Influence of Radiation on the Properties and the Stability of Hybrid Perovskites

Abstract

Organic-inorganic perovskites are well suited for optoelectronic applications. In particular, perovskite single and perovskite tandem solar cells with silicon are close to their market entry. Despite their swift rise in efficiency to more than 21%, solar cell lifetimes are way below the needed 25 years. In fact, comparison of the time when the device performance has degraded to 80% of its initial value (T lifetime) of numerous solar cells throughout the literature reveals a strongly reduced stability under illumination. Herein, the various detrimental effects are discussed. Most notably, moisture- and heat-related degradation can be mitigated easily by now. Recently, however, several photoinduced degradation mechanisms have been observed. Under illumination, mixed perovskites tend to phase segregate, while, further, oxygen catalyzes deprotonation of the organic cations. Additionally, during illumination photogenerated charge can be trapped in the NH antibonding orbitals causing dissociation of the organic cation. On the other hand, organic-inorganic perovskites exhibit a high radiation hardness that is superior to crystalline silicon. Here, the proposed degradation mechanisms reported in the literature are thoroughly reviewed and the microscopic mechanisms and their implications for solar cells are discussed.

Slow Hot‐Carrier Cooling in Halide Perovskites: Prospects for Hot‐Carrier Solar Cells

“…[135][136][137] Importantly, the hot-phonon bottleneck, Auger-heating, and/or band-filling effects in halide perovskites will enable the HC temperatures and lifetimes to be greatly increased under high excitation fluence. [138] Thermal management with active/passive cooling may be necessary even for low concentrator halide perovskite photovoltaics. Another advantage of concentrator-HCSC is that the increased voltage-to-current can decrease the resistive losses under the high current densities of concentrator cells.…”

Effective Singlet Oxygen Generation in Silica‐Coated CsPbBr3 Quantum Dots through Energy Transfer for Photocatalysis

“…Perovskites have many excellent functional properties owing to their special structural characteristics, such as high absorption coefficient, wide absorption range covering the entire visible region, adjusted band gap, long diffusion length of electrons and holes, high bipolar charge mobility, and extended carrier lifetime . Despite their excellent optoelectronic properties, bare perovskites shows poor stability in polar solvents and under light irradiation, which hinders their development and application in photocatalysis . Recently, Park et al .…”

Controlled n‐Doping in Air‐Stable CsPbI2Br Perovskite Solar Cells with a Record Efficiency of 16.79%

“…The champion power conversion efficiency (PCE) of organic–inorganic hybrid perovskite solar cells (PSCs) has skyrocketed to a certified value of 25.2% 1. However, the labile organic cationic methylamine (MA) and formamidine (FA) components in the hybrid perovskites easily escape or decompose at high temperature, which leads to poor long‐term stability of hybrid PSCs under heat and high‐humidity conditions 2,3. To overcome the instability issue of the organic cations, a series of heat‐resistant inorganic CsPbX 3 (X: I, Br, or mixed halides) perovskites have been developed for PSCs, which are also tolerant to oxygen exposure and ultraviolet irradiation 4–6.…”

“…[1] However, the labile organic cationic methylamine (MA) and formamidine (FA) components in the hybrid perovskites easily escape or decompose at high temperature, which leads to poor long-term stability of hybrid PSCs under heat and high-humidity conditions. [2,3] To overcome the instability issue of the organic cations, a series of heat-resistant inorganic CsPbX 3 (X: I, Br, or mixed halides) perovskites have been developed for PSCs, which are also tolerant to oxygen exposure and ultraviolet irradiation. [4][5][6] Among all the inorganic perovskites, the mixed halide CsPbI 2 Br has attracted intensive attention due to its excellent thermal/light soaking stability and suitable direct bandgap, potentially in the front cell for perovskite-silicon hybrid tandem applications.…”

“…[16][17][18] High E loss linked to high defect density (large nonradiative energy loss) and mismatched bandgaps lead to the decreased V oc . Therefore, high-quality perovskite films and desirable energy-level alignments in CsP-bI 2 Br PSCs are keys to reducing energy losses and improving V oc . In order to improve the V oc of a CsPbI 2 Br device, Chen et al applied a gradient thermal annealing and antisolvent method to retard the crystallization process of CsPbI 2 Br film, resulting in a uniform and high-quality perovskite film and an improved V oc of 1.23 V. [19] Tian et al introduced an amino-functionalized polymer, PN4N, as a novel cathode interlayer, demonstrating that the PN4N interlayer is conducive to the quality of the perovskite film, and the conduction-band alignment between the electron transport layer and perovskite resulted in an improved V oc of 1.30 V. [20] Our group has developed a precursor engineering method using Pb(Ac) 2 as an additive to enhance the built-in potential in CsPbI 2 Br PSCs, leading to a significant enhancement of V oc from 1.22 to 1.30 V. [21] However, the E loss relative to the bandgap of CsPbI 2 Br (E g : 1.92 eV) is still as high as 0.62 eV.…”