ABSTRACT
The tandem solar cell is a kind of multi-junction solar cell, made of different materials with different bandgaps and absorption spectra, resulting in absorption of a broad range of wavelengths and an increase in the efficiency of converting more photons into electrical energy. Another problem with PSCs is the toxicity of lead (Pb), a limiting factor that, in addition to operational instability, prevents commercial use of perovskite solar cells. To replace lead with non-toxic material, the Pb-free absorbers should have low toxicity and proper stability. This chapter deals with quantum dots, tandem, and Pb-free PSCs in detail. All-inorganic perovskite quantum dots or nanocrystals exhibit improved phase stability due to the less surface strain caused by reducing the size of perovskite grains. Properties of perovskites quantum dots (PQDs) can be controlled by the halide composition, size, and shape of PQDs as well as multiple generation effect.
