Impact of Monovalent Metal Halides on the Structural and Photophysical Properties of Halide Perovskite

Abstract

In this chapter, we discuss the importance and impact of addition of metal halide additives into perovskite to enhance its semiconductor quality and realize highly efficient and stable perovskite photovoltaic devices. Monovalent metal halides have been introduced as the most promising candidates due to the their loading capacity and chemical compatibility with the perovskite materials as well as ease of incorporation and their remarkable positive impact on the crystal growth, optoelectronic properties and subsequently the performance of perovskite solar cells (PSCs). Among all the monovalent metal cations, Cs is the only one that could fit in the perovskite structure and forms photoactive perovskite and the other monovalent cations are located at the interstitials sites, grain boundaries and crystalline surfaces. We also discuss the key roles of monovalent metal halide additives that includes modulating morphology of perovskite films, modification of structural and optoelectronic properties, adjusting energy level alignment in PSCs, inhibiting non-radiative recombination in perovskites, eliminating hysteresis and enhancing operational stability of PSCs.

Cation influence on carrier dynamics in perovskite solar cells

“…[19] Jalebi et al incorporated K + in CsMAFA to mitigate the non-radiative recombination and photoinduced ion migration by passivating the defects on surface and grain boundaries. [20] The suppressed losses in perovskite films results in films with 66% photoluminescence quantum yield and in solar cells with efficiency more than 21%. Furthermore, Cao et al conducted density functional theory (DFT) calculations and demonstrate that the interstitial occupancy by inorganic cations is energetically favourable to enhance the ion migration energy barrier in the lattice.…”