Topology Engineering of Heteroatom-Embedded Xanthones as Hole Conductors for Efficient and Stable Air-Processed Perovskite Solar Cells

Lead-free tin perovskite solar cells

Hole and electron transport materials: A review on recent progress in organic charge transport materials for efficient, stable, and scalable perovskite solar cells

Photovoltaics literature survey (no. 149)

Decoupling the effects of defects on efficiency and stability through phosphonates in stable halide perovskite solar cells

Interface engineering with NiO nanocrystals for highly efficient and stable planar perovskite solar cells

Mixed‐halide perovskites have emerged as outstanding light absorbers that enable the fabrication of efficient solar cells; however, their instability hinders the commercialization of such systems. Grain‐boundary (GB) defects and lattice tensile strain are critical intrinsic‐instability factors in polycrystalline perovskite films. In this study, the light‐induced cross‐linking of acrylamide (Am) monomers with non‐crystalline perovskite films is used to fabricate highly efficient and stable perovskite solar cells (PSCs). The Am monomers induce the preferred crystal orientation in the polycrystalline perovskite films, enlarge the perovskite grain size, and cross‐link the perovskite grains. Additionally, the liquid properties of Am effectively releases lattice strain during perovskite‐film crystallization. The cross‐linked interfacial layer functions as an airtight wall that protects the perovskite film from water corrosion. Devices fabricated using the proposed strategy show an excellent power conversion efficiency (PCE) of 24.45% with an open‐circuit voltage (VOC) of 1.199 V, which, to date, is the highest VOC reported for hybrid PSCs with electron transport layers (ETLs) comprised of TiO2. Large‐area PSC modules fabricated using the proposed strategy show a power conversion efficiency of 20.31% (with a high fill factor of 77.1%) over an active area of 33 cm2, with excellent storage stability.

Interfacial passivation is the focal point for the preparation of efficient and stable perovskite solar cells. A holistic modification strategy employing multifunctional interfacial material of [1]benzothieno[3,2-b][1]benzothiophene-2-amine (BTBT-NH2) between tin oxide and perovskite is presented in this paper. It can be chemically linked to tin oxide by Lewis base coordination to reduce the oxygen vacancy in tin oxide. Furthermore, BTBT-NH2 containing lone pair electrons can passivate unliganded lead ions in perovskite and anchor lead iodide completely at the bottom of perovskite through N-H bond, forming more nucleation sites and improving the film-forming quality and crystallinity of PbI2 and perovskite. Further analysis reveals that the modification of BTBT-NH2 can reduce trap density, thus suppressing charge recombination and improving power conversion efficiency (PCE). Surprisingly, after being stored at 22 °C and 30% relative humidity in ambient conditions for nearly 1000 h, the unpackaged device maintains 90% of its initial PCE. The results show that BTBT-NH2 interfacial modification is an effective strategy for obtaining stable and efficient perovskite solar cells.

It is well known that tailoring the interfacial structure is very important for perovskite solar cells, especially for its performance and stability. Here, we report a universal and versatile method of modulating the energetic alignment between the perovskite and hole-transporting layer by introducing a multifunctional dipole layer based on metallophthalocyanine derivatives copperphthalocyanine (CuPc) or highly fluorinated copper hexadecafluorophthalocyanine (F16CuPc). Both molecules were introduced through an "antisolution" process to treat the surface of organic-inorganic CH3NH3PbI3 perovskite. The dipole layer can well align the interfacial energy levels, passivate the CH3NH3PbI3 surface, and fill the grain boundaries, resulting in greatly suppressed charge recombination. As a result, our planar CH3NH3PbI3 perovskite devices exhibit the best power conversion efficiency of 20.2%, with significantly enhanced open-circuit voltages ( Voc) of 1.112 V (CuPc) and 1.145 V (F16CuPc), which is a record high Voc value for CH3NH3PbI3 thin-film solar cells. More importantly, the use of highly fluorinated F16CuPc produces a significantly more hydrophobic surface, leading to drastically improved long-term stability under ambient conditions. We believe that our study offers a general approach to making multifunctional dipole layers, which are necessary for achieving both stable and efficient perovskite solar cells.

Passivating the defective surface of perovskite films is becoming a particularly effective approach to further boost the efficiency and stability of their solar cells. Organic ammonium halide salts are extensively utilized as passivation agents in the form of their corresponding 2D perovskites to construct the 2D/3D perovskite bilayer architecture for superior device performance; however, this bilayer device partly suffers from the postannealing-induced destructiveness to the 3D perovskite bulk and charge transport barrier induced by the quantum confinement existing in the 2D perovskite. Hence, developing direct passivation of the perovskite layer by organic ammonium halides for high-performance devices can well address the above-mentioned issues, which has rarely been explored. Herein, an effective passivation strategy is proposed to directly modify the perovskite surface with an organic halide salt 4-fluorophenethylammonium iodide (F-PEAI) without further postannealing. The F-PEAI passivation largely inhibits the formation of the iodine vacancies and thus dramatically reduces the film defects, resulting in a much slower charge trapping process. Consequently, the F-PEAI-modified device achieves a much higher champion efficiency (21%) than that (19.5%) of the control device, which dominantly results from more efficient suppression of interfacial nonradiative recombination and the subsequent decreased recombination losses. Additionally, the F-PEAI-treated device maintains 90% of its initial efficiency after 720 h of humidity aging owing to the enhanced hydrophobicity and decreased trap states, highlighting good ambient stability. These results provide an effective passivation strategy toward efficient and stable perovskite solar cells.

Reducing carrier transport barrier in anode interface enables efficient and stable inverted mesoscopic methylammonium-free perovskite solar cells

Revealing phase evolution mechanism for stabilizing formamidinium-based lead halide perovskites by a key intermediate phase

Multifunctional buried interface engineering via phenyl-phosphonic acid for efficient and stable SnO2-based planar perovskite solar cells

Interlayer modification between the perovskite and charge transport layers is critical to minimize trap-assisted recombination losses and promote highly efficient and stable perovskite solar cells. However, the cost and complexity of most modification materials limit the rapid development of perovskite photovoltaic technology. In this study, we propose Tris(1-chloro-2-propyl) phosphate (TCPP) as a cost-effective and efficient solution for interfacial modification. Theoretical calculations and experimental results demonstrate that the P=O group in TCPP effectively passivate both deep energy level defects and shallow defects of perovskite. This interaction enhances crystallinity, leading to high-quality films and improved solar cell efficiencies, achieving up to 20.73%. Our work presents the potential of organic molecules constructed with P=O group for enhancing both the efficiency and stability of perovskite solar cells, paving the way for their commercial viability.

Hydrogen bond enables highly efficient and stable two-dimensional perovskite solar cells based on 4-pyridine-ethylamine

Highly efficient and stable carbon-based perovskite solar cells with the polymer hole transport layer