Steps toward efficient inorganic–organic hybrid perovskite solar cells

Crystalline silicon dominates the solar panel industry today but remains relatively expensive to manufacture. If devices could be fabricated from inexpensive materials by a simple solution process without the need for high-temperature annealing, their cost could be considerably reduced. Recently, inorganic–organic (I/O) hybrid systems based on inorganic nanoparticles (including quantum dots) and perovskite materials as light harvesters with organic hole-conducting materials have shown great potential for efficient solar cells due to the combination of superior optical properties and solution-based processes. In this review, we describe the relevant morphological factors and the performance of perovskite solar cells with tuned heterojunctions. In particular, we describe the mediator retarding the rapid crystallization of perovskite layers for a bilayer configuration. Appropriate processes and chemical engineering induced the formation of well-crystallized perovskite materials with extremely uniform and dense perovskite layers and remarkably improved the performance of the cells with a National Renewable Energy Laboratory (NREL)-certified record efficiency of 20.1%.