• Energy Research

The choice of hole-transport materials (HTMs) has a strong impact on electric field-induced degradation of perovskite solar cells (PSCs). Rational design of HTMs is necessary to make PSCs sufficiently stable for the targeted practical applications.

New conjugated (BDT-TTBTBTT)n copolymers are featured as promising hole-transport materials for n–i–p perovskite solar cells delivering efficiencies of up to ∼19%.

Photoinduced aging of a widely used perovskite light absorber such as CsPbI2Br can be suppressed significantly by usingd,l-asparagine as a stabilizing agent.

Perovskite solar cells represent a highly promising third-generation photovoltaic technology. However, their practical implementation is hindered by low device operational stability, mostly related to facile degradation of the absorber materials under exposure to light and elevated temperatures. Improving the intrinsic stability of complex lead halides is a big scientific challenge, which might be addressed using various “molecular modifiers”. These modifiers are usually represented by some additives undergoing strong interactions with the perovskite absorber material, resulting in enhanced solar cell efficiency and/or operational stability. Herein, we present a derivative of 1,4,6,10-tetraazaadamantane, NAdCl, as a promising molecular modifier for lead halide perovskites. NAdCl spectacularly improved both the thermal and photochemical stability of methylammonium lead iodide (MAPbI3) films and, most importantly, prevented the formation of metallic lead Pb0 as a photolysis product. NAdCl improves the electronic quality of perovskite films by healing the traps for charge carriers. Furthermore, it strongly interacts with the perovskite framework and most likely stabilizes undercoordinated Pb2+ ions, which are responsible for Pb0 formation under light exposure. The obtained results feature 1,4,6,10-tetraazaadamantane derivatives as highly promising molecular modifiers that might help to improve the operational lifetime of perovskite solar cells and facilitate the practical implementation of this photovoltaic technology.

A study of fullerene derivatives as electron-transport materials for perovskite solar cells revealed that their crystal structures affect charge transport and device efficiency, while the operational stability is governed by the film uniformity.

The designed copolymer PATTBTT delivered a power conversion efficiency of 17.6% in PSCs, which was higher than those obtained for reference devices fabricated using conventional polytriarylamine-based hole-transport materials.

Efficient and economic oxidative polymerization enables the synthesis of polytriarylamines (PTAAs), which show comparable performances to high-cost commercial PTAAs in perovskite solar cells delivering efficiencies of 18–20%.

ABSTRACTThe partial Pb2+ substitution with Cu+ ions has been thoroughly applied as an approach to produce new absorber materials with enhanced light and radiation hardness required for potential aerospace applications of perovskite solar cells. X‐ray photoelectron spectroscopy revealed that Cu+ ions are partially integrated into the crystal lattice of MAPbI3 on the surface of perovskite grains and induce p‐doping effect, which is crucial for a range of applications. Importantly, the presence of Cu+ enhances photostability of perovskite films and blocks the formation of metallic lead as a photolysis product. Furthermore, we have carried out one of the first studies on the radiation hardness of complex lead halides exposed to two different stressors: γ‐rays and 8.5 MeV electron beams. The obtained results demonstrate that Cu+ doping alters completely the radiation‐induced degradation pathways of the double cation perovskite. Indeed, while Cs0.12FA0.88PbI3 degrades mostly with segregation of δ‐phase of FAPbI3 forming a Cs‐rich perovskite phase, the Cs0.12FA0.88Pb0.99Cu0.01I2.99 films tend to expel δ‐CsPbI3 and produce FA‐rich perovskite phase, which shows impressive tolerance to both γ‐rays and high energy electrons. The beneficial effect of copper ion incorporation on the stability of lead halide perovskite solar cells under light soaking and γ‐ray irradiation conditions has been shown. The discovered possibility of controlling the electronic properties and major materials degradation pathways through minor modification of their chemical composition (e.g., replacing 1% of Pb2+ with Cu+) opens up tremendous opportunities for engineering new perovskite absorber compositions with significantly improved properties for both terrestrial and aerospace applications. image