Efficiency enhancement of Si solar cell based on spectral down-shifting property of CsGeBr3 optimized by time and temperature of synthesis

Organic-Inorganic lead halide perovskites with properties of tunable photoluminescence, high efficiency in visible light absorption and high thermal stability have attracted a lot of attention in recent years as a light-absorbing layer in optoelectronic devices including solar cells. One of the main limitations in the development and application of these structures is the lead toxicity. In this research, synthesis of CsGeBr3 as inorganic lead-free perovskite is studied in various solution temperatures and times. X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, diffuse reflectance spectroscopy, Fourier transform infrared and photoluminescence are applied to study crystalline structures, morphology, elemental percentages, and optical properties of the CsGeBr3. The results illustrate that the adjusting of solution temperature and reaction time is an effective approach to synthesize lead-free perovskite of CsGeBr3 with high quality. It is found that 360 min reaction time and the solution temperature of 120 degrees C are suitable synthesis parameters to obtain optimized CsGeBr3 perovskite. Moreover, the current-voltage characteristic curve is applied to diagnose the Si solar cell performance before and after drop-casting of the optimized CsGeBr3 as light-absorbing layer. The findings reveal that the CsGeBr3 perovskite enhances efficiency and fill factor of the Si solar cell due to its down-shifting property. According to quantum efficiency (QE), blue and red photons have different behavior on performance of the Si solar cell in the presence of the CsGeBr3 perovskite. Regarding results, QE of solar cell related to blue photons enhances in the presence of CsGeBr3 perovskite, while the CsGeBr3 perovskite does not play any role to increase QE of the red photons.

Automated summary

The study demonstrates that adjusting the solution temperature and reaction time is an effective method for synthesizing high-quality lead-free perovskite CsGeBr3. The CsGeBr3 perovskite enhances efficiency and fill factor of Si solar cells due to its down-shifting property.