Indium doped CsPbI3 films for inorganic perovskite solar cells with efficiency exceeding 17%

In recent years, all-inorganic perovskite materials have set off a research boom owing to features, such as good thermal stability, suitable bandgap, and fascinating optical properties. However, the power conversion efficiency (PCE) and the ambient stability of all-inorganic perovskite solar cells still remain a challenge. Herein, we investigate the effect of the addition of InI3 into CsPbI3 film on the corresponding device. InI3 incorporation could retard the crystallization process and control the growth rate of CsPbI3 polycrystalline films, yielding a high quality film with large grains and few voids. The increment in electrostatic potential and the reduction of carrier recombination enabled the open-circuit voltage of fabricated perovskite solar cell to be increased from 0.89 to 0.99 V. The champion device delivered a power conversion efficiency of 17.09%, which is higher than 14.36% for the reference device. And the InI3-included solar cell without any encapsulation retained 77% of its original efficiency after 860 h aging at room temperature in N2 condition.