Low‐Temperature Crystallization of CsPbIBr₂ Perovskite for High Performance Solar Cells

Abstract

Organic-inorganic metal halide perovskites are superstars for photovoltaics and optoelectronics due to their excellent defect tolerance, high charge mobility, tunable optical bandgap, and high absorption coefficient. [1-3] In fact, their power conversion efficiency (PCE) has been increased from 3.8% to 25.2% in just a few years. [4-6] Unfortunately, the organic components in the perovskite composition make them susceptible to stressing conditions including high temperature, chemical, and ultraviolet radiation. [7-10] Inorganic cesium halide perovskites (CsPbX 3 , X ¼ I or Br) without the organic component are attractive in the long run because of their advantages in thermal stability, and chemical resistance. [11-13] CsPbI 3 possesses an attractive bandgap of %1.73 eV to absorb most of the solar energy in visible spectrum; PSCs based on CsPbI 3 have achieved champion efficiencies as high as 19.03%. [14] Unfortunately, the desired PV active α-phase CsPbI 3 is not thermodynamically stable at room temperature. It can be easily transitioned to PV-inactive yellowish δ-phase. Such conversion leads to a considerable drop in PCE and stability. [15,16] Extensive efforts have been devoted to address these issues. Bromine has been used to partially or even completely substitute iodine in the CsPbX 3 composition. For example, a PCE of over 16% has been achieved for CsPbI 2 Br PSCs with relatively enhanced stability. [17,18] Furthermore, a PCE of 10.79% has been attained for CsPbBr 3-based PSCs with an extraordinarily high open-circuit voltage exceeding 1.6 V and decent stability upon Sm 3þ ion doping. [19] Nevertheless, its wide bandgap of %2.3 eV leads to reduced capability of solar light harvesting, which in turn limits its application. [20]

Improving Performance and Stability of Planar Perovskite Solar Cells Through Passivation Effect with Green Additives

“…In general, V OC varies logarithmically with light intensity ( I ), obeying Equation ()where n is the ideality factor, κ is the Boltzmann constant (1.38 × 10 −23 J K −1 ), e is unit electronic charge, and T is absolute temperature (290 K). [ 56 ] The fitted n values for the devices without and with FMAC are 1.82 and 1.43, respectively. It has been recognized that the deviation of this slope from κT/e is triggered by trap‐assisted recombination.…”

Lanthanide-doped inorganic halide perovskites (CsPbX3): novel properties and emerging applications

“…Zhang et al 91 used n-butylammonium iodide (BAI) in CsPbBr 2 I to improve factors like the crystallization and morphology of the structure. The BAI incorporation decreases the trap state density and nonradiative recombination and thereby facilitates preparation at the reduced annealing temperature.…”

Low‐temperature crystallization and growth of CsPbIBr 2 films through PbX 2 ‐DMSO adduct towards stable and efficient carbon‐based all‐inorganic perovskite solar cells

“…27 Zhang et al proposed low-temperature crystallization of CsPbIBr 2 film through n-butylammonium iodide (BAI) organic additive, overcoming the voltage loss. 28 It is revealed that additives, passivation layers and interfacial layers are essential to improve the perovskite film quality, device performance and stability.…”