Enhancing photovoltaic performance of perovskite solar cells with silica nanosphere antireflection coatings

Abstract

Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing higher power conversion efficiency (PCE) of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells (PSCs). Here, we focus on another significant aspect that is to minimize the light loss by using an antireflection coating (ARC) component to gain a high PCE for PSC devices. In our scheme, silica nanosphere based ARCs are employed to CH3NH3PbI3 PSCs for enhancing the device efficiency. SiO2 nanosphere based ARCs were grown by spin-coating of an aged silica sol. The microstructure and the thickness of the SiO2 nanosphere based ARC were controlled by changing the spin-coating speed from 400 to 4000 rpm. The effect of SiO2 nanosphere based ARCs on the photovoltaic performance of perovskite solar cells is systematically investigated. The optimized SiO2 nanosphere ARC coating on cleaned glass substrate exhibited a maximum transmittance of 96.1% at λ = 550 nm wavelength, and averagely increased the transmittance by about 3.8% in a broadband of 400–800 nm. The optimized antireflection coating strongly suppressed broadband and wide-angle reflectance in typical PSC solar cells, significantly enhancing the omnidirectional photovoltaic (PV) performance of PSCs. As a result, the power conversion efficiency was improved from 14.81% for reference device without SiO2 nanospheres to 15.82% for the PSC device with the optimized ARC. Also, the PV performance of the PSC device with the optimized SiO2 nanosphere ARC revealed less angular dependence for incident light.