Double moth-eye structures to reduce parasitic absorbed and reflected in homojunction perovskite solar cells

Perovskite materials for solar cells have excellent optical performance to achieve over 90% light absorption without trapping structure. However, the perovskite solar cell structure determines the occurrence of light loss, because light needs to pass through the window layer before being effectivity absorbed. In this work, we use a combination of double moth-eye structures in ITO and PDMS films to reduce parasitic absorption and reflection. It is shown that the moth-eye structure can smoothly change the vertical refractive index to reduce the light reflection generated by multiple functional layers. In addition, the moth-eye structure in ITO film can regulate the internal light field distribution, directly affecting parasitic absorption, and reducing the parasitic absorption by 62.98%. After optimization of this double moth-eye structure, the maximum current density obtained is 25.93 mA cm-2, which is 9.78% higher than that of the perovskite solar cell without moth-eye structure.