTSSe tandem solar cell potential alternative for providing high-efficiency and stable tandem solar cell.

In this paper, a new Se/CZTSSe tandem solar cell architecture is proposed as a viable approach to reach ultrahigh efficiency values at low fabrication cost. The proposed tandem design consists of a Se-based top cell with Ti intermediate ultra-thin metallic layers (MLs) and a CZTS bottom cell with graded band-gap aspect. The role of the introduced design amendments in achieving the dual-benefit of enhanced optical behavior and reduced recombination losses is investigated by means of an accurate numerical modeling. Moreover, a comprehensive study which involves the impact of design parameters such as the MLs position and the CZTSSe band-gap profile on the device performance is carried out. Moreover, Particle Swarm Optimization (PSO)-based metaheuristic technique is used to boost up the Se/CZTSSe tandem cell efficiency by identifying both the suitable position of the introduced ultrathin MLs and the appropriate CZTSSe band-gap profile. It is found that the adopted optimization approach pinpoints a new path toward achieving over 30% efficiency, not only it provides the possibility to reduce interface recombination effects by optimizing the band offset at the buffer/absorber interfaces but also enables selecting the most favorable design configuration associated with enhanced optical behavior. This makes the optimized Se/CZTSSe tandem solar cell potential alternative for providing high-efficiency and stable tandem solar cell.

This investigation examines mathematical modelling and experimental validation of two types of solar cookers: a box type with tilted intercept area equipped with one external reflector, and a parabolic cooker with a new configuration. Experiments were carried out with the cookers filled with two kilograms of water from 08:00 to 15:00 solar time. During the experiments, temperature gain in the box-type solar cooker was recorded at about 69.8 °C and in the parabolic-type solar cooker at 73.6 °C at the stagnation point. Direct normal irradiation in three distinct study areas was observed and found that it varied from 7.6 to 10 kWh m^-$². Cooking pot placed in parabolic cooker was varied between 130 and 132 °C. Centre and south-east regions of study areas where global irradiation varied from 8 to 8.4 kWh m^-$² were found suitable for box-type solar cooker and cooking pot temperature were found in the range of 100 °C to 105 °C. Mathematical modelling was programmed in MATLAB. The theoretical results were consistent with experiential data for both types of solar cookers. The effectiveness of the two cooker types can be deduced from the maps. It is found the use of the cookers in Northern and Southern regions of the country was not identical. Their suitability for cooking depends on the amount of solar radiations received.

This investigation examines mathematical modelling and experimental validation of two types of solar cookers: a box type with tilted intercept area equipped with one external reflector, and a parabolic cooker with a new configuration. Experiments were carried out with the cookers filled with two kilograms of water from 08:00 to 15:00 solar time. During the experiments, temperature gain in the box-type solar cooker was recorded at about 69.8 °C and in the parabolic-type solar cooker at 73.6 °C at the stagnation point. Direct normal irradiation in three distinct study areas was observed and found that it varied from 7.6 to 10 kWh m^-$². Cooking pot placed in parabolic cooker was varied between 130 and 132 °C. Centre and south-east regions of study areas where global irradiation varied from 8 to 8.4 kWh m^-$² were found suitable for box-type solar cooker and cooking pot temperature were found in the range of 100 °C to 105 °C. Mathematical modelling was programmed in MATLAB. The theoretical results were consistent with experiential data for both types of solar cookers. The effectiveness of the two cooker types can be deduced from the maps. It is found the use of the cookers in Northern and Southern regions of the country was not identical. Their suitability for cooking depends on the amount of solar radiations received.

This investigation examines mathematical modelling and experimental validation of two types of solar cookers: a box type with tilted intercept area equipped with one external reflector, and a parabolic cooker with a new configuration. Experiments were carried out with the cookers filled with two kilograms of water from 08:00 to 15:00 solar time. During the experiments, temperature gain in the box-type solar cooker was recorded at about 69.8 °C and in the parabolic-type solar cooker at 73.6 °C at the stagnation point. Direct normal irradiation in three distinct study areas was observed and found that it varied from 7.6 to 10 kWh m^-$². Cooking pot placed in parabolic cooker was varied between 130 and 132 °C. Centre and south-east regions of study areas where global irradiation varied from 8 to 8.4 kWh m^-$² were found suitable for box-type solar cooker and cooking pot temperature were found in the range of 100 °C to 105 °C. Mathematical modelling was programmed in MATLAB. The theoretical results were consistent with experiential data for both types of solar cookers. The effectiveness of the two cooker types can be deduced from the maps. It is found the use of the cookers in Northern and Southern regions of the country was not identical. Their suitability for cooking depends on the amount of solar radiations received.

This investigation examines mathematical modelling and experimental validation of two types of solar cookers: a box type with tilted intercept area equipped with one external reflector, and a parabolic cooker with a new configuration. Experiments were carried out with the cookers filled with two kilograms of water from 08:00 to 15:00 solar time. During the experiments, temperature gain in the box-type solar cooker was recorded at about 69.8 °C and in the parabolic-type solar cooker at 73.6 °C at the stagnation point. Direct normal irradiation in three distinct study areas was observed and found that it varied from 7.6 to 10 kWh m^-$². Cooking pot placed in parabolic cooker was varied between 130 and 132 °C. Centre and south-east regions of study areas where global irradiation varied from 8 to 8.4 kWh m^-$² were found suitable for box-type solar cooker and cooking pot temperature were found in the range of 100 °C to 105 °C. Mathematical modelling was programmed in MATLAB. The theoretical results were consistent with experiential data for both types of solar cookers. The effectiveness of the two cooker types can be deduced from the maps. It is found the use of the cookers in Northern and Southern regions of the country was not identical. Their suitability for cooking depends on the amount of solar radiations received.

This investigation examines mathematical modelling and experimental validation of two types of solar cookers: a box type with tilted intercept area equipped with one external reflector, and a parabolic cooker with a new configuration. Experiments were carried out with the cookers filled with two kilograms of water from 08:00 to 15:00 solar time. During the experiments, temperature gain in the box-type solar cooker was recorded at about 69.8 °C and in the parabolic-type solar cooker at 73.6 °C at the stagnation point. Direct normal irradiation in three distinct study areas was observed and found that it varied from 7.6 to 10 kWh m^-$². Cooking pot placed in parabolic cooker was varied between 130 and 132 °C. Centre and south-east regions of study areas where global irradiation varied from 8 to 8.4 kWh m^-$² were found suitable for box-type solar cooker and cooking pot temperature were found in the range of 100 °C to 105 °C. Mathematical modelling was programmed in MATLAB. The theoretical results were consistent with experiential data for both types of solar cookers. The effectiveness of the two cooker types can be deduced from the maps. It is found the use of the cookers in Northern and Southern regions of the country was not identical. Their suitability for cooking depends on the amount of solar radiations received.